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  • More Swine Flu Information

    The 2009 flu pandemic is a global outbreak of a new strain of a influenza A virus subtype H1N1, referred to as the “novel H1N1”first identified in April 2009, and commonly called “Swine flu.” It is thought to be a reassortment of four known strains of influenza A virus one endemic in (normally infecting) humans, one endemic in birds, and two endemic in pigs (swine). Transmission of the new strain is human-to-human, with cooked pork products safe to eat as the virus cannot be transmitted by eating foods.

    The outbreak began in Mexico, with evidence that Mexico was already in the midst of an epidemic for months before the outbreak was recognized. Soon after, its government closed down most of Mexico City’s public and private offices and facilities to help contain the spread. In early June, as the virus spread globally, the World Health Organization (WHO) declared the outbreak to be a pandemic, but also noted that most illnesses were of “moderate severity.” The virus has since spread to the Southern Hemisphere which entered its winter flu season, and to many less developed countries with limited healthcare systems. Because the virus was spreading with “unprecedented speed”, and many clinics were overwhelmed testing and treating patients, WHO stopped requiring countries to report all cases, but is still monitoring unusually large outbreaks

    The virus typically spreads from coughs and sneezes or by touching contaminated surfaces and then touching the nose or mouth. Symptoms, which can last up to a week, are similar to those of seasonal flu, and may include fever, sneezes, sore throat, coughs, headache, and muscle or joint pains. The U.S. Centers for Disease Control and Prevention (CDC) notes that most cases worldwide are usually mild, and most hospitalizations and deaths have been of persons that also had underlying conditions such as asthma, diabetes, obesity, heart disease, or a weakened immune system. The CDC’s Anne Schuchat states, “this is a virus that’s capable of causing a spectrum of illness that includes severe complications and death. . . It’s very important we take this virus seriously”. As the virus spreads easily between people, through the air or surface contact, those who get the flu are recommended to stay home from school or work and avoid crowds to avoid spreading the infection further.

    In an attempt to slow the spread of the illness, a number of countries, especially in Asia, have quarantined airline passengers with flu symptoms, while some are also pre-screening passengers. WHO does not expect to have a full vaccine before the end of 2009, and vaccines available sooner may be limited and given first to healthcare workers, pregnant women, and other higher risk groups. Two or three injections will be required for maximum immunity from both the swine flu and seasonal flu. There is also concern if the new virus mutates further, it could become more virulent and less susceptible to any new vaccine.

    Initial outbreaks

    It is not known where the virus originated.[118][119] Analysis has suggested that the H1N1 strain responsible for the current outbreak first evolved around September 2008 and circulated in the human population for several months before the first cases were identified as being due to a new strain.[118][120][121]


    The virus was first reported in two U.S.children in March, but health officials have said that it apparently infected people as early as last January in Mexico.[122] The outbreak was first detected in Mexico City on March 18, 2009,[123] and health officials later confirmed an outbreak in Veracruz state in February.[124][125] Immediately after the outbreak was officially announced, Mexico requested material support from the U.S., sending samples to the U.S. and Canada for testing. Soon after, the CDC helped Mexico perform quicker diagnoses and confirmations.[126] Within days of the outbreak, Mexico City was “effectively shut down,” and some countries hastily canceled flights to Mexico while others halted trade. Calls to close the border to contain the spread were rejected by Homeland Security Secretary Janet Napolitano, who called it “pointless,” as the virus had already crossed into the U.S.[126]

    Scientists tried to understand why there were so many deaths in Mexico while infections in the United States and Canada were relatively mild. Some experts now assume that Mexico already had hundreds of thousands, and possibly millions, of cases before the outbreak was officially recognized, and were therefore in the midst of a “silent epidemic.”[127] As a result, Mexico was reporting only the most serious cases, and led a CDC expert to speculate at the time, “We may just be looking at the tip of the iceberg, which would give you a skewed initial estimate of the case fatality rate.”[123]

    Some experts conjecture that virus “most likely” emerged from pigs in Asia, and was carried to North America by infected persons; however no proof exists for this line of reasoning.[128]

    United States

    The new strain was first diagnosed in two children, neither of whom had been in contact with pigs, by the CDC, first on April 14, 2009 in San Diego County, California and a few days later in nearby Imperial County, California[129][130] (it was not identified as a new strain in Mexico until 24 April[131]).


    Deaths Confirmed casesSee also: H1N1 live mapWHO updates

    The Public Health Agency of Canada announced that their National Microbiology Laboratory (NML) had mapped the genetic code of the swine flu virus, the first time that was done.[132]

    U.S officials noted that six years of worrying about H5N1 avian flu did much to prepare for the current swine flu outbreak, noting that after H5N1 emerged widely in Asia in 2003, killing about 60 percent of the humans infected by it, many countries took steps to prevent any similar crisis.[133] Dr. Schuchat with the CDC, agreed, saying, “This really was a wake-up call for the world. We actually have been preparing for a pandemic for many years now.” [134] She added that the CDC would now use the current lull to take stock of the United States’s response to the new H1N1 flu and attempt to patch any gaps in the public health safety net before flu season starts this autumn. She cited a new report which found that recent cuts in public health departments have meant many did not have adequate resources to carry out flu plans.[135]

    Travel advisories

    The new strain has spread widely beyond North America with confirmed cases in eighty-nine countries. Initially, most cases outside North America were following recent travel to Mexico or the U.S. However by May 15 in-country transmission had been reported from Canada, Japan, Panama, the UK, Spain, Germany, Australia, Italy, and Belgium,[136] and as of June 17 most countries within the European Union had documented in-country transmission[137] as had many countries worldwide.[138]

    Many countries had earlier advised citizens to avoid travelling to infected areas and were monitoring visitors returning from flu-affected areas for flu symptoms. WHO guidance from 7 May recommends no travel restrictions based on this strain of influenza stating that “Scientific research based on mathematical modelling shows that restricting travel would be of limited or no benefit in stopping the spread of disease”.[139] The CDC downgraded a previous “Travel Health Warning” for Mexico to a “Travel Health Precaution” on May 15 referring to the reduction in infections in Mexico and the reduced overall risk of the virus.[140]

    On June 22, the U.S. State Department issued a travel alert about China‘s anti-flu measures that have led to some travelers being quarantined for a week, sometimes under unsanitary conditions and without the ability to communicate with others.”[141]

    Actions concerning pigs

    Virus source and name

    Experts agree that the new virus is a type of swine influenza, derived originally from a strain that lived in pigs.[142] This origin gave rise to the common name of “swine flu”, largely used by mass media. Despite this origin, however, the current strain is transmitted between people and not from swine.[128]

    Pork import bans

    International health officials have reaffirmed that pork is safe to eat and hogs are not to blame for the epidemic. However, as of early June, ChinaRussia and more than a dozen other countries were still banning pork imports from the U.S. The World Trade Organisation (WTO) planned to highlight the pork bans in a forthcoming report on protectionism and reiterate that cooked pork is not a source of infection and is safe to eat.[143] Some U.S. officials speculated that the bans may be more about “market share than health concerns,” and were costing the hog industry millions of dollars every week.[144]

    As a result, by mid-August, pork had become the second-worst commodity investment of 2009, and may fall 33 percent by yearend. U.S. exports plunged 20 percent in the first half of 2009 and are heading for the first annual decline since 1990. Tyson Foods Inc. idled slaughterhouses, and U.S. hog farmers haven’t been profitable in a year. Imports from the U.S. fell 38 percent in Russia this year and 73 percent in China, including Hong Kong, USDA data show.[145]


    In June the U.S. Agriculture Department said it would launch a pilot surveillance project to look for new strains of flu virus in pigs. Some experts claim that global health officials have underestimated the risk that pig herds might be a source of new influenza strains but have instead focused on the threat of bird flu.[146]

    Contingency planning

    Global outbreak expected

    In late August, WHO predicted an “explosion” of swine flu cases during the remainder of 2009 and into 2010. Because the global spread of swine flu will endanger more lives as it speeds up in coming months, they are alerting governments to boost preparations for a swift response. “There will soon be a period of further global spread of the virus, and most countries may see swine flu cases double every three to four days for several months until peak transmission is reached,” said WHO’s Shin Young-soo. But it is in developing countries where the accelerated spread of swine flu poses the greatest threat as it places underequipped and underfunded health systems under severe strain, Shin said.[147]

    Although most flu symptoms are mild and last only a few days without treatment, health officials worldwide are also concerned because the virus is new and could easily mutate and become more virulent. To combat the virus, WHO and the U.S. government are gearing up for a massive vaccination campaign later this year, one not seen since Jonas Salk discovered the polio vaccine in 1955 and distributed worldwide.[148] Officials are also urging communities, businesses and individuals to make contingency plans for possible school closures, multiple employee absences for illness, surges of patients in hospitals and other effects of potentially widespread outbreaks.[149] Ann Schuchat of the CDC estimates that as many as 40% of the workforce, in a worst-case scenario, might be unable to work at the peak of the pandemic due to the need for many healthy adults to stay home and care for an ill family member,[150] stressing that individuals “need to be ready, to be thinking ahead” and have steps in place should a workplace close down or a situation arise that requires working from home.[151]

    A survey of Americans done in late June by the Harvard School of Public Health found that roughly 90 percent said they would be “willing to avoid shopping malls, movie theaters, public transportation and worship services for more than two weeks if health officials told them to.” It also found that parents were worried about closures of schools or day care centers, with 43 percent saying they would lose pay or have money problems if they had to stay home a week or more because they were sick or had to care for someone.[152] In the U.K. the government established a National Pandemic Flu Service with a hotline and website, enabling persons with symptoms to get advice or obtain drugs without first getting a prescription from a doctor.[153]

    An opinion article by specialist Eric Toner in the New York Times notes that if the 2009 flu follows patterns from earlier pandemics, the U.S. may experience a much bigger, second wave of the pandemic early in the fall, perhaps before a vaccine is widely available, and advised preparations to avoid crowding of hospital emergency departments. It suggests that patients with mild symptoms should be told that flu can usually be treated by home care with rest, fluids, and acetaminophen and ibuprofen for fever, while suggesting alternative treatment options including extended physician and clinic hours and special flu clinics run by volunteers. It advised hospitals to cancel vacations, reassign personnel, require mandatory overtime, and to pool resources and patient loads.[154]


    The U.S. Department of Health and Human Services (HHS) and the Centers for Disease Control and Prevention (CDC), with input from the U.S. Department of Homeland Security (DHS), has developed updated guidance for employers of all sizes to use as they develop or review and update plans to respond to 2009 H1N1 influenza now and during the upcoming fall and winter influenza season.

    These guidelines, posted on their website along with a video, recommend that all employers balance a variety of objectives when determining how best to decrease the spread of influenza and lower the impact of influenza in the workplace. “They should consider and communicate their objectives, which may include one or more of the following: (a) reducing transmission among staff, (b) protecting people who are at increased risk of influenza related complications from getting infected with influenza, (c) maintaining business operations, and (d) minimizing adverse effects on other entities in their supply chains.” [155]


    In California, school districts and universities are on alert and working with health officials to launch education campaigns. Many plan to stockpile medical supplies and discuss worst-case scenarios, including plans to provide lessons and meals for low-income children in case elementary and secondary schools close. University of California campuses are already stockpiling supplies, from paper masks and hand sanitizer to food and water, and are considering screening students for fever when they check into dorms.[156] The CDC has also advised that schools set aside a room for people developing flu-like symptoms while they wait to go home and that surgical masks be used for ill students or staff and those caring for them.[157] To help prepare for contingencies, some medical experts in the U.S. suggest that every county should create an “influenza action team” to be run by the local health department, parents, and school administrators.[158]

    School closures to be avoided

    David Persse, public health authority for the city of Houston, says that “School closure is an ineffective strategy. It appears that the virus spreads so quickly and effectively among kids that by the time you close the schools it’s too late.” Instead, the CDC recommends that students and school workers with flu symptoms should stay home for seven days, and those who are sick longer shouldn’t come back to school until 24 hours after symptoms subside. There is awareness that the CDC’s “seven-days-at-home-with-one-caregiver advice” will put some families in a financial bind.[159] But the CDC guidelines noted that everything could change if the outbreak suddenly turns severe. In those cases, the agency said, some schools may need to be closed, and certain precautions—for example, spacing school desks farther apart—might need to be imposed.[157]

    Colleges and universities

    In the U.S. the Department of Health and Human Services (HHS), Department of Education (ED) and the Centers for Disease Control and Prevention (CDC) have published new guidelines along with a “Toolkit” for Institutions of Higher Education (IHE) to plan for and respond to the upcoming flu season. Government officials are especially concerned because the virus appears to disproportionately affect young people between ages 6 months to 24 years of age, making them one of the top priority groups when it comes to the new H1N1 vaccine.

    The new guidelines provide a menu of strategies to keep learning facilities open while reducing exposure of students, faculty, and staff to the flu. “It is imperative that the public and private sector work together to reach students with critical information about the flu and teach them what to do when the flu hits their dorm room, fraternity house, or campus classroom.” The new guidelines also state that the most important actions are to encourage and facilitate good hand washing and covering coughs and sneezes; to encourage flu vaccination for recommended groups when vaccine becomes available; and to separate sick people from well people as soon as possible. [160]

    The CDC recommends that colleges should consider suspending classes this fall if the flu virus begins to cause “severe illness in a significantly larger share of students than last spring.” They have also urged schools to suspend any rules, including penalizing late papers or missed classes, or requiring a doctor’s note, to prevent students from venturing out while ill.[161]


    The president of the Association of Flight Attendants told members of a U.S. Congressional subcommittee that all flight attendants should be given training in how to handle a person with flu and help in communicating to passengers the importance of keeping clean hands. She also said that flight attendants need to be provided gloves and facemasks to deal with flu-stricken passengers. Other medical experts add that airlines should also ensure that passenger cabins are always properly ventilated, including during any flight delays in which passengers are kept aboard the plane. But they also add that although the aviation industry in the U.S., along with the CDC, have tried to reassure passengers that air travel is safe, they have so far done too little to try to limit infection risks. One expert noted that “there seem to be no public announcements or printed bulletins in most airports,” or on the web sites of airlines and travel vendors.[162]

    Virus characteristics

    The virus is a novel strain of influenza. Existing vaccines against seasonal flu provide no protection, and there is no vaccine for this strain. A study at the U.S. Centers for Disease Control and Prevention published in May 2009 found that children had no preexisting immunity to the new strain but that adults, particularly those over 60, had some degree of immunity. Children showed no cross-reactive antibody reaction to the new strain, adults aged 18 to 64 had 6-9%, and older adults 33%.[163][164] It was also determined that the strain contained genes from four different flu viruses: North American swine influenza, North American avian influenza, human influenza, and two swine influenza viruses typically found in Asia and Europe. Further analysis showed that several of the proteins of the virus are most similar to strains that cause mild symptoms in humans, leading virologist Wendy Barclay to suggest on May 1 that the initial indications are that the virus was unlikely to cause severe symptoms for most people.[165] Scientists in Winnipeg completed the first full genetic sequencing of the virus on 6 May.[166]

    Virus origins

    On June 23, the New York Times reported that U.S. federal agriculture officials, “contrary to the popular assumption that the new swine flu pandemic arose on factory farms in Mexico,” now believe that it “most likely emerged in pigs in Asia, but then traveled to North America in a human.” They emphasized that there was no way to prove their theory, but stated that there is no evidence that this new virus, which combines Eurasian and North American genes, has ever circulated in North American pigs, “while there is tantalizing evidence that a closely related ‘sister virus’ has circulated in Asia.”[128]

    In early June 2009, using computational methods developed over the last ten years at Oxford, Dr Oliver Pybus of Oxford University’s Department of Zoology and his team attempted to reconstruct the origins and timescale of the 2009 flu pandemic. He claims “Our results show that this strain has been circulating among pigs, possibly among multiple continents, for many years prior to its transmission to humans.” The research team that worked on this report also believe that it was “derived from several viruses circulating in swine,” and that the initial transmission to humans occurred several months before recognition of the outbreak. The team concluded that “despite widespread influenza surveillance in humans, the lack of systematic swine surveillance allowed for the undetected persistence and evolution of this potentially pandemic strain for many years.”[167]

    Structure of the influenza virion. The hemagglutinin (HA) andneuraminidase (NA) proteins are shown on the surface of the particle. The viral RNAs that make up thegenome are shown as red coils inside the particle and bound to ribonucleoproteins (RNPs).

    According to the researchers, movement of live pigs between Eurasia and North America “seems to have facilitated the mixing of diverse swine influenza viruses, leading to the multiple reassortment events associated with the genesis of the (new H1N1) strain.” They also stated that this new pandemic “provides further evidence of the role of domestic pigs in the ecosystem of influenza A.”[122] Some experts also suspect that a leading cause of the new virus outbreak is insufficient surveillance by the pork industry and the fact that “animal husbandry now more closely resembles the petrochemical industry than the happy family farm”[168]

    Estimates of total cases

    On July 24, Keiji Fukuda, WHO’s Assistant Director-General for Health Security and Environment said the pandemic was still in its early stages globally and two billion infections over the course of the pandemic was “a reasonable ballpark to be looking at.”[169]On the same day, the Anne Schuchat, director of the U.S. CDC’s National Center for Immunization and Respiratory Diseases, estimated that without a swine flu vaccine, current trends suggest 12% to 24% of Americans might get swine flu this fall and winter. But if large enough numbers of people get the vaccine before the next waves of the pandemic sweep the nation it would “put a dent in the pandemic,” she said. Initial availability of vaccines is expected by mid-October, although healhcare workers and people most at risk would likely get them first.[170]

    As for the current totals, in early July WHO officials gave up trying to count the number of cases, saying the best they can do is estimate the spread of the “unstoppable” virus. And the CDC’s Schuchat declined even to hazard a guess, saying it was “more than a million.” Officials do not have the tools they need to count, she pointed out. “Most people who have respiratory illnesses don’t find out exactly what caused it. Even most people with influenza don’t know exactly which type of influenza caused their illness.”[171]

    In late June, the CDC estimated that 1 million Americans had so far contracted the flu. By comparison, an estimated 15 million to 60 million Americans are infected with the seasonal flu each year, leading to roughly 36,000 deaths.[172] According to the CDC, however, only about one in 20 cases was being officially reported in the U.S. in late May.[173] In the U.K., some experts thought the number of cases was potentially 300 times more than early published estimates,[174] warning that case estimates by the U.K. and other governments were “meaningless” and hiding its true extent. There were also estimates that Japan may have had approximately 30,000 cases by late May.[174]


    The CDC has noted that most infections continue to be mild, similar to seasonal flu, and that recovery tends to be fairly quick.[175] Some experts point out that the deaths so far are “a tiny fraction” of people who die every year from seasonal flu – with barely a public murmur.” One doctor said that “when there’s something that’s new and unknown, it scares people.”[176] Some medical journalists suggest that the news media may be overreacting to the new virus and have not compared its virulence with that of the regular “seasonal” flu.[177]

    Mutation potential

    On May 22, 2009, WHO chief Dr. Margaret Chan said that the virus must be closely monitored in the southern hemisphere, as it could mix with ordinary seasonal influenza and change in unpredictable ways. “In cases where the H1N1 virus is widespread and circulating within the general community, countries must expect to see more cases of severe and fatal infections,” she said. “[178] Experts writing in the July New England Journal of Medicine note that “historically, pandemic viruses have evolved between seasons, and the current strain may become more severe or transmissible in the coming months.” They therefore stress that “international cooperation will be crucial” to engage in proper surveillance to help monitor changes in the virus’s behavior, which will aid in both “vaccine targeting” and interpreting illness patterns in the fall of 2009.[130]

    Other experts are also concerned that the new virus strain could mutate over the coming months. Guan Yi, a leading virologist from the University of Hong Kong, for instance, described the new H1N1 influenza virus as “very unstable”, meaning it could mix and swap genetic material when exposed to other viruses. During an interview he said “Both H1N1 and H5N1 are unstable so the chances of them exchanging genetic material are higher, whereas a stable (seasonal flu) virus is less likely to take on genetic material.” The H5N1 virus is mostly limited to birds, but in rare cases when it infects humans it has a mortality rate of between 60% to 70%.[179] Experts worry about the emergence of a hybrid of the more virulent Asian-lineage HPAI (highly pathogenic avian influenza) A/H5N1 strain (media labeled “bird flu”) with more human-transmissible Influenza A strains such as this novel 2009 swine-origin A/H1N1 strain (media labeled “swine flu”), especially since the H5N1 strain is and has been for years endemic in birds in countries like ChinaIndonesiaVietnam and Egypt.[179][180] (See the suite of H5N1 articles for details.)

    Nor had federal health officials in the U.S. dismissed the possibility that the worst was yet to come. “Far from it,” Ann Schuchat of the CDC says, noting that the horrific 1918 flu epidemic, which killed hundreds of thousands in the United States alone, was preceded by a mild “herald” wave of cases in the spring, followed by devastating waves of illness in the autumn. “That 1918 experience is in our minds,” she said.[181]

    As of late July, U.S. health officials said that the swine flu “isn’t yet mutating to become more dangerous,” but they are closely tracking that as the virus continues to circle the globe.[182]

    Infection among animals


    Before being transmitted to humans, the viruses have circulated in swine which has allowed for the undetected persistence and evolution of this potentially pandemic strain for many years.


    In late August, the government of Chile discovered that the swine flu virus had jumped to birds, “opening a new chapter in the global epidemic.” Top flu and animal-health experts with WHO and the CDC were monitoring the situation closely, but said the infected turkeys have suffered only mild effects, easing concern about a potentially dangerous development. Chile’s turkey meat remains safe to eat, they said, and so far there have been no signs of a potentially dangerous mutation.[183]

    Pandemic declared

    On June 11, 2009, the WHO‘s Chan declared the outbreak had become a pandemic.[185] The WHO declared a Pandemic Alert Level of six, out of a maximum six, describing the degree to which the virus had been able to spread among humans. In the same briefing, Chan stressed that the WHO pandemic level was not linked to severity. On a separate scale for severity, WHO assessed the global severity as “moderate.”[185]

    WHO had hesitated to raise its alert level and declare a phase 6 pandemic as the virus to date has caused generally mild symptoms, even though the pandemic level describes spread of the virus rather than its severity. Having raised it to level 6 may cause many countries to adopt a variety of plans, such as shutting borders, banning events and curtailing travel. A move to phase 6 means that “emergency plans are instantly triggered around the globe.” In addition, at phase 6, many pharmaceutical companies may switch from making seasonal flu shots to pandemic-specific vaccine, “potentially creating shortages of an immunization to counter the normal winter flu season.”[173] Keiji Fukuda, WHO’s assistant director general of health security and environment, stated that a move to phase 6 would “signify a really substantial increase in risk of harm to people.” He also cautioned that “one of the critical issues is that we do not want people to over-panic if they hear that we are in a pandemic situation.”

    WHO to focus on developing countries

    On June 12, the day after the pandemic was declared, WHO stated that its “primary concern is to strengthen and support health systems in countries with less resources.” It emphasized that developing countries, where medical care systems are weak and supplies of antivirals insufficient, “will be the frontline of their battle against pandemic flu.” They also noted that the virus has so far caused mostly mild symptoms in rich countries such as Canada and the United States, with “most patients recovering without even going to a doctor.” But WHO experts felt that it could prove far more deadly to poor populations “already weakened by malnutrition, chronic conditions like asthma and diabetes, or low immunity due to HIV/AIDS.” They were also working to make stocks of antivirals and antibiotics and an eventual pandemic vaccine more accessible and affordable to developing countries.[186]

    Northern Hemisphere

    As of early July 2009, the flu has been reported in more than 100 countries, mostly in the Northern Hemisphere, with the United States reporting the most cases — more than 43,000, including at least 380 deaths, according to the World Health Organization.

    As of May 30, 2009, seasonal flu is down, circulating at low levels; while the non-seasonal new H1N1 flu strain continues to spread and constitutes approximately 82% of all influenza viruses reported to CDC in the last week of May 2009.[187]

    Southern Hemisphere

    In July 2009 WHO stated “The countries are seeing a mixed picture depending on the country. For example, in Chile, it was just reported that over 99% of their influenza viruses are the new pandemic H1N1 virus. By contrast, in Australia, they see more of a mixed picture, where they are seeing both the pandemic H1N1 virus but they are also seeing a seasonal H3N2 virus that circulates there. Then, if we go down to South Africa, right now the seasonal influenza viruses are much more predominant than the pandemic influenza viruses. In the Southern Hemisphere, it is fair to say that there is a mixed picture. In another month or so, we will have again a much clearer picture about how the pandemic virus is spreading in the Southern Hemisphere and whether it is beginning to crowd out the seasonal influenza viruses in many countries or in just some countries.”[188]

    It is predicted that the virus will likely continue to spread worldwide, especially in the Southern Hemisphere, where countries are in the winter months and the traditional flu season.[189] As of 20 August 2009 South America have had more than 35,000 laboratory-confirmed cases mostly in Chile,ArgentinaPerú and Brazil; and more than 1,150 deaths mostly in Brazil and Argentina. Keiji Fukuda of WHO has stated that swine flu has already caused more infections than seasonal influenza at the start of Chile’s winter flu season.[190][191] On June 19, 2009 Chilean health authorities stated that many mild cases were not being laboratory-confirmed and were treated like seasonal influenza, so reported cases are an underestimate.[192]. Additionally, as of August 20, 2009 the total number of reported flu cases that fit the definition of the new virus but has not necessary been laboratory-confirmed has reached 353,525.[12]. On the other hand, the virus has been reported to be decreasing on mostly of the country, and unchanged on the rest.[12]

    On June 6, 2009, Australia‘s second largest city, Melbourne, was reported to be the “swine flu capital of the world”;[193] on 9 July there were 1,876 cases in Victoria, including 11 deaths, mostly in Melbourne. However, according to professor Robert Booy from the University of Sydney, the reason Victoria has the highest per capita rate of swine flu in the world “may simply be down to Australia’s tough testing regime,” and “is probably the best in the world at detecting this influenza virus.” As a result, he feels that the U.S. and Mexico probably had more cases than have been reported, stating “I would be quite certain that there’s ten to a hundredfold more cases in the U.S. than are confirmed.[194] In early June WHO and the U.S. Food and Drug Administration suggested that one of the testing methods used in Australia gives only a “presumptive positive” rather than a “definitive positive” result for H1N1 influenza and is only about 90 percent accurate. As a result, they stated that some Australians may have been given a false diagnosis.[195]

    In late June, swine flu was also detected in pigs at a farm near Buenos AiresArgentina, but health officials there said the virus has not shown itself to be any deadlier to the animals than a normal flu. About a quarter of pigs at the farm were found to be infected, and veterinarians there are “very worried because humans are infecting the animals.” However, officials added that eating pork poses no danger to people. The discovery comes during winter in Argentina and the country is already experiencing a human swine flu outbreak with a death toll higher than any other country in South America.[196] On July 3, the Argentinian health minister, Juan Manzur, admitted that, since the start of the outbreak, there have been over 100,000 cases, causing at least 52 confirmed deaths.[197]

    In August, 2009, the first death in South Africa from Swine Flu was reported, a 22 year old man who died in late July.[198]

    Symptoms and expected severity

    Video xo.ogv

    CDC’s CAPT Dr. Joe Bresee describes symptoms.

    The signs of infection with swine flu are similar to other forms of influenza, and include a fevercoughingheadaches, pain in the muscles or jointssore throatchillsfatigue and runny noseDiarrheavomiting and neurological problems have also been reported in some cases.[105][199][200][201] A study concluded on May 5, published in the New England Journal of Medicine, found that 94% of confirmed patients had fever and 92% had cough.[202] People at higher risk of serious complications included people age 65 years and older, children younger than 5 years old, pregnant women, and people of any age with underlying medical conditions, such as asthma, diabetes, obesity, heart disease, or a weakened immune system (e.g., taking immunosuppressive medications or infected with HIV).[200][203] According to the CDC, more than 70% of hospitalizations in the U.S. have been people with such underlying conditions.[204]

    Most cases mild

    Evidence mounted through May 2009 that the symptoms were milder than health officials initially feared. As of May 27, 2009, most of the 342 confirmed cases in New York City had been mild and there had been only 23 confirmed deaths from the virus.[205]Similarly, Japan has reported 1,048, mostly mild flu cases, and no deaths,[206] with the government reopening schools as of May 23, stating that the “virus should be considered more like a seasonal flu.”[207] In Mexico, where the outbreak began in April, Mexico City officials lowered their swine flu alert level as no new cases had been reported for a week.[208]

    Symptoms that may require medical attention

    Certain symptoms may require emergency medical attention. In children signs of respiratory distress, for instance, those might include blue lips and skindehydration, rapid breathing, excessive sleepingseizures[209] and significant irritability that includes a lack of desire to be held. In adults, shortness of breath, pain in the chest or abdomen, sudden dizziness or confusion may indicate the need for emergency care. In both children and adults, persistent vomiting or the return of flu-like symptoms that include a fever and cough may require medical attention.[200]

    Underlying conditions may worsen symptoms

    WHO reported that almost one-half of the patients hospitalized in the United States had underlying conditions.[210] “Among 30 patients hospitalized in California,” stated the WHO report, “64 percent had underlying conditions and two of five pregnant women developed complications, including spontaneous abortion and premature rupture of membranes.” And on June 5, health officials in six states that reported deaths from swine flu said that all six patients had been diagnosed with other health problems.[211]

    However, doctors in New York suggested that people with “underlying conditions” who had flu symptoms should consult their doctors first. “Visiting an emergency room full of sick people may actually put them in more danger,” wrote the New York Times. Dr. Steven J. Davidson, the chairman of emergency medicine department at Maimonides Medical Center in Brooklyn commented “Like the asthmatics, we’d really prefer that pregnant women would stay away from the emergency departments.” Approximately one-third of New Yorkers have one of the underlying conditions recognized by the city.[203] However, no statistics for people with underlying conditions who die from seasonal flu have been reported by the media thus far.


    Influenza infection can cause pneumonia leading to death. This is typically described as either viral pneumonia, which has a rapid onset, often within one day after infection, or bacterial pneumonia, which often begins a week after infection after symptoms have begun to subside.[212]

    Viral pneumonia has sometimes been attributed to “cytokine storm“, in which an overly active immune response damages the lungs. Reports of deaths among healthy young people during the first weeks of the 2009 flu pandemic were attributed to this cause.[213]

    Bacterial pneumonia is a secondary infection resulting from a weakened ability to clear common bacteria from the lower lungs, combined with reduced alveolar macrophage activity which makes it more difficult for the body to fight infection. Bacteria that cause pneumonia include Pneumococcus,Staphylococcus, and Hemophilus influenzae.[214] Bacterial pneumonia has been credited for a large proportion of deaths in the 1918 flu pandemic.[215]

    Recent data has suggested that these two forms of pneumonia are not entirely unrelated. A study of 37,000 children in South Africa who received a pneumococcal vaccine (PncCV) found that they were on average one-third less likely to suffer viral pneumonia following infections with seven different respiratory viruses, as well as being protected from bacterial pneumonia afterward.[216]


    Personal hygiene

    The Mayo Clinic has suggested personal measures to avoid seasonal flu infection which should be applicable to the 2009 pandemic: vaccination when available, thorough and frequent hand-washing, a balanced diet with fresh fruits and vegetables, whole grains, and lean protein, sufficient sleep, regular exercise, and avoiding crowds.[217]

    Airborne virus prevention

    Masks may be of benefit in “crowded settings” or for people who are in “close contact” with infected persons, defined as 1 meter or less by the World Health Organization and 6 feet or less by the U.S. Occupational Safety and Health Administration. In these cases the CDC recommended respirators classified as N95, but it is unknown whether they would prevent swine flu infection.[218] According to mask manufacturer 3M, there are no “established exposure limits for biological agents” such as swine flu virus.

    The UK Health Protection Agency considers facial masks unnecessary for the general public[219] and some experts feel it may lead to a false sense of security. Masks are not generally provided by airport security or airlines although the CDC recommends the use of surgical masks in some circumstances.[220] other U.S. officials stated in May that if the flu virus does in fact reach pandemic proportions, “there won’t be enough face masks to go around.”[221] A recent internal CDC briefing noted, “20,000 people die from novel 2009-H1N1 and everybody wants to wear a mask. 9 million people die from AIDS and no one wants to wear a condom.”[222]

    Pork safe to eat

    The leading international health agencies stressed that the “influenza viruses are not known to be transmissible to people through eating processed pork or other food products derived from pigs.”[223]

    Airline hygiene precautions

    U.S. airlines have made no major changes as of the beginning of June, but continued standing practices that include looking for passengers with symptoms of flu, measles or other infections, and rely on in-flight air filters to ensure that aircraft are sanitized. “We take our guidance from the professionals (such as the CDC)”, stated an Air Transport Association spokesman. The CDC has not recommended that airline crews wear face masks or disposable overcoats. Alaska Airlines removed all pillows and blankets from its fleet in late April/early May.[224]

    Outside the U.S. however, some airlines have modified hygiene procedures to minimize travel health risks on international flights. Asian carriers have stepped up cabin cleaning, installed state-of-the-art air filters and allowed in-flight staff to wear face masks, with some replacing used pillows, blankets, headset covers and headrest covers, while others have begun disinfecting the cabins of all aircraft. In China, some airline flight attendants are required to wear disposable facial masks, gloves and hats and even disposable overcoats during flights to select destinations.[225]

    Singapore has been thermal-screening everyone coming into the country, with Singapore Airlines giving passengers traveling to the United States health kits that include a thermometer, masks and antiseptic towels. Its cabin and flight crews are getting mandatory temperature checks before flights. The government recently quarantined a passenger who was later found to have the flu along with about 60 other people on the same flight who were sitting within three rows.[225] A consultant for the microbiology division at National University Hospital in Singapore, said hygiene practices such as covering the nose and mouth when sneezing or coughing in confined areas may be the best way to limit infection and safety measures such as costly air filters may be of limited use for carriers.[225]


    Chinese inspectors on an airplane, checking passengers for fevers, a common symptom of swine flu

    On April 28, 2009, WHO’s Dr. Keiji Fukuda said that it was too late to contain the swine flu. “Containment is not a feasible operation. Countries should now focus on mitigating the effect of the virus,” he said.[226] He therefore did not recommend closing borders or restricting travel, stating that “with the virus being widespread… closing borders or restricting travel really has very little effects in stopping the movement of this virus.”[226] However, on April 28, the U.S. CDC began “recommending that people avoid non-essential travel to Mexico.”[227] Many other countries confirmed that inbound international passengers would be screened. Typical airport health screening involves asking passengers which countries they have visited and checking whether they feel or appear particularly unwell. Thermographic equipment was put into use at a number of airports to screen passengers.[228] A number of countries also advised against travel to known affected regions, while experts suggested that if those infected stay at home or seek medical care, public meeting places are closed, and anti-flu medications are made widely available, then in simulations the sickness is reduced by nearly two-thirds.[229]


    Some countries began quarantining foreign visitors suspected of having or being in contact with others who may have been infected.

    Travel alerts for People’s Republic of China

    In late May 2009, the Chinese government confined 21 U.S. students and three teachers to their hotel rooms because a passenger on their plane to People’s Republic of China, suspected of having swine flu, had been seated within four rows of the students.[230]As a result, on June 22, the U.S. State Department issued a travel alert about China‘s anti-flu measures, and is warning travelers that PR China is “imposing the seven-day quarantine on passengers arriving with a fever or flu-like symptoms” in order to prevent the flu spreading in the country. “Although the proportion of arriving Americans being quarantined remains low, the random nature of the selection process increases the uncertainty surrounding travel to China,” the State Department stated on June 22. “The selection process focuses on those sitting in close proximity to another traveler exhibiting fever or flu-like symptoms or on those displaying an elevated temperature if arriving from an area where outbreaks of 2009-H1N1 have occurred. We have reports of passengers arriving from areas where outbreaks have occurred (including the U.S. and Mexico) being placed in precautionary quarantine simply because they registered slightly elevated temperatures,” said the State Department. In some cases, parents and children have been separated if a parent or child tested positive for the swine-flu virus. “This situation presents the possibility ofChinese medical personnel administering medications to minors without first having consulted their parents,” said the travel alert.[141]

    The State Department also said it had “received reports about unsuitable quarantine conditions, including the unavailability of suitable drinking water and food, unsanitary conditions, and the inability to communicate with others.” All travelers to China, including U.S. citizens, are obliged to follow local public health-related measures, and there’s no compensation for lost travel expenses. Travelers to China should consider buying travel insurance to protect against losses in case they are quarantined, recommended the State Department.[141][231]

    On June 8, 2009 China reported that New Orleans Mayor Ray Nagin, his wife and a security guard, although symptom free, were being held in quarantine after flying on a plane carrying a passenger who exhibited symptoms. Nagin was traveling to China and Australia on an economic development trip. However, according to Fox News, “they don’t even allow phone calls,” reporting that the Chinese were also screening his calls “to keep him safe,” and have refused even to pass on telephone messages without the permission of government health officials.[232]

    Other government quarantines

    Other governments have taken or threatened similar quarantine actions: In Hong Kong, an entire hotel was quarantined with 240 guests after one person staying there was found to have swine flu.[233]

    The government of Australia ordered a cruise ship with 2000 passengers to stay at sea because of a swine flu threat;[234] Egyptians who went on the annual Muslim pilgrimage to Mecca risked being quarantined upon their return.[235]

    At the end of April 2009, when the outbreak began, Russia and Taiwan said they would quarantine visitors showing symptoms of the virus,[236] and in Southern California, a marine confirmed to have swine flu was placed in quarantine along with about 30 other Marines.[237] In early May, Japanquarantined 47 airline passengers in a hotel for a week after three travelers who arrived on the same plane from Canada tested positive for H1N1 swine flu,[238] and Mongolia quarantined 109 Russian airline passengers in Ulaanbaatar.[239]

    In India, after four airline passengers from London tested positive, the government ordered that all the 231 passengers of the flight should be administered the anti viral drug oseltamivir. Health authorities also asked that all the passengers not move out of their homes until further orders and quarantined at least one of the infected passengers.[240] And in Egypt, a foreign students’ dormitory for the American University in Cairo, with 140 students, was put under quarantine after two U.S. students were diagnosed with swine flu.[241][242] According to the BBC, police wearing face masks “stood at barriers outside the elegant seven-floor AUC dormitory in Zamalek,” and pizzas were delivered to the building during the day but none of the residents were allowed in or out.[243]

    Other governments have given health officials the “increased power” to order people into quarantine to control the spread of swine flu. The government of New Zealand, for instance, gave medical officers the power to order people to be quarantined at home if they have been in close contact with someone who has swine flu.[244]

    Pre-screening advisories by some governments

    Some governments have also suggested pre-screening “outbound” passengers from countries that are thought to have a high rate of infection. India‘s Minister of State for Health, for example, said on June 16, that there should be “some kind of screening” for outbound travellers in the U.S., claiming that most people coming from that country have been tested positive for influenza A(H1N1) virus. As of July 2009, 509 people have tested positive for swine flu in India. [245] Of them, most had come from the U.S. “The U.S. is the main source (of swine flu) as far as India is concerned,” the health minister stated, adding that “the government is ready to handle the situation and there is no need to panic.”[246]

    School closures


    The early days of the swine flu outbreak led to numerous school closures in a number of states. However, with signs that the virus was milder than initially feared, schools reopened and the closures stopped, although officials accept that the virus is continuing to spread nationwide.

    In California, school administrators have noted that throughout the U.S. during the early weeks in the swine flu outbreak, counties recommended that schools close if a student was infected, but since early May, as the virus spread widely across the state and country, public health experts agreed that closing schools wasn’t helping contain the disease. It’s not yet known whether school closures will remain relatively rare or whether more will close before summer break begins, as many schools point out that closures could become more problematic, with finals and graduations coming up.[247]

    In New York City, more than 50 public schools were closed for short periods since early May, and as of June 5, 2009, with 780 confirmed cases in the state, the majority of cases have been mild. However, attendance dropped at other schools as worried parents kept their children home. As of early June, a few schools were still closed.[248] Similarly, 858 Texas schools had also closed during the outbreak with most now reopened. And in Connecticut school officials are debating the value of keeping schools closed, with 480 confirmed cases and most of them mild. There, if more than 15 percent of the pupils had flu-like symptoms, the school would be advised to close.[249]


    A small number of schools have been closed with some to provide schoolwork via the websites, email and mail, however some school administrators have noted major inconveniences. One principal stated “We needed this like a hole in the head for our year 11 and 12 students — their exams start on June 15, 2009 and that’s just six days away.”[250] Schools in New South Wales have also been known to forbid students to return to school for 7 days if they have visited urban Victoria.


    Some college classes were postponed for a week.[251]

    Hong Kong

    The Hong Kong government has announced that all nurseries, kindergartens and primary schools in Hong Kong would not be opening for the rest of the 2008-2009 school year.[252][253] However, the 2009-2010 school year would begin normally.


    The Ministry of Health has advised that schools close from June 15 until June 30 to prevent the spread of the A(H1N1) virus among children.[254] In Argentina, the government authorized districts to extend the 2009 winter school holidays by up to two weeks, in order to avoid the spread of influenza among students.[255] Holidays would be, in these districts, one month long.

    Costa Rica

    The Ministry of Health announced that schools would close until June 27 to prevent the spread of the A(H1N1) virus among children.[256] That made the vacations last a month. The Ministry of Health also announced that if schools opened before the Department of Health let them, they would close the school.[257]

    United Kingdom

    The Department of Health has said that to stop the virus affecting so many children, some schools would have to close after the Summer Break.


    Schools are closed now (August 10, 2009) in many cities Like PuneMumbaiNew Delhi etc. In Pune Multiplexes are also closed for 7–10 days and are currently closed.

    Spread in the workplace

    The CDC advised sick people to stay home from work, school, or social gatherings and to generally limit contact with others to avoid infecting them.

    In the UK, the HSE has also issued general guidance for employers[258]


    WHO does not expect the swine flu vaccine to be widely available until the end of 2009, noting that current production “yield” was only about half as much as expected and would cause timeline delays.[259] Vaccine producers can normally produce about a billion doses of any single vaccine each year and as a result WHO anticipates a “global shortfall,” Keiji Fukuda said in May.[260] In the U.S. initial quantities of vaccine will become available in mid-October and the CDC recommends that the first doses should go to priority groups such as pregnant women, people who live with or care for babies under six months old, children six months to four years old and health-care workers.[261] [262]

    Although WHO reports that a fully licensed vaccine might not be ready until the end of 2009, some experts feel that with “little or no safety data about a swine flu vaccine,” governments that are planning to roll out mass campaigns are “taking a gamble,” since any rare side effects won’t show up until millions of people start getting the shots.[262] Nonetheless, in late July, some European countries were planning to accelerate the approval process for the vaccine, and countries like Britain, Greece, France and Sweden all say that they will start using the vaccine once it is given approval, which could happen within weeks. Some European officials feel that “the benefit of saving lives is worth the gamble,” and are letting companies skip testing large groups of people before the vaccine is approved. The U.S. is taking a more cautious approach, however.[263]

    U.S. and local health officials are monitoring the Southern Hemisphere, where the “virus is already on an unstoppable course” and where it’s feared it might combine with the seasonal flu strain and develop drug resistance.[264]

    Although the seasonal flu vaccine provides little or no protection against H1N1 swine flu, health experts recommend immunization to help prevent people from being infected with both at once. “Vaccination against seasonal influenza should begin as soon as vaccine is available and continue throughout the influenza season,” the CDC’s Anne Schuchat said, and wants 83 percent of the population to get an annual flu vaccine,” noting that only 40 percent of the U.S. population received one last year.[265]

    Two injections will be required three weeks apart for the swine flu and a third will be needed for seasonal flu to provide maximum immunity. Children younger than 9 years old will need four shots.[266] The CDC plans to administer the vaccine through clinics set up by state health organizations, but some experts feel that health departments are under-funded and could get “fatigued.”[266]



    The experts agree that children who are sick should be kept home, especially if they’re running flu-like symptoms such as high fever, vomiting or diarrhea. They should also be kept away from other children. While most experts suggest seeking medical care if a child becomes sick, they also stress not to take children with flu-like symptoms to the emergency department. “That’s the worst thing. They may not have swine flu but they could get it [there],” one expert stated. Instead of rushing to the emergency department, “people need to call their physicians or call a hotline.” They also state that any child who has been sick should be fever-free for at least 24 hours (without the aid of medications) before returning to school.[157]

    Home treatment remedies

    The Mayo Clinic and Medline list a number of ways to help ease symptoms, including adequate liquid intake and rest, soup to ease congestion, and over-the-counter drugs to relieve pain. Aspirin, for instance, “is very effective for treating fever in adults” [267] although in children and adolescents, aspirin is not usually given due to the risk of Reye’s syndrome. While over-the-counter drugs relieve symptoms, they do not kill the virus. Most patients were expected to recover without medical attention, although those with pre-existing or underlying medical conditions were more prone to complications.

    Antiviral drugs

    Recommended usage and availability

    According to the CDC, antiviral drugs can be given to treat those who become severely ill, two of which are recommended for swine flu symptoms: oseltamivir (Tamiflu) and zanamivir (Relenza). To be most useful, they must be taken within 2 days of showing symptoms. They work by deactivating an enzyme the virus needs to grow and spread. Therefore, when taken soon after symptoms are noticed, “they may shorten the illness by a day or so,” according to the Mayo Clinic. Oseltamivir is an oral medication, but zanamivir is inhaled through a device similar to an asthma inhaler and shouldn’t be used by anyone with respiratory conditions, such as asthma and lung disease.

    Furthermore, as the flu spreads, there could be temporary shortages of these drugs. The U.S. CDC therefore recommends Tamiflu treatment primarily for people hospitalized with swine flu; people at risk of serious flu complications due to underlying medical conditions; patients at risk of serious flu complications because they are pregnant, under age 5, or over age 65; and to prevent infection of people at risk of serious flu complications who have been exposed to someone with swine flu. WHO likewise recommends that Tamiflu only be given to particularly vulnerable people but notes that healthy people who catch mild to moderate cases of swine flu don’t need the drug at all.

    Anti-viral resistance risk

    The CDC has warned that the indiscriminate use of antiviral medications to prevent and treat influenza could ease the way for drug-resistant strains to emerge which would make the fight against a pandemic that much harder. In addition, a British report found that people often fail to complete a full course of the drug which also encourages resistance. Just as with antibiotics, of central importance to antivirals’ success is taking them properly, including completing the recommended course. The U.S. government has issued detailed guidelines on prescribing antivirals but are concerned that health professionals may not follow the recommendations or may give in to patients who pester them for prescriptions.

    Possible side effects

    Both medications can cause side effects, including lightheadedness, nausea, vomiting, loss of appetite and trouble breathing and it is recommended that patients discuss possible side effects with their doctor before starting any antiviral medication. The Food and Drug Administration (FDA) has required the maker of Tamiflu to include a warning that people with the flu, particularly children, may be at increased risk of self-injury and confusion after taking Tamiflu and that individuals with the flu who take Tamiflu be closely monitored for signs of unusual behavior. A study done in the U.K. during July found more than half of the children reported side effects, such as nausea, stomach cramps and trouble sleeping. Almost one in five reported a neuropsychiatric side effect, such as poor concentration, confusion or bad dreams.

    Warnings of online purchasing

    When buying these medications, some agencies warn against buying from online sources, with WHO estimating that half the drugs sold by online pharmacies without a physical address are counterfeit.

    Emergency planning

    Emergency preparedness experts suggest that organizations, such as corporations, should be making plans now in case something big and unexpected happens with the Swine Flu or other potential pandemic viruses. Kevin Nixon, an emergency planning expert who has testified before Congress and served on the Disaster Recovery Workgroup for the Office of Homeland Security, and the Federal Trade Commission, stresses that private companies “should be hammering out a game plan for who would do what and where if the government decided to restrict our movements to contain an outbreak.” He states that “companies and employers that have not done so are being urged to establish a business continuity plan should the government direct state and local governments to immediately enforce their community containment plans.”

    Emergency planning would include some of the following: Asking people with symptoms, and members of an ill person’s household, to voluntarily remain at home for up to 7 days; sending students home from school, including public and private schools as well as colleges and universities, and recommending out-of-school social distancing; and recommending social distancing of adults which could include cancelling public gatherings or changing workplace environments.

    Crime risk

    In early June, the Australian Crime Commission, in a written public report, warned that criminals may exploit a swine flu pandemic. They pointed out that illicit markets, robbery and fraud through false charities were all potential targets for organised crime, and the emergence of a black market for medicine was also a concern. “Criminal groups may also seek to infiltrate legitimate markets such as transport, finance and government sectors to help facilitate criminal activity and confuse the line between their illegal and legal activities,” the report said. It warns of potential robbery and extortion, counterfeit medicine scams, black markets, charity fraud, welfare fraud and possibly increased community influence.” Industrial drug sites might be targeted for robbery along with retail chemists. During a polio outbreak in 1959, for instance, “masked bandits” stole 75,000 Salk vaccine shots from a Montreal university research center.

    In late May, the U.S. Food and Drug Administration (FDA) uncovered a “surge of phony swine flu treatments” available on the Internet. They have reportedly ordered dozens of Web site operators to stop making fraudulent claims. In the six weeks since FDA’s campaign began the number of new sites selling fake swine flu treatments and protective devices has plummeted, whereas at the beginning they were seeing as many as 10 new Web sites a day selling fraudulent products.

    Data reporting and accuracy

    Influenza surveillance information “answers the questions of where, when, and what influenza viruses are circulating. It can be used to determine if influenza activity is increasing or decreasing, but cannot be used to ascertain how many people have become ill with influenza”. Estimating deaths from influenza is also a complicated process. In 2005 influenza only appeared on the death certificates of 1,812 people (USA only). The average annual toll from flu is, however, estimated to be 36,000 (USA only). The CDC explains that “…influenza is infrequently listed on death certificates of people who die from flu-related complications.” and furthermore that “Only counting deaths where influenza was included on a death certificate would be a gross underestimation of influenza’s true impact.”

    The last WHO update, issued on July 6, showed 94,512 confirmed cases in 122 countries, with 429 deaths. Many epidemiologists have pointed out that, in reality, millions of people have had swine flu, usually in a mild form, so the numbers of laboratory-confirmed cases were actually meaningless. Partly as a result, on July 16, WHO announced that it “will no longer issue the global tables showing the numbers of confirmed cases for all countries”. Instead, national health authorities from all countries should inform WHO on a weekly basis of their qualitative assessment of the geographical spread, trend of cases, intensity of disease, impact on the health‐care system, and deaths.

    In the U.S. as of July 17, the number of confirmed infections was 40,617, with 263 deaths, according to the CDC. But the agency believes that more than one million people have been infected and weren’t tested for the virus or didn’t visit a doctor. Since the disease has now become so widespread, the CDC says it too will “probably” suspend counting cases within the next few weeks and focus instead on tracking clusters, severe cases, deaths and other unusual events.

    Early reports

    The initial outbreak received a week of near-constant media attention. Epidemiologists cautioned that the number of cases reported in the early days of an outbreak can be very inaccurate and deceptive due to several causes, among them selection bias, media bias, and incorrect reporting by governments. Inaccuracies could also be caused by authorities in different countries looking at differing population groups. Furthermore, countries with poor health care systems and older laboratory facilities may take longer to identify or report cases.

    The CDC in late May stated that counting confirmed cases had become “largely irrelevant,” and switched instead to its traditional surveillance systems for monitoring flu-like symptoms by looking for patterns, clusters and changes in flu activity nationwide. According to the CDC, surveillance methods, along with rapid isolation and treatment, only makes sense at the very earliest stage of an outbreak, and “becomes irrelevant” once the virus is spreading widely within the community, as it is in the United States.

    In some instances, governments accused other countries of intentionally underreporting cases. Moscow, for instance, hinted that the Dominican Republic was under-reporting cases to “boost tourism.”  In early May, Cuba’s Fidel Castro accused Mexico of hiding the scope of the epidemic until after President Obama visited the country in April.

    In the U.S. data accuracy has also become an issue, with some school districts deciding to keep the names of students and schools that have reported infections confidential, one stating that “it would not be fair to single out one school,” since doing so would be likely to trigger requests by parents to have their children tested despite their health not being in danger, and the schools lacking the ability to test everyone. Dr. Hector Gonzalez, Director of the Laredo Health Department, said that according to CDC guidelines, physicians only need to submit samples for testing if the patient is a child under 5 years of age, is pregnant, has an underlying medical condition or is suffering from respiratory distress requiring urgent care.