The 2009 flu pandemic or swine flu is an influenza pandemic, and the second of two pandemics involving the H1N1 influenza virus (the first of which became the 1918 flu pandemic), although in new version. First described in April 2009, the virus emerged as a new strain of H1N1 produced when the reassortment of avian, pig, and human flu viruses was previously combined with the Eurasian swine flu virus, leading to the term "swine flu".
Unlike most strains of influenza, H1N1 does not disproportionately infect adults older than 60 years; this is an unusual and distinctive feature of the H1N1 pandemic. Even in the case of previously very healthy people, a small proportion will develop pneumonia or acute respiratory distress syndrome (ARDS). It manifests itself as an increase in difficulty breathing and usually occurs 3-6 days after the onset of early flu symptoms. Pneumonia caused by flu can be a direct viral inflammation or secondary bacterial pneumonia. In fact, an article written in November 2009 New England Journal of Medicine recommends that chest X-ray patients show pneumonia receiving both antiviral and antibiotics. In particular, it is a warning sign if a child (and possibly an adult) appears to be better and then recurs with a high fever, because this recurrence may be bacterial pneumonia.
Video 2009 flu pandemic
History
Originally called the "epidemic", the widespread H1N1 infection was first recognized in the state of Veracruz, Mexico, with evidence that the virus had been present for months before it was officially called an "epidemic". The Mexican government closes most public and private facilities in Mexico City in an effort to prevent the spread of the virus; However, it continues to spread globally, and clinics in some areas are overwhelmed by infected people. In late April, the World Health Organization (WHO) announced "the first public health emergency of international concern", or PHEIC, and in June the WHO and the US CDC stopped counting cases and declared the outbreak a pandemic.
Although informally called "swine flu", the H1N1 flu virus can not be spread by eating pork or pork products; similar to other influenza viruses, are usually contracted by person to person transmission through the respiratory tract. Symptoms usually last 4-6 days. Antiviral (oseltamivir or zanamivir) is recommended for those with more severe symptoms or those in risk groups.
The pandemic began to taper in November 2009, and by May 2010, the number of cases had fallen sharply. On August 10, 2010, WHO Director-General Margaret Chan announced the end of the H1N1 pandemic, and announced that the H1N1 influenza event had entered a post-pandemic period. According to the latest WHO statistics (as of July 2010), the virus has killed more than 18,000 people since it appeared in April 2009, but they state that the total deaths (including unconfirmed or unreported deaths) of the H1N1 strain are "undoubtedly higher. " "Critics claim the WHO has exaggerated the dangers, spreading" fear and confusion "rather than" direct information. "WHO began an investigation to determine whether it was" an unnecessary fear. "A flu follow-up study conducted in September 2010 found that "the risks of the most serious complications do not increase in adults or children." In the August 5, 2011 article PLoS ONE , the researchers estimate that the 2009 H1N1 global infection rate is 11% to 21% lower than previously thought, but in 2012, research showed that as many as 579,000 people could be killed by the disease, since only casualties were confirmed by laboratory testing included in the original number, and meant that many of them had no access to health facilities are not counted.The majority of these deaths occur in Africa and Southeast Asia.Experts, including the WHO, have agreed that a estimated 284,500 people were killed by the disease, much higher than the initial death toll.
Maps 2009 flu pandemic
Classification
Early outbreaks are called "H1N1 influenza", or "Swine Flu" by American media. This is called the H1N1/09 pandemic virus by WHO, while the US Centers for Disease Control and Prevention calls it "novel influenza A (H1N1)" or "H1N1 flu 2009". In the Netherlands, originally called "Swine Flu", it is now called "New Influenza A (H1N1)" by national health agencies, although the media and the general population use the name "Mexican Flu". South Korea and Israel are briefly considered to call it the "Mexican virus". Then, the South Korean press uses "SI", short for "swine influenza". Taiwan suggested the names of "H1N1 flu" or "new flu", adopted by most local media. The World Organization for Animal Health proposes the name "North American influenza". The European Commission adopted the term "new flu virus".
Signs and symptoms
The symptoms of H1N1 flu are similar to other influenza, and may include fever, cough (usually "dry cough"), headache, muscle or joint pain, sore throat, chills, fatigue, and colds. Diarrhea, vomiting, and neurological problems have also been reported in some cases. Higher-risk people experience serious complications including those over 65, children younger than 5, children with neurodevelopmental conditions, pregnant women (especially during the third trimester), and people from all age with underlying medical conditions, such as asthma, diabetes, obesity, heart disease, or a weakened immune system (eg, taking immunosuppressive or HIV-infected drugs). More than 70% of hospitalizations in the US are people with underlying conditions, according to the CDC.
In September 2009, the CDC reported that the H1N1 flu "seems to take more severe casualties among chronically ill children than the usual seasonal flu." Through August 8, 2009, the CDC has received 36 child mortality reports with influenza-related symptoms and laboratory confirmed pandemic H1N1 from state and local health authorities in the United States, with 22 of these children having neurodevelopmental conditions such as cerebral palsy, muscular dystrophy, or procrastination delay. "Children with nervous and muscular problems may be at very high risk for complications because they can not cough hard enough to clear their airways". From April 26, 2009, to February 13, 2010, the CDC has received reports of the deaths of 277 children with confirmed influenza A (H1N1) in laboratories in the United States.
Severe case
The World Health Organization reports that the clinical picture in severe cases is very different from the pattern of illness seen during seasonal influenza epidemics. While people with certain underlying medical conditions are known to be at increased risk, many severe cases occur in previously healthy people. In severe cases, patients generally begin to deteriorate about three to five days after the onset of symptoms. Rapid deterioration, with many patients experiencing respiratory failure within 24 hours, requires immediate admission to the intensive care unit. After admission, most patients require immediate respiratory assistance with mechanical ventilation.
Complications
Most complications have occurred among previously healthy individuals, with obesity and respiratory disease being the strongest risk factor. Pulmonary complications are common. Primary influenza pneumonia occurs most commonly in adults and can progress rapidly into acute lung injury requiring mechanical ventilation. Secondary bacterial infection is more common in children. Staphylococcus aureus , including the methicillin-resistant strain, is an important cause of secondary bacterial pneumonia with a high mortality rate; streptococcus pneumoniae is the second most important cause of secondary bacterial pneumonia for children and primary for adults. Neuromuscular and cardiac complications are unusual but can occur.
UK investigation of risk factors for hospitalization and adverse outcome with an influenza A/H1N1 pandemic saw 631 patients from 55 infected hospital admitted confirmed from May to September 2009. 13% were treated in high dependence or intensive care unit and 5% died; 36% of aged & lt; 16 years and 5% are> 65 years old. Non-white and pregnant patients are over-represented. 45% of patients have at least one underlying condition, especially asthma, and 13% receive antiviral drugs before admission. Of the 349 chest X-rays documented at admission, 29% had evidence of pneumonia, but co-infection coins were rare. Multivariate analysis showed that obesity noted by physicians at admission and lung conditions other than asthma or chronic obstructive pulmonary disease (COPD) was associated with severe outcomes, such as radiologically confirmed pneumonia and increased levels of C-reactive protein (> = < span> 100 mg/l) . 59% of all hospital deaths occur in previously healthy people.
Fulminant myocarditis (suddenly) has been associated with infection with H1N1, with at least four confirmed cases of myocarditis in patients also infected with A/H1N1. Three of the four cases of H1N1-related myocarditis were classified as fulminant, and one patient died. Also, there appears to be a link between severe A/H1N1 influenza infection and pulmonary embolism. In one report, five of the 14 patients treated in the intensive care unit with severe A/H1N1 infection were found to have pulmonary embolism.
An article published in JAMA in September 2010 challenged previous reports and stated that infected children in the 2009 flu pandemic were no more likely to be hospitalized with complications or acquired pneumonia than those who captured the strain seasonal. The researchers found that about 1.5% of children with H1N1 swine flu strain were hospitalized within 30 days, compared with 3.7% of those who were sick with seasonal strains of H1N1 and 3.1% with H3N2 virus.
Diagnosis
The confirmed diagnosis of H1N1 flu pandemic requires testing of nasopharyngeal, nasal or oropharyngeal swabs from patients. Real-time RT-PCR is a recommended test because the others can not distinguish between H1N1 pandemic and regular seasonal flu. However, most people with flu symptoms do not need a test for a special H1N1 flu pandemic, as the test results usually do not affect the recommended treatment. The US CDC recommends testing only for people hospitalized with suspected flu, pregnant women and people with weakened immune systems. For the diagnosis of influenza and not a special H1N1 flu pandemic, more tests are available including rapid influenza diagnostic tests (RIDT), which produce results in about 30 minutes, and direct and indirect immunofluorescence tests (DFA and IFA), which take 2-4 hour. Due to the high rate of false negative RIDT, the CDC recommends that patients with disease compatible with new influenza A (H1N1) virus infection but with negative RIDT results should be treated empirically based on clinical suspicion, underlying medical conditions, disease severity and risk of complications, and if a more definitive determination of infection with influenza virus is required, testing with rRT-PCR or viral isolation should be performed. Rhonda Medows of the Georgia Department of Public Health stated that rapid tests are not exactly anywhere from 30% to 90% of the time and warn doctors in his state not to use them because they are so often wrong. The use of RIDT has also been questioned by researcher Paul Schreckenberger of the Loyola University Health System, which suggests that rapid tests can actually pose a dangerous public health risk. WHO's Nikki Shindo has expressed regret at a delayed treatment report pending H1N1 test results and suggests, "[D] ocor does not have to wait for laboratory confirmation but makes a diagnosis based on clinical and epidemiological background and initiates initial treatment".
On June 22, 2010, the CDC announced a new test called "CDC Influenza 2009 A (H1N1) PMR Real-Time RT-PCR Panel (IVD)". He used molecular biology techniques to detect influenza A viruses and especially the 2009 H1N1 virus. The new test will replace the previous real-time RT-PCR diagnostic tests used during the 2009 H1N1 pandemic, which received emergency authorization authorizations from the US Food and Drug Administration in April 2009. Test results are available in four hours and 96% exact.
Cause
The virus was found as a new strain of influenza in which the existing vaccine against seasonal flu provides little protection. A study at the US Centers for Disease Control and Prevention published in May 2009 found that children do not have pre-existing immunity, but adults, especially those over 60, have a certain level of immunity. Children did not show cross-reactive antibody reactions to new strains, adults ages 18 to 60 had 6-9%, and older adults 33%. While it has been thought that these findings suggest partial immunity in older adults probably because of previous exposure to the same seasonal influenza virus, a study in November 2009 of unvaccinated populations in rural China found only 0.3% cross-antibody reactions reactive to H1N1 strains, suggesting that previous vaccinations for seasonal flu and not exposure may have resulted in immunity found in older US populations.
Analysis of the genetic sequence of the first isolates, immediately distributed in the GISAID database by Nature and WHO, promptly determined that the strain contained genes from five different flu viruses: North American swine flu, North American avian flu, human influenza and two swine influenza viruses usually found in Asia and Europe. Further analysis has shown that some proteins from viruses most closely resemble those that cause mild symptoms in humans, leading virologist Wendy Barclay to suggest on May 1, 2009, that early indications are that the virus is unlikely to cause severe symptoms for most people..
Viruses are currently less lethal than previous pandemic strains and kill about 0.01-0.03% of those infected; 1918 influenza is about a hundred times more deadly and has a case-fatality rate of 2-3%. On November 14, 2009, the virus infected one in six Americans with 200,000 hospitalizations and 10,000 deaths - due to hospitalization and fewer deaths than the average overall flu season, but with a much higher risk for those under 50 year. With the deaths of 1,100 children and 7,500 adults 18 to 64, these numbers are "much higher than in the regular flu season".
In June 2010, scientists from Hong Kong reported the discovery of a new swine flu virus that is a hybrid of the pandemic H1N1 virus and a virus previously found in pigs. This is the first report of a pandemic viral reassortment, which in humans has slowly evolved. Nancy Cox, head of the influenza division at the US Centers for Disease Control and Prevention, said, "This paper is very interesting because it shows for the first time what we feared at the beginning of the pandemic, and that is that this particular virus, when put into pigs, can do reassort with the resident virus in pigs and we will have a new gene constellation and bingo, here we are. "Pigs have been referred to as flu vein mixers because they can be infected by the avian flu virus, which rarely directly infects people, and by human viruses. When pigs are simultaneously infected with more than one virus, the virus can exchange genes, producing new variants that can be transmitted to humans and sometimes spread among them. "Unlike the situation with birds and humans, we have a situation with pigs and humans where there are two paths of virus exchange, with pigs very much a two-way street".
Transmission
The spread of the H1N1 virus is thought to occur in the same way as seasonal flu spreads. The flu virus spreads mainly from person to person through coughing or sneezing by people with influenza. Sometimes people can get infected by touching something - like a surface or an object - with a flu virus on it and then touching their face. "Avoid touching eyes, nose or mouth. Germs spread this way".
The number of basic reproductions (the average number of others for which every infected individual will infect, in populations that have no immunity to the disease) for the 2009 novel H1N1 is estimated at 1.75. A study in December 2009 found that the transmisibility of influenza H1N1 virus in households was lower than that seen in past pandemics. Most of the transmission occurs immediately before or after the onset of symptoms.
The H1N1 virus has been transmitted to animals, including pigs, turkeys, weasels, domestic cats, at least one dog and a cheetah.
Prevention
The H1N1 vaccine was initially limited and in the US CDC recommends that the initial dose should be given to priority groups such as pregnant women, people living with or treating infants under six months of age, children aged six months to four years and health workers. In the UK, the NHS recommends priority vaccines for people over six months who are clinically at risk for seasonal flu, pregnant women and households with compromised immunity.
Although it was initially thought that two injections would be required, clinical trials show that the new vaccine protects adults "with only one dose, not two," and thus a limited supply of vaccines will be twice as far as predicted. Health officials around the world are also concerned because the virus is new and can easily mutate and become more virulent, although most flu symptoms are mild and last only a few days without treatment. Officials also urged communities, businesses and individuals to make contingency plans for possible school closures, absence of several employees due to illness, surges in hospital patients and other effects of a potentially widespread outbreak.
In February 2010, the CDC Advisory Committee on Immunization Practices voted for a "universal" flu vaccine in the US to include all persons over the age of six months. The 2010-2011 vaccine will protect against the 2009 H1N1 pandemic virus and two other flu viruses.
Public health response
On April 27, 2009, EU health commissioners advised Europeans to postpone unimportant trips to the United States or Mexico. It follows the first confirmed case discovery in Spain. On May 6, 2009, the Canadian Public Health Agency announced that its National Microbiology Laboratory (NML) has mapped the genetic code of the swine flu virus, the first time it has been done. In the UK, the National Health Service launched the website, the National Flu Pandemic Service, which allows patients to self-assess and obtain authorization numbers for antiviral drugs. This system is expected to reduce the burden of general practitioners.
US officials observed that six years of concern about H5N1 bird flu did not prepare much for the current H1N1 flu epidemic, noting that after H5N1 emerged in Asia, it eventually killed about 60% of the several hundred people infected with it over the years, many countries took steps to prevent a similar crisis spread further. The CDC and other US government agencies use a summer break to take stock of US responses to the H1N1 flu and work to patch up the gaps in public health safety nets before the flu season begins in early autumn. Preparation includes planning a second influenza vaccination program in addition to seasonal influenza, and improving coordination between federal, state and local government and private healthcare providers. On October 24, 2009, US President Obama declared swine flu as a national emergency, giving the Secretary of Health and Human Services Kathleen Sebelius the authority to grant relief to request the hospital from the usual federal requirements.
Vaccines
On 19 November 2009, vaccine doses have been given in more than 16 countries. A 2009 review by the US National Institutes of Health (NIH) concluded that 2009 H1N1 vaccine has a safety profile similar to that of seasonal vaccines.
In 2011, a study from US Vaccine Effectiveness Network estimates the overall effectiveness of all pandemic H1N1 vaccines at 56%. A CDC study released Jan. 28, 2013, estimates that the H1N1 Pandemic vaccine saves about 300 lives and prevents about 1 million diseases in the US. The study concluded that vaccination programs started 2 weeks earlier, nearly 60% more cases could be prevented. This study is based on effectiveness in preventing cases, admissions, and deaths of 62% for all subgroups except those over 65, whose effectiveness is estimated at 43%. The effectiveness is based on European and Asian studies and expert opinion. [3] Delays in vaccine administration show a lack of world capacity for vaccine production, as well as problems with international distribution. Some producers and rich countries have concerns about obligations and regulations, as well as transport logistics, storage, and vaccine donations to donate to poor countries.
Alleged conflicts of interest
In January 2010, Wolfgang Wodarg, a German-trained physician and currently leading the health committee at the Council of Europe, claimed major companies had organized a "panic campaign" to pressure the World Health Organization to declare a "false pandemic" to sell vaccine. Wodarg said the WHO "false pandemic" flu campaign was "one of the biggest drug scandals of the century". He said the "fake pandemic" campaign began in May 2009 in Mexico City, when a hundred or so "normal" reported influenza cases expressed as a threatening new pandemic start, although he said there was little scientific evidence for this.. Nevertheless, he argues that the WHO, "in collaboration with several major pharmaceutical companies and their scientists, redefined the pandemic", abolished the claim that "a large number of people have contracted the disease or died" of the existing definition and replaced it by stating simply that there is a virus, it spreads outside the border and people have no immunity.
WHO responded by stating that they took their duty to give independent advice seriously and be guarded against interference from outside interests. Announcing the WHO's action review, spokesman Fadela Chaib stated: "Criticism is part of the epidemic cycle, we expect and welcome the criticism and opportunity to discuss it". In March 2010, the European Council launched an investigation into the "influence of pharmaceutical companies on the global swine flu campaign", and preliminary reports are being prepared.
On April 12, 2010, Keiji Fukuda, WHO's top influenza expert, stated that the system leading to the pandemic declaration caused confusion about H1N1 circulating around the world, and she expressed concern that there was a failure to communicate in relation to the uncertainty about the new virus, deadly as feared. WHO Director-General Margaret Chan has appointed 29 influenza experts from outside the organization to conduct an overview of WHO's H1N1 flu pandemic handling. He has told them, "We want to review our honest, critical, transparent, credible and independent performance".
In June 2010, Fiona Godlee, editor in chief of BMJ , published an editorial criticizing the WHO, saying that investigations have revealed that some experts advising WHO about pandemics have financial ties with drug companies producing antiviral and vaccine. Margaret Chan, WHO Director-General, replied, "Without question, the BMJ and editorial features will leave many readers with the impression that the WHO's decision to declare a pandemic is at least partially influenced by the desire to increase the pharmaceutical industry's profits. , is that the decision to raise the pandemic alert level is based on clearly defined virological and epidemiological criteria.It is difficult to bend this criterion, no matter what the motive is.
Infection control
Travel precautions
On May 7, 2009, the WHO stated that detention is not feasible and that countries should focus on reducing the effects of the virus. They do not recommend closing the border or restrict travel. On April 26, 2009, the Chinese government announced that returning visitors from flu-affected areas within two weeks would be quarantined.
The US carrier made no major changes in early June 2009, but continued its prevailing practices including seeking passengers with symptoms of flu, measles or other infections, and relying on airborne air filters to ensure that the aircraft is cleaned. Masks are generally not provided by airlines and CDC does not recommend the crew to wear them. Some non-US carriers, mostly Asian, including Singapore Airlines, China Eastern Airlines, China Southern Airlines, Cathay Pacific and Aeromexico, took steps such as improving cabin cleaning, installing sophisticated air filters, and allowing in-flight staff to wear masks face.
According to research conducted in Australia and Japan, screening individuals for influenza symptoms at airports during the 2009 H1N1 outbreak is not an effective infection control method.
School
US government officials are very concerned about schools because the H1N1 flu virus seems to disproportionately affect young people and school age, between six months and 24 years. The H1N1 outbreak led to a number of preventive school closures in some areas. Instead of closing school, the CDC recommends that students and school workers with flu symptoms should stay home for a total of seven days, or up to 24 hours after the symptoms subside, whichever is longer. The CDC also recommends that colleges should consider suspending fallow classes in 2009 if the virus starts causing severe illness in a much larger section of students than the previous spring. They also urge schools to suspend regulations, such as penalties for late papers or missed classes or requirements for doctors' notes, to uphold "self-isolation" and prevent students from leaving while sick; schools are advised to set aside space for people who develop flu-like symptoms as they wait to get home and have sick students or staff and those who care for them using face masks.
In California, the school and university districts are on alert and working with health officials to launch educational campaigns. Many plan to stockpile medical supplies and discuss worst-case scenarios, including plans to provide lessons and meals for low-income children if primary and secondary schools are closed. University of California campus stockpiles supplies, from paper masks and hand sanitizers to food and water. To help prepare for the possibility, University of Maryland Maryland pediatric professor of medicine, James C. King Jr. suggest that each region should create an "influenza action team" to be run by local health departments, parents and school administrators. On October 28, 2009, about 600 schools in the United States were temporarily closed, affecting more than 126,000 students in 19 states.
Workplace
Afraid of the worst-case scenario, the US Department of Health and Human Services (HHS), the Centers for Disease Control and Prevention, and the Department of Homeland Security (DHS) developed the latest guides and videos for employers use as they develop plans to respond to the H1N1 outbreak. It recommends that employers consider and communicate their goals, such as reducing transmission among staff, protecting people at high risk of influenza-related complications from being infected, maintaining business operations, and minimizing adverse effects on other entities in their supply chain.
The CDC estimates that as many as 40% of the workforce may not be working at the peak of the pandemic because of the need for many healthy adults to stay home and care for sick family members, and suggest that individuals should have steps in place of workplace should be closed or situations arise that require working from home. The CDC further recommends that people at work should stay in the hospital for seven days after the flu, or 24 hours after the symptoms end, whichever is longer.
In the UK, the Health and Safety Executive (HSE) also issued general guidelines for employers.
Facial mask
The US CDC does not recommend the use of face masks or respirators in non-health care settings, such as schools, workplaces or public places, with a few exceptions: people who are sick with viruses around people, and sick people at risk for severe disease while taking care of someone with flu. There are some disagreements about the value of wearing face masks, some experts fear that masks can give people a sense of security that is wrong and should not substitute for other standard precautions. Masks can be beneficial for people who are in close contact with an infected person, but it is unknown whether they prevent the H1N1 flu infection. Yukihiro Nishiyama, professor of virology at Nagoya University Medical School, commented that the mask "is better than nothing, but it is difficult to completely block airborne viruses as it can easily escape the gap".
According to a 3M mask manufacturer, the mask will filter the particles in an industrial setting, but "no exposure limits are set for biological agents such as swine flu viruses". However, despite the lack of evidence of effectiveness, the use of such masks is common in Asia. They are very popular in Japan, where hygiene and hygiene is highly valued and where ethics requires those who are ill to wear masks to avoid spreading the disease.
Quarantine
During the heightened fears of a pandemic, some countries initiate or threaten to initiate quarantine of foreign visitors suspected of having or in connection with others who may have been infected. In May 2009, the Chinese government restricted 21 US students and three teachers to their hotel rooms. As a result, the US State Department issued a travel alert about China's anti-flu measures and warned travelers not to travel to China if sick. In Hong Kong, the entire hotel is quarantined with 240 guests; Australia ordered a cruise ship with 2,000 passengers to stay at sea due to swine flu threat. Egyptian Muslims who make an annual pilgrimage to Mecca are at risk of being quarantined after they return. Russia and Taiwan say they will quarantine visitors with fever coming from areas where the flu is present. Japan quarantined 47 plane passengers at a hotel for a week in mid-May, then in mid-June India advised pre-screening passengers "out" from countries suspected of having high infection rates.
Pork and food safety
The pandemic virus is a type of swine flu, derived from a strain that lives in pigs, and this origin brings out the common name of "swine flu". This term is widely used by the mass media. This virus has been found in American pigs, and Canadians as well as pigs in Northern Ireland, Argentina, and Norway. Leading health agencies and the US Secretary of Agriculture have stressed that eating properly cooked pork or other food products derived from pigs will not cause the flu. However, on April 27, Azerbaijan imposed a ban on imports of livestock products from across America. The Indonesian government has also stopped the import of pigs and initiated the inspection of the pigs 9 million in Indonesia. The Egyptian government ordered the slaughter of all pigs in Egypt on April 29, 2009.
Treatment
A number of methods have been recommended to help relieve symptoms, including adequate fluid intake and rest. Over-the-counter pain medications such as acetaminophen and ibuprofen do not kill the virus; However, they may be useful for reducing symptoms. Aspirin and other salicylate products should not be used by people under 16 with any flu-like symptoms due to the risk of Reye's Syndrome.
If the fever is mild and there are no other complications, fever medication is not recommended. Most people recover without medical care, although those with existing or underlying medical conditions are more susceptible to complications and may benefit from further treatment.
People in the at-risk group should be treated with antiviral (oseltamivir or zanamivir) as soon as possible when they first experience flu symptoms. Risk groups include pregnant women and postpartum women, children under two years, and people with underlying conditions such as respiratory problems. People who are not in a risk group who have symptoms that deteriorate continuously or rapidly should also be treated with antiviral. People who have developed pneumonia should be given both antiviral and antibiotics, as in many severe cases of disease caused by H1N1, bacterial infections develop. Antiviral is most useful if given within 48 hours of the onset of symptoms and may improve outcomes in hospitalized patients. In those aged over 48 hours who suffer from moderate or severe pain, antiviral drugs may still be useful. If oseltamivir (Tamiflu) is unavailable or unusable, zanamivir (Relenza) is recommended as a substitute. Peramivir is an experimental antiviral drug approved for inpatients in cases where other available treatment methods are ineffective or unavailable.
To help avoid the shortage of these drugs, the US CDC recommends oseltamivir treatment especially for people hospitalized with a flu pandemic; people at risk of serious flu complications due to underlying medical conditions; and patients at risk for serious flu complications. The CDC warns that the indiscriminate use of antiviral drugs to prevent and treat influenza may ease the way for drug-resistant strains to emerge, which will make the war against the pandemic much more difficult. In addition, a British report found that people often fail to complete a full course of drugs or take medication when it is not needed.
Side effects
Both drugs have known side effects, including a mild headache, chills, nausea, vomiting, loss of appetite and difficulty in breathing. Children reported an increased risk of self-injury and confusion after taking oseltamivir. WHO warns against buying antiviral drugs from online sources, and estimates that half the drugs sold by online pharmacies without a physical address are fake.
Resistance
In December 2012, 2010, the World Health Organization (WHO) reported 314 samples of the 2009 H1N1 flu pandemic tested worldwide have shown resistance to oseltamivir (Tamiflu). This is not completely unexpected because 99.6% of the seasonal H1N1 flu strains tested have developed resistance to oseltamivir. There is no circulating flu that indicates resistance to zanamivir (Relenza), other available anti-virus.
On December 8, 2009, the Cochrane Collaboration, which reviewed medical evidence, announced in a published review in BMJ that it has reversed earlier findings that oseltamivir (Tamiflu) and zanamivir (Relenza) antiviral drugs can counteract pneumonia and other serious conditions associated with influenza. They reported that analysis of 20 studies showed oseltamivir offered mild benefits for healthy adults if taken within 24 hours after onset of symptoms, but found no clear evidence that it prevented lower respiratory tract infections or other influenza complications. Their published findings relate only to their use in healthy adults with influenza; they say nothing about their use to patients who are considered at high risk for complications (pregnant women, under-fives and those with underlying medical conditions), and uncertainty over its role in reducing complications in healthy adults may still leave it as a drug useful. to reduce the duration of symptoms. Drugs may eventually prove effective against flu-related complications; in general, Cochrane Collaboration concluded "Paucity of good data".
Some specific results from BMJ articles include: "The efficacy of oral oseltamivir against symptomatic laboratory confirmation influenza was 61% (risk ratio 0.39, 95% confidence interval 0.18 to 0.85) in 75 mg daily... The remaining evidence suggests oseltamivir does not reduce respiratory complications associated with influenza related (risk ratio 0.55, 95% confidence interval 0.22 to 1.35) ". Note especially the wide reach for this second result.
Epidemiology
Although it is not known exactly where or when the virus originated, analysis in scientific journals has suggested that the H1N1 strain responsible for the 2009 outbreak first evolved in September 2008 and circulated among humans for several months before being officially recognized and identified as a new strain. influenza.
Mexico
The virus was first reported to two US children in March 2009, but health officials have reported that it appeared to infect people in early January 2009 in Mexico. This outbreak was first detected in Mexico City on March 18, 2009; immediately after the outbreak was officially announced, Mexico notified the US and the World Health Organization, and within days of the Mexico City outbreak "effectively closed". Some countries cancel flights to Mexico while others stop trading. Call to close the border to keep the spread refused. Mexico already has hundreds of non-lethal cases before the epidemic is officially discovered, and is therefore in the midst of a "silent epidemic". As a result, Mexico reported only the most serious cases showing signs that were more severe than those of the common cold, possibly leading to a preliminary estimate of the incidence of mortality cases.
United States
The new strain was first identified by the CDC in two children, none of whom had ever had contact with pigs. The first case, from San Diego County, California, was confirmed from a clinical specimen (nasopharyngeal swab) examined by the CDC on April 14, 2009. The second case, from Imperial County, California, was confirmed on 17 April. Patients in the first confirmed case experienced flu symptoms including fever and cough on clinical examination on March 30, and the second on 28 March.
The confirmed first confirmed H1N1/09 flu pandemic outbreak, occurring at Texas Children's Hospital in Houston, Texas, was a toddler from Mexico City who visited family in Brownsville, Texas, before being admitted to Houston for treatment.
Data reporting and accuracy
Influenza surveillance information "answers the question of where, when, and what influenza viruses are circulating.Sharing of such information is essential during a pandemic such as April 2009, when the genetic sequence of the early viruses is quickly and openly shared through the GISAID Initiative within days identification plays a key role in facilitating an early response to a growing pandemic.Supervision is used to determine whether influenza activity is increasing or decreasing, but it can not be used to ascertain how many people are ill with influenza ". For example, at the end of June 2009, influenza surveillance information showed that the United States had nearly 28,000 laboratory confirmed cases including 3,065 hospitalizations and 127 deaths; but mathematical modeling shows an estimated <1 million Americans currently have a 2009 flu pandemic, according to Lyn Finelli, a flu surveillance officer with CDC. Estimating deaths from influenza is also a complicated process. In 2005, influenza only appeared on the death certificate of 1,812 people in the US. The average annual US death toll from flu is estimated at 36,000. The CDC explains: "[I] nfluenza is rarely listed on death certificates of people who die from flu-related complications" and therefore, "Just counting the deaths in which influenza is inserted on a death certificate would be too underestimating the true impact of influenza".
Influenza surveillance information on the 2009 H1N1 flu pandemic is available, but hardly any studies attempt to estimate the total number of deaths caused by H1N1 flu. Two studies were conducted by the CDC; Later they estimated that between 7.070 and 13,930 deaths were caused by H1N1 flu from April to November 14, 2009. During the same period, 1642 deaths were formally confirmed as caused by H1N1 flu. WHO states that the total deaths (including unconfirmed or unreported deaths) of the H1N1 flu is "no doubt higher" than their confirmed mortality statistics.
The initial outbreak received weeks of almost constant media attention. Epidemiologists warn that the number of cases reported in the early days of the outbreak can be extremely inaccurate and deceptive, due to several causes, including selection bias, media bias and false reporting by the government. Inaccuracies can also be caused by authorities in different countries who observe different groups of people. In addition, countries with poor health care systems and older laboratory facilities may take longer to identify or report cases. "[E] ven in developed countries [the number of flu deaths] is uncertain, because medical authorities usually do not verify who actually died of influenza and who died of flu-like illness". Joseph S. Bresee (head of the epidemiology of the CDC flu division) and Michael Osterholm (director of the Center for Infectious Disease Research and Policy) have shown that millions of people have been exposed to the H1N1 flu, usually in a mild form, so the number of laboratories Confirmed cases are virtually meaningless, and in July 2009, WHO stopped counting the number of individual cases and focused more on major outbreaks.
Followup
A study in Wisconsin published in the Journal of the American Medical Association in September 2010, reported that the findings show that the 2009 H1N1 flu is no worse than the seasonal flu. "The most serious risk of complications does not increase in adults or children," the study authors wrote. "Children are disproportionately affected by H1N1 infection in 2009, but the severity of perceived symptoms and the risk of serious outcomes does not increase." Infected children in the 2009 H1N1 flu pandemic are no more likely to be hospitalized with complications or exposed to pneumonia than those who catch seasonal strains. About 1.5% of children with the H1N1 swine flu strain were hospitalized within 30 days, compared with 3.7% of those with a seasonal H1N1 strain and 3.1% with the H3N2 virus.
CDC's disease and death estimates from April 2009 to April 2010, in the US are as follows:
- The CDC estimates that between 43 million and 89 million cases of 2009 H1N1 occur between April 2009 and April 10, 2010. The intermediate rate in this range is about 61 million people infected with H1N1 2009.
- The CDC estimates that between about 195,000 and 403,000 H1N1-related hospitals occur between April 2009 and April 10, 2010. The intermediate rate in this range is about 274,000 hospitals associated with H1N1 hospitalization.
- The CDC estimates that between about 8,870 and 18,300 H1N1-related deaths occur between April 2009 and April 10, 2010. The intermediate rate in this range is approximately 12,470 deaths associated with H1N1 2009.
It is often stated that about 36,000 die from seasonal flu in the US every year, and this is often understood as an indication that H1N1 strains are not as severe as seasonal influenza. An estimated 36,000 were presented in a 2003 study by CDC scientists published in the Journal of the American Medical Association but only refers to the period 1990-91 to 1998-99. During those years, the estimated number of deaths ranged from 17,000 to 52,000, with an average of about 36,000. The
The 2009 pandemic is causing hospitals across the country to make significant preparations in terms of surging capacity of hospitals, especially in emergency departments and among vulnerable populations. In many cases, hospitals are relatively successful in ensuring that patients most affected by influenza strains can be seen, treated, and disposed of in an efficient manner. The precise case studies of preparation, planning, mitigation, and responsiveness during Fall 2009 are the Children's Hospital of Philadelphia (CHOP). For example, CHOP takes several steps to improve emergency response capacity (ED) capacity through careful planning and mitigation efforts. To improve UL capacity and responsiveness, CHOP uses part of the main lobby area as ED lounge; some hospital-based outpatient facilities at home are being used during the night and weekends for non-emergency cases; The short-term 24-hour ED unit is used to treat DE patients in long-term capacity; non-certified physicians (in pediatric emergency medicine) and in-patient medical nurses used for ED treatment; hospital units usually used for medical or other therapeutic purposes are converted into ED patient rooms; and the room normally used for only one patient is expanded at least to capacity 2
Comparison with pandemics and other epidemics
The annual influenza epidemic is estimated to affect 5-15% of the global population. Although the majority of cases are mild, the epidemic still causes severe illness in 3-5 million people and 250,000-500,000 deaths worldwide. An average of 41,400 people die from influenza-related illnesses annually in the United States, based on data collected between 1979 and 2001. In industrialized countries, severe illness and death occur mainly in high-risk populations of infants, elderly and chronically ill. patients, although the H1N1 flu epidemic (such as the Spanish flu 1918) differed in its tendency to affect younger and healthier people.
In addition to this annual epidemic, Influenza A virus strains caused three global pandemics during the 20th century: Spanish flu in 1918, Asian flu in 1957, and Hong Kong flu in 1968-1969. The strain of this virus has undergone major genetic changes in which the population has no significant immunity. A recent genetic analysis has revealed that three quarters, or six of the eight genetic segments, of the 2009 flu pandemic strain emerge from the North American swine flu strain that circulated since 1998, when new strains were first identified on a farm in North Carolina, and which is the first triple hybrid flu virus ever reported.
The 1918 flu epidemic began with a wave of mild cases in the spring, followed by more deadly waves in the fall, eventually killing hundreds of thousands in the United States and 50-100 million worldwide. Most of the deaths in the 1918 flu pandemic were the result of secondary bacterial pneumonia. Influenza viruses damage the lining of the bronchial tubes and the victim's lungs, allowing common bacteria from the nose and throat to infect their lungs. The next pandemic has fewer casualties due to the development of antibiotic drugs that can treat pneumonia.
Influenza viruses have also caused several pandemic threats during the last century, including the 1947 pseudo-pandemic (considered a mild because although globally distributed, it causes relatively few deaths), 1976 swine flu outbreak and the 1977 Russian flu, all caused by H1N1 subtypes. The world has been on an increasing alert level since the SARS epidemic in Southeast Asia (caused by the SARS virus). Preparedness rates are increasing and sustained with the outbreak of H5N1 avian influenza due to high H5N1 death rates, although current strains have limited human-to-human (anthroponotic) transmission capability, or epidemicity.
People who contract flu before 1957 appear to have immunity to the H1N1 flu. Daniel Jernigan, head of flu epidemiology for the US CDC, has stated: "Tests on blood serum from parents show that they have antibodies that attack new viruses... That does not mean that everyone over 52 is immune, because Americans and The older Mexicans have died of the new flu ".
In June 2012, a published model-based study found that the number of deaths associated with H1N1 influenza may be fifteen times higher than laboratory-confirmed deaths reported. According to their findings, 80% of respiratory and cardiovascular deaths occur in people younger than 65 years and 51% occur in Southeast Asia and Africa. The investigators believe that a disproportionate number of pandemic deaths may occur in this region and that their research suggests that efforts to prevent future influenza pandemic need to effectively target this area.
A WHO study supported in 2013 estimated that 2009 global pandemic respiratory death was ~ 10-fold higher than the WHO laboratory confirmed mortality rate (18,631). Although pandemic mortality estimates are as large as seasonal influenza, sharp changes leading to death among people & lt; 65 y of age occurs, resulting in more years of lost life. Between 123,000 and 203,000 pandemic respiratory deaths were estimated globally over the last 9 months of 2009. Most (62% -85%) were associated with people under age 65. The burden varies greatly among countries. There is almost 20 times higher mortality rates in some countries in America than in Europe. This model connects 148,000-249,000 respiratory deaths to influenza in the average pre-pandemic season, with only 19% in people & lt; 65 y.
See also
- 2009 flu deaths by region
- Health crisis
- Public health emergency (United States)
References
Further reading
External links
- Influenza: H1N1 in Curlie (based on DMOZ)
- Pandemic (H1N1) 2009 at World Health Organization (WHO)
- The International Society for Communicable Diseases PROMED-mail news update
- H1N1 Flu Resource Center in The Lancet
- Novel H1N1 Influenza (Swine Flu) An overview of CIDRAP
- Influenza Research Database - Database of influenza genome sequences and related information.
- CDC 2009 H1N1 Supply Status for Influenza Vaccine
- H1N1 Pandemic and Global Health Security, Dean Julio Frenk, 2009-09-17
- What does Tamiflu saga tell us about drug trials and the big pharmaceutical Guardian, 2014
Europe
- Health-EU Portal The EU Response to influenza
- 2009 influenza A (H1N1) pandemic. European Center for Disease Prevention and Control (ECDC).
- Summary of the pandemic. European Center for Disease Prevention and Control (ECDC).
- European Commission - Public Health EU Coordination on Pandemic (H1N1) 2009.
- British National Flu Pandemic Service
- Official British government information on swine flu from Directgov
- Humans/Pigs A/H1N1 Origins Influenza and Evolution - Analysis of genetic data for the origin and evolution of swine flu viruses.
North America
- Canadian health flu portal
- Pork Health Port Pan-American Health Organization (PAHO)
- H1N1 Influenza (Flu) portal at the US Centers for Disease Control (CDC)
- Portal of pigs, swine flu, and pandemic of the US Government
- Medical Encyclopedia Medline Plus: Swine Flu
- Swine Flu Outbreak, Influenza Virus Sources - Sequence and related resources (GenBank, NCBI)
Source of the article : Wikipedia
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