Clinical characteristics of patients with laboratoryconfirmed. The cornerstone of protection remains vaccination, and approved vaccines seek to elicit a hemagglutination inhibition hai titer of. As annual influenza epidemics continue to cause significant morbidity and economic burden, an understanding of viral persistence and transmission is critical for public health officials and health care workers to better protect patients and their family members from infection. The h1n1 virus reappeared in 1977, and is still circulating in humans, while the h3n2 virus was the most common up until 2009 3, 4. During this period, the utah department of health published weekly reports that incorporated data from a variety of sources to describe statewide influenza activity. The authors noted that of 37 influenza b strains with known lineage, 36 were victoria, the type not included in the northern hemispheres trivalent seasonal flu.
It was called swine flu early on because tests showed that it was like flu viruses that occur in swine pigs. Us department of health and human servicescenters for disease control and prevention mmwr august 26, 2016 vol. After the pandemic subsided, sporadic cases of human influenza h1n1 continued to occur worldwide. Based on the taiwan influenza express between july. Antigenic drift of the hemagglutinin ha and neuraminidase na influenza virus proteins contributes to reduced vaccine efficacy.
All but three influenza ah1n1pdm09 viruses tested were sensitive to the neuraminidase inhibitors. Community spread and late season increased incidence of. Influenza viruses are cultured in chick embryo and cell culture mdck. Questions and answers vaccine effectiveness for seasonal influenza vaccines pdf, 102kb.
Influenza h1n1 viruses were analysed for antiviral resistance by pyrose. Novel influenza a h1n1 virus infections in three pregnant women united states, aprilmay 2009. It is recommended that trivalent vaccines for use in the 20162017 influenza season. Influenza a virus h1n1 an overview sciencedirect topics.
Scheifele, md, d taj jadvji, md, f liza lee, msc, g teresa mersereau, bscn, mph, g for the members of the canadian immunization monitoring program active. It is important to bear in mind that the ah1n1pdm09 virus is still circulating in the population. Reassortment of strains of influenza a h1n1 of avian, porcine and human origin. Antigenicity of the 20152016 seasonal h1n1 human influenza. Influenza a 2009 h1n1 remained the predominant strain. Earlier in the season, influenza b victoria lineage viruses were predominant. New evidence emerged following the 2009 h1n1 influenza pandemic that obesity was an independent risk factor for hospitalization, intensive care unit admission and death in laboratory. Complete genome sequence of h1n1 swine influenza virus. Between october 4, 2015 and may 21, 2016, cdc and its partner laboratories detected 18 influenza a h1n1pdm09 viruses 0. Influenza vaccine manufacturing industry perspective for 201617 northern hemisphere influenza vaccine supply, cber, biologics created date 3172016 9. Influenza a virus, influenza b virus, and influenza c virus, respectively table 10.
Components of the 2009 pandemic virus are thought to have derived from the 1918 influenza pandemic. The study indicates that influenza ah1n1pdm09 may mainly be transmitted via the airborne route during air travel. Influenza is an acute viral infection of the respiratory tract that. Information center and center for food security and public health, 2016. Bureau of infectious disease control infectious disease. Stateut wise, yearwise number of cases and deaths from 20162020 new pdf 511 kb. Persistence of influenza a h1n1 virus on stainless steel. Influenza ah1n1pdm09 and postpandemic influenza in lithuania. Pdf molecular characterization of the influenza ah1n1. Surveillance for the 20162017 influenza season officially began on october 2, 2016 and ended on may 20, 2017. National influenza surveillance network data on influenza ah1n1pdm09 virus during the 20092010 to 20152016 seasons. The different viral subtypes that circulated in nh during the 201617 influenza season are presented in table 2. Evolutionary analysis of influenza ah1n1pdm09 during the. Influenza activity united states, 201516 season and composition of the 201617 influenza vaccine.
H1n1 originally referred to as swine flu the h1n1 flu virus caused a worldwide pandemic in 2009. Providing pig industry workers the annual influenza vaccine might reduce transmission risk. On the basis of sequence analysis, aswinekorea612016 is marked from swine h1n1 influenza virus. Annual flu shot will cut childrens risk of illness. A novel pandemic influenza ah1n1pdm09 virus emerged in 2009 globally. In the postpandemic period 20112016, a total of 1078 out of 1911 56% cases were positive for influenza ah1n1pdm09 with cocirculation of different. Ah1n1 predominant, especially among children aged pdf season summary.
Influenza vaccine uptake in 2015 to 2016 in england was lower than last. Molecular characterization of the influenza ah1n1pdm09 isolates collected in the 2015. The influenza h1n1 2009 virus a2009h1n1 was the first pandemic influenza of the 21st century. Flu ve network from november 2, 2015, through april 15, 2016. A standardised approach for the reporting of such inflight outbreak investigations would help to provide more convincing evidence for such inflight transmission events. Immunization practices acip on june 22, 2016pdf icon.
Of the 348 labconfirmed flu cases that turned up in the imove system during the study period, 246 were 2009 h1n1, 77 were influenza b, 21 were h3n2, and 4 were unsubtyped influenza a. It is an orthomyxovirus that contains the glycoproteins haemagglutinin and neuraminidase. It has affected the w hole world and caused more than 18,000 deaths rewar et al. Pigs first became infected with the influenza virus in 1918, and the first swine virus was found in humans in 1974. In 2018, a veterinarian became sick shortly after swabbing sows exhibiting respiratory syndrome on a farm in france.
Who recommended composition of influenza virus vaccines. For this reason, they are described as h1n1, h1n2 etc. The 1918 pandemic, caused by worldwide spread of a human influenza a h1n1 virus, was responsible for 4050 million deaths. Utility of statelevel influenza disease burden and severity estimates to investigate an apparent increase in reported severe cases of influenza ah1n1 pdm09. Davlin sl, blanton l, kniss k, mustaquim d, smith s, kramer n, et al.
However, recent poor vaccine performance raises questions regarding the protection afforded and whether other. Weekly influenza respiratory illness activity report. The first recognized case of human disease from a swine influenza triple reassortant influenza a h1n1 virus occurred in a 17yearold who had been exposed to pigs at a slaughterhouse in. In virology, influenza a virus subtype h1n1 ah1n1 is the subtype of influenza a virus that was the most common cause of human influenza flu in 2009, and is associated with the 1918 flu pandemic. Despite longterm investment, influenza continues to be a significant worldwide problem. Division of public health respiratory virus surveillance report week 14. Recommended composition of influenza virus vaccines for. Two viruses showed reduced inhibition by oseltamivir and peramivir, due to a h275y substitution in the neuraminidase. We report here the genome sequence of the influenza a virus strain aswinekorea612016, isolated from swine in the republic of korea. The first outbreak occurred in 2009 and infected people all over the world. While the h1n1 viruses have continued to circulate since the pandemic, 2014 is the first season since 2009 that h1n1 has been so predominant in the united states.
Ah1n1pdm09 virus strains isolated during the period 20092016 on the. Three genera exist with this family that pertain to influenza viruses, influenzavirus a, influenzavirus b, and influenzavirus c, each of which contain a single species, or type. The 2019 calendar year marked the pandemics 10th anniversary. Epidemiologic data and genetic analyses revealed consecutive humantoswine and swinetohuman influenza ah1n1pdm09 virus transmission, which occurred despite some biosecurity measures. Seasonal influenza h1n1 national centre for disease control. It is now a human seasonal flu virus that also circulates in pigs. Influenza viruses are susceptible to heat, ph extremes, dryness, and are generally. Influenza the center for food security and public health iowa. Surveillance of influenza and other respiratory viruses in the united.
Flu vaccination has been shown to prevent flu illnesses, doctors visits and hospitalizations and can. The infectivity and persistence of two influenza a h1n1 virus strains anew caledonia201999 and abrisbane59. The centers for disease control and prevention cdc continues to. To analyze antigenic drift in human seasonal h1n1 viruses derived from the 2009 pandemic h1n1 virus ph1n1like viruses accounts for the limited effectiveness around 40% of vaccination against ph1n1like viruses during the 20152016 season, nasal washesswabs. The influenza a h1n1pdm09 virus, or swine flu, is a novel strain that circled the globe in 2009 and resulted in approximately 575,400 deaths. Pdf evolution of pandemic influenza virus ah1n1pdm09 in 2009. Everyone 6 months and older needs a flu vaccine each year.
Cdcs endofseason influenza vaccine effectiveness ve. Background influenza, or flu, is a respiratory infection caused by a variety of influenza viruses. Historical perspectiveemergence of influenza a h1n1 viruses, n engl j med 361. Investigating obesity as a risk factor for influenza. Disease outbreak control division influenzarespiratory disease surveillance report morbidity and mortality. Clinical characteristics of patients with laboratory. Behavior of influenza seasons in mexico from 2010 to 2016.
Find information on coronavirus disease 2019 covid19. Utility of statelevel influenza disease burden and. Historical perspective emergence of influenza a h1n1. Influenza activity united states, 201516 season and composition of the 201617. Candidate vaccine viruses and potency testing reagents for development and production of vaccines for use in the northern hemisphere 20152016 influenza season. The 1918 h1n1 influenza pandemic was among the most severe, with influenza attributed mortality. Ending april 4, 2020 influenza vaccine composition 20192020. All influenza a h1n1pdm09 viruses tested were susceptible to zanamivir.
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