H3N2 JAPAN - World Wide

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FLU CASES HIT 1.7 MILLION AMID H3N2 VIRUS OUTBREAK IN JAPAN

NAM NEWS NETWORK Feb 5th, 2012 .

TOKYO, Feb. 5 (NNN-Xinhua) — Influenza cases expanded by 620,000 to hit an estimated 1.73 million in the past week beginning Jan. 29, a major Japanese newspaper reported on Sunday, citing the National Institute of Infectious Diseases.

Patient numbers roared in all 47 prefectures as the nation experienced its first outbreak of H3N2, a subtype of the influenza A virus, in five years, The Japan Times reported.

About 90 percent of the patients were diagnosed with the strain, the paper said.

It added that some 260,000 babies and infants under 4, who were born after the previous H3N2 outbreak, had been diagnosed with the virus.

According to the institute, flu infections usually peak at this time of the year. — NNN-Xinhua

www.ubalert.com/a/81936

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Influenza A virus subtype H3N2

Influenza A virus subtype H3N2 (also H3N2) is a subtype of viruses that causes influenza (flu). H3N2 Viruses can infect birds and mammals. In birds, humans, and pigs, the virus has mutated into many strains. H3N2 is increasingly abundant in seasonal influenza, which kills an estimated 36,000 people in the United States each year. In the last half of 2011, a dozen human cases of a new variant of the disease have been found in the U.S.A. This new variant is called H3N2v. It appears to be transmissible among humans.[1]

Classification

H3N2 is a subtype of the viral genus Influenzavirus A, which is an important cause of human influenza. Its name derives from the forms of the two kinds of proteins on the surface of its coat, hemagglutinin (H) and neuraminidase (N). By reassortment, H3N2 exchanges genes for internal proteins with other influenza subtypes.

Seasonal H3N2 flu

Seasonal influenza kills an estimated 36,000 people in the United States each year. Flu vaccines are based on predicting which mutants of H1N1, H3N2, H1N2, and influenza B will proliferate in the next season. Separate vaccines are developed for the northern and southern hemispheres in preparation for their annual epidemics. In the tropics, influenza shows no clear seasonality. In the past ten years, H3N2 has tended to dominate in prevalence over H1N1, H1N2, and influenza B. Measured resistance to the standard antiviral drugs amantadine and rimantadine in H3N2 has increased from 1% in 1994 to 12% in 2003 to 91% in 2005.[2]

Seasonal H3N2 flu is a human flu from H3N2 that is slightly different from one of last year's flu season H3N2 variants. Seasonal influenza viruses flow out of overlapping epidemics in East and Southeast Asia, then trickle around the globe before dying off. Identifying the source of the viruses allows global health officials to better predict which viruses are most likely to cause the most disease over the next year. An analysis of 13,000 samples of influenza A/H3N2 virus that were collected across six continents from 2002 to 2007 by the WHO's Global Influenza Surveillance Network showed that newly emerging strains of H3N2 appeared in East and Southeast Asian countries about 6 to 9 months earlier than anywhere else. The strains generally reached Australia and New Zealand next, followed by North America and Europe. The new variants typically reached South America after an additional 6 to 9 months, the group reported.[

Swine flu

"In swine, 3 influenza A virus subtypes (H1N1, H3N2, and H1N2) are circulating throughout the world. In the United States, the classic H1N1 subtype was exclusively prevalent among swine populations before 1998; however, since late August 1998, H3N2 subtypes have been isolated from pigs. Most H3N2 virus isolates are triple reassortants, containing genes from human (HA, NA, and PB1), swine (NS, NP, and M), and avian (PB2 and PA) lineages. [...] Present vaccination strategies for SIV control and prevention in swine farms typically include the use of 1 of several bivalent SIV vaccines commercially available in the United States. Of the 97 recent H3N2 isolates examined, only 41 isolates had strong serologic cross-reactions with antiserum to 3 commercial SIV vaccines. Since the protective ability of influenza vaccines depends primarily on the closeness of the match between the vaccine virus and the epidemic virus, the presence of nonreactive H3N2 SIV variants suggests that current commercial vaccines might not effectively protect pigs from infection with a majority of H3N2 viruses."[4]

Avian influenza virus H3N2 is endemic in pigs in China and has been detected in pigs in Vietnam, increasing fears of the emergence of new variant strains. Health experts say pigs can carry human influenza viruses, which can combine (i.e. exchange homologous genome sub-units by genetic reassortment) with H5N1, passing genes and mutating into a form which can pass easily among humans. H3N2 evolved from H2N2 by antigenic shift and caused the Hong Kong Flu pandemic of 1968 and 1969 that killed up to 750,000 humans. The dominant strain of annual flu in humans in January 2006 is H3N2. Measured resistance to the standard antiviral drugs amantadine and rimantadine in H3N2 in humans has increased to 91% in 2005. In August 2004, researchers in China found H5N1 in pigs.[5] 11/10/2010 The Centers for Disease Control and Prevention (CDC) has issued the following alert: Influenza A (H3N2) virus infections have been recently detected in people in a number of states across the U.S., including two small localized outbreaks. Sporadic cases of influenza and localized summer outbreaks from seasonal influenza viruses are detected each summer.[6]

FLU SPREAD, by season

Hong Kong Flu (1968–1969)

The influenza viruses that caused Hong Kong flu. (magnified approximately 100,000 times)
The Hong Kong Flu was a category 2 flu pandemic caused by a strain of H3N2 descended from H2N2 by antigenic shift, in which genes from multiple subtypes reassorted to form a new virus. This pandemic of 1968 and 1969 killed an estimated one million people worldwide.[7][8][9] The pandemic infected an estimated 500,000 Hong Kong residents, 15% of the population, with a low death rate.[10] In the United States, approximately 33,800 people died.[11]

Both the H2N2 and H3N2 pandemic flu strains contained genes from avian influenza viruses. The new subtypes arose in pigs coinfected with avian and human viruses and were soon transferred to humans. Swine were considered the original "intermediate host" for influenza, because they supported reassortment of divergent subtypes. However, other hosts appear capable of similar coinfection (e.g., many poultry species), and direct transmission of avian viruses to humans is possible. H1N1 may have been transmitted directly from birds to humans (Belshe 2005).[12]

The Hong Kong flu strain shared internal genes and the neuraminidase with the 1957 Asian Flu (H2N2). Accumulated antibodies to the neuraminidase or internal proteins may have resulted in much fewer casualties than most pandemics. However, cross-immunity within and between subtypes of influenza is poorly understood.

The Hong Kong flu was the first known outbreak of the H3N2 strain, though there is serologic evidence of H3N? infections in the late 19th century. The first record of the outbreak in Hong Kong appeared on 13 July 1968 in an area with a density of about 500 people per acre in an urban setting. The outbreak reached maximum intensity in 2 weeks, lasting 6 weeks in total. The virus was isolated in Queen Mary Hospital. Flu symptoms lasted 4 to 5 days.[10]

By July 1968, extensive outbreaks were reported in Vietnam and Singapore. By September 1968, it reached India, Philippines, northern Australia and Europe. That same month, the virus entered California from returning Vietnam War troops. It would reach Japan, Africa and South America by 1969.[10]

"Three strains of Hong Kong influenza virus isolated from humans were compared with a strain isolated from a calf for their ability to cause disease in calves. One of the human strains. A/Aichi/2/68, was detected for five days in a calf, but all three failed to cause signs of disease. Strain A/cal/Duschanbe/55/71 could be detected for seven days and caused an influenza-like illness in calves."[13]

Fujian flu (2003–2004)

Fujian flu refers to flu caused by either a Fujian human flu strain of the H3N2 subtype of the Influenza A virus or a Fujian bird flu strain of the H5N1 subtype of the Influenza A virus. These strains are named after Fujian, a coastal province of the People's Republic of China that is across the Taiwan strait from Taiwan.[14]

A/Fujian (H3N2) human flu (from A/Fujian/411/2002(H3N2) -like flu virus strains) caused an unusually severe 2003–2004 flu season. This was due to a reassortment event that caused a minor clade to provide a haemagglutinin gene that later became part of the dominant strain in the 2002–2003 flu season. A/Fujian (H3N2) was made part of the trivalent influenza vaccine for the 2004–2005 flu season and its descendants are still the most common human H3N2 strain.

2004–2005 flu season

The 2004–05 trivalent influenza vaccine for the United States contained A/New Caledonia/20/99-like (H1N1), A/Fujian/411/2002-like (H3N2), and B/Shanghai/361/2002-like viruses.[15]

2005–2006 flu season

The vaccines produced for the 2005–2006 season use:
an A/New Caledonia/20/1999-like(H1N1);
an A/California/7/2004-like(H3N2) (or the antigenically equivalent strain A/New York/55/2004);
a B/Jiangsu/10/2003-like viruses.

2006–2007 flu season

The 2006–2007 influenza vaccine composition recommended by the World Health Organization on 15 February 2006 and the U.S. FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) on 17 February 2006 use:
an A/New Caledonia/20/99 (H1N1)-like virus;
an A/Wisconsin/67/2005 (H3N2)-like virus (A/Wisconsin/67/2005 and A/Hiroshima/52/2005 strains);
a B/Malaysia/2506/2004-like virus from B/Malaysia/2506/2004 and B/Ohio/1/2005 strains which are of B/Victoria/2/87 lineage.[16]

2007–2008 flu season

The composition of influenza virus vaccines for use in the 2007–2008 Northern Hemisphere influenza season recommended by the World Health Organization on 14 February 2007[17] was:
an A/Solomon Islands/3/2006 (H1N1)-like virus;
an A/Wisconsin/67/2005 (H3N2)-like virus (A/Wisconsin/67/2005 (H3N2) and A/Hiroshima/52/2005 were used at the time);
a B/Malaysia/2506/2004-like virus[18][19]

"A/H3N2 has become the predominant flu subtype in the United States, and the record over the past 25 years shows that seasons dominated by H3N2 tend to be worse than those dominated by type A/H1N1 or type B." Many H3N2 viruses making people ill in this 2007–2008 flu season differ from the strains in the vaccine and may not be well covered by the vaccine strains. "The CDC has analyzed 250 viruses this season to determine how well they match up with the vaccine, the report says. Of 65 H3N2 isolates, 53 (81%) were characterized as A/Brisbane/10/2007-like, a variant that has evolved [notably] from the H3N2 strain in the vaccine—A/Wisconsin/67/2005."[20]

2008-2009 flu season

The composition of virus vaccines for use in the 2008-2009 Northern Hemisphere influenza season recommended by the World Health Organization on February 14, 2008[21] was:
an A/Brisbane/59/2007 (H1N1)-like virus;
an A/Brisbane/10/2007 (H3N2)-like virus;
a B/Florida/4/2006-like virus (B/Florida/4/2006 and B/Brisbane/3/2007 (a B/Florida/4/2006-like virus) were used at the time).[22][23]

As of May 30, 2009: "CDC has antigenically characterized 1,567 seasonal human influenza viruses [947 influenza A (H1), 162 influenza A (H3) and 458 influenza B viruses] collected by U.S. laboratories since October 1, 2008, and 84 novel influenza A (H1N1) viruses. All 947 influenza seasonal A (H1) viruses are related to the influenza A (H1N1) component of the 2008-09 influenza vaccine (A/Brisbane/59/2007). All 162 influenza A (H3N2) viruses are related to the A (H3N2) vaccine component (A/Brisbane/10/2007). All 84 novel influenza A (H1N1) viruses are related to the A/California/07/2009 (H1N1) reference virus selected by WHO as a potential candidate for novel influenza A (H1N1) vaccine. Influenza B viruses currently circulating can be divided into two distinct lineages represented by the B/Yamagata/16/88 and B/Victoria/02/87 viruses. Sixty-one influenza B viruses tested belong to the B/Yamagata lineage and are related to the vaccine strain (B/Florida/04/2006). The remaining 397 viruses belong to the B/Victoria lineage and are not related to the vaccine strain."[24]

2009-2010 flu season

The vaccines produced for the 2009–2010 season use:
an A/Brisbane/59/2007(H1N1)-like virus;
an A/Brisbane/10/2007 (H3N2)-like virus;
a B/Brisbane 60/2008-like antigens.[25]

There also was also a separate vaccine available for Pandemic H1N1 Influenza using the A/California/7/2009-like Pandemic H1N1 Strain.[26]

2010-2011 flu season

The vaccines produced for the 2010–2011 season use:
an A/California/7/2009-like (Pandemic H1N1)
an A/Perth/16/2009-like (H3N2)-like virus;
a B/Brisbane/60/2008-like antigens.[27]

[edit] 2011-2012 flu season

The vaccines produced for the 2011–2012 season use:
an A/California/07/2009 (H1N1)-like virus,
an A/Victoria/210/2009 (an A/Perth/16/2009-like strain) (H3N2)-like virus,
a B/Brisbane/60/2008-like virus.[28]

Note: 2011-2012 Influenza Vaccine Composition

The viruses used in making seasonal flu vaccines are chosen each year based on information collected over the previous year about which influenza viruses are spreading and what vaccine viruses would offer the best protection against circulating viruses. Viruses gathered by 136 national influenza centers in 106 countries as well as information on disease trends are further analyzed by the five World Health Organization (WHO) Collaborating Centers for Reference and Research on Influenza located in Atlanta, Georgia, USA (Centers for Disease Control and Prevention, CDC); London, United Kingdom (National Institute for Medical Research); Melbourne, Australia (Victoria Infectious Diseases Reference Laboratory); Tokyo, Japan (National Institute for Infectious Diseases); and Beijing, China (National Institute for Viral Disease Control and Prevention). The seasonal flu vaccine is usually a trivalent vaccine (a three component vaccine) with each component selected to protect against one of the three groups of influenza viruses circulating most commonly in humans. The 2009 H1N1 vaccine that was made to protect against the pandemic virus first detected in April, 2009 was a monovalent (one-component) vaccine that only protects against the 2009 H1N1 virus. The three vaccine viruses are chosen to maximize the likelihood that the main circulating viruses during the upcoming flu season will be well covered. WHO recommends specific vaccine viruses for vaccine production, but then each individual country makes their own decision for licensing of vaccines in their country. In the United States, the US Food and Drug Administration (FDA) determines what viruses will be used in US–licensed vaccines. WHO recommended that the Northern Hemisphere’s 2011-2012 seasonal influenza vaccine contain the following three vaccine viruses:
an A/California/7/2009 (H1N1)–like virus,
an A/Perth/16/2009 (H3N2)–like virus, and
a B/Brisbane/60/2008–like virus

These are the same viruses that were selected for the Northern Hemisphere for the 2010-2011 influenza vaccine. This recommended composition of the seasonal vaccine for the Northern Hemisphere, including the United States, is the same composition that was recommended for the Southern Hemisphere’s 2011-2012 influenza vaccines. [29]

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2011-2012 Influenza Season Week 5 ending February 4, 2012

Nationally, a low but increasing number of influenza positive specimens have been reported this season, with influenza A (H3N2) viruses being most common. However, there are regional differences in activity levels and which viruses predominate. Over the past several weeks, the proportion of 2009 H1N1 viruses identified has increased nationally and in several regions, most notably in Regions 6 and 9.

www.cdc.gov/flu/weekly/

www.who.int/influenza/gisrs_laboratory/updates/summaryreport/en/index.html

Influenza virus activity in the world

3 February 2012


Source: Laboratory confirmed data from the Global Influenza Surveillance and Response System (GISRS).

Based on FluNet reporting (as of 31 January 2012, 13:35 UTC), during weeks 2 to 3 (8 – 21 January 2012), National Influenza Centres (NICs) and other national influenza laboratories from 84 countries, areas or territories reported data. The WHO GISRS laboratories tested more than 31292 specimens. 4709 were positive for influenza viruses, of which 3633 (77.2%) were typed as influenza A and 1076 (22.8%) as influenza B. Of the sub-typed influenza A viruses, 668 (22.9%) were influenza A(H1N1)pdm09 and 2250 (77.1%) were influenza A(H3N2). Of the characterized B viruses, 90 (33.5%) belong to the B-Yamagata lineage and 179 (66.5%) to the B-Victoria lineage.

Summary

During weeks 2 and 3 in 2012, laboratory confirmed influenza activity continued to increase in many countries in the northern hemisphere but in general influenza activity remained mild.

Globally influenza A(H3N2) continued to be the predominant virus subtype detected. In general, influenza A(H1N1)pdm09 and B activity was low, except for Mexico with A(H1N1)pdm09 predominating and for some Asian countries with B as main circulating virus type. Both B/Yamagata and B/Victoria lineage viruses co-circulated, the majority of viruses detected belong to the B/Victoria lineage.

In Europe, the Middle East, North Africa and North America, influenza A(H3N2) activity continued to increase in many countries with localized to widespread activity reported. Influenza B virus was detected at low levels with A(H1N1)pdm09 detected sporadically in general.

In Asia, influenza activity of A(H3N2) and B viruses continued to increase in many countries, with B viruses predominating in China and China Hong Kong Special Administrative Region, and A(H3N2) viruses in many other countries. Influenza A(H1N1)pdm09 was detected at low levels.

In the southern hemisphere, influenza activity remained low. Among sporadic detections, the majority are influenza A(H3N2) viruses.

A human case of influenza A(H5N1) virus infection was reported in China. The virus belongs to clade 2.3.4.2, and is expected to be sensitive to NAIs and adamantanes by sequencing. Further analysis of the virus including its antigenic relationship with developed candidate reassortant vaccine viruses is being conducted by the WHO Collaborating Centre for Reference and Research on Influenza at the Chinese Center for Disease Control and Prevention.

Other analyses:
Click here to see real-time FluNet charts
www.who.int/influenza/gisrs_laboratory/flunet/charts/en/index.html

Click here to see real-time FluNet data for any week
apps.who.int/globalatlas/dataQuery/default.asp

Click here to see real-time FluNet data for the most recent reporting week
gamapserver.who.int/gareports/Default.aspx?ReportNo=2

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INFLUENZA ZONES...

Analysis - A TIME'S MEMORY

Influenza update - 17 February 2012 - Update number 153 (WHO, edited)


By Giuseppe Michieli
Feb 17, 12 07:54AM |

[Source: World Health Organization, full page: (LINK). Extracts, edited.]

Influenza update - 17 February 2012 - Update number 153

Summary
•Influenza activity in the temperate regions of the northern hemisphere remains low overall. It has continued to increase in the United States and Canada, though overall activity is low. Some countries of western Europe, North Africa, and northern China appear to have reached peak transmission but activity continues to increase in eastern Europe. The levels of both mild and severe disease have been relatively low compared to previous years in most areas reporting.

•Countries in the tropical zone reported low levels of influenza activity with the exception of a few countries in the Americas and parts of southern Asia.

•The most commonly detected virus type or subtype throughout the northern hemisphere temperate zone has been influenza A(H3N2) with the exception of Mexico, where influenza A(H1N1)pdm09 is the predominant subtype circulating, and China and the surrounding countries which are reporting a predominance of influenza type B.
•Notable differences have been reported in the distribution of viruses in severe cases and between age groups. In Canada, influenza A(H1N1)pdm09 accounted for 27% of all influenza A viruses that have been subtyped in <5 year olds but only 5% of subtyped influenza A viruses in cases over the age of 65 years. In Europe, influenza A(H1N1)pdm09 was disproportionately found in cases admitted to hospital for severe acute respiratory infection compared to outpatient cases of influenza-like illness (13-20% vs. ~1.5% respectively).

•Nearly all influenza A viruses detected were antigenically related to the viruses contained in the current northern hemisphere trivalent vaccine.

•Oseltamivir resistance continues to be observed at very low levels and has not increased notably over levels reported in previous seasons.

Countries in the temperate zone of the northern hemisphere

Although persistent upward trends have been reported across the temperate region, it appears that some countries are reaching their peak, including a few countries of western Europe and all of North Africa. The season looks mild by all indicators.

North America

In Canada, overall influenza activity increased in the third week of January but remained low in some areas of the country. The national consultation rate for influenza-like illness (ILI) in Canada decreased slightly but the proportion of samples testing positive increased to 3.4%. Seven regions reported localized influenza activity and 16 regions reported sporadic influenza activity. Eight outbreaks of influenza were reported, three in hospitals and five in long term care facilities, an increase from previous weeks.

The national consultation rate for ILI and general level of influenza activity is mid to low range compared to this time period in previous years. Eighteen influenza-associated hospitalizations were reported this week (three pediatric and 15 adult). Since the start of the season, 38% of all pediatric influenza hospitalizations have occurred in children under the age of two years, while 45% of all adult hospitalizations have occurred in patients aged >65 years. In that time frame, 79% of laboratory confirmed cases were influenza type A and 21% type B; of the influenza A viruses that were subtyped, 90% have been influenza A(H3N2).

Notably, the distribution of virus types and subtypes has not been uniform across all age groups. Fifty-three percent of all laboratory confirmed influenza A(H1N1)pdm09 cases, and 36% of all laboratory confirmed influenza B cases, have been in patients aged <5 years. Influenza A(H1N1)pdm09 accounted for 33% of all influenza A viruses that have been subtyped in <5 years old but only 3% of subtyped influenza A viruses in cases over the age of 65 years.

All influenza A viruses characterized this season in Canada are antigenically related to the viruses contained in the current northern hemisphere trivalent influenza vaccine; however, only 21 of 35 (60%) influenza B viruses are antigenically related to the vaccine strain contained in the current vaccine. The other 14 influenza B viruses were antigenically related to the reference virus B/Wisconsin/01/2010-like, which belongs to the Yamagata lineage.

All 79 influenza A viruses tested for antiviral resistance were susceptible to oseltamivir and zanamivir.

Nationally in the United States of America of America (USA), ILI consultations were low (1.4%) and remained below the national baseline level (2.4%). The percentage of samples positive for influenza increased to 4.9% but was as high as 14% in one region. ILI activity was reported to be low or minimal in all states. The proportion of deaths due to pneumonia and influenza reported in the 122 cities sentinel surveillance system has reached the epidemic threshold for the first time since the start of the season after being predominantly below the seasonal baseline for several weeks.

Since October 2011, 166 laboratory-confirmed influenza hospitalizations were reported. Among these cases, 120 (72.3%) were influenza A, 38 (22.9%) were influenza B, and 2 (1.2%) were influenza A and B co-infections; 6 (3.6%) had no virus type information. Among the 52 of hospitalized cases with influenza A subtype information, 48 (92.3%) were A(H3N2) and four (7.7%) were A(H1N1)pdm09. The most commonly reported underlying medical conditions among adults hospitalized with influenza infection were chronic lung diseases, asthma and obesity. The most common underlying medical conditions in children hospitalized with influenza infection were neurologic disorders and obesity. More than a third of hospitalized children had no identified underlying medical condition.

In the USA, the circulating virus is almost exclusively influenza A(H3N2), except in 6 States (Arkansas, Louisiana, New Mexico, Oklahoma and Texas) where A(H1N1)pdm09 has been predominant in the past 3 weeks. Ninety-nine percent of influenza A(H3N2) and 97% of A(H1N1)pdm09 viruses characterized were antigenically related to viruses contained in the current seasonal trivalent influenza vaccine. Fourteen of the 28 influenza B viruses tested belong to the Victoria lineage of viruses and were characterized as B/Brisbane/60/2008-like, the influenza B component of the 2011-2012 northern hemisphere influenza vaccine.

All viruses tested since 01 October 2011 have been susceptible to the neuraminidase inhibitor antiviral medications oseltamivir and zanamivir.

In contrast to Canada and the USA, in Mexico the majority of all laboratory confirmed cases of influenza since late December 2011 were influenza A(H1N1)pdm09. Localized outbreaks of A(H1N1)pdm09 have also been detected in parts of the country, mostly in the southern States. The Ministry of Health of Mexico has reported that the situation there is similar to previous influenza seasons and that there is no evidence that the virus has changed in its behavior.

Europe

In Europe, influenza activity appeared to be levelling off in Spain and Italy, suggesting the season may now be peaking in a few countries in the west of Europe.

In eastern Europe, Russia, Romania and Bulgaria have seen a trends of increasing influenza activity over recent weeks, though overall activity was still relatively low.

All-cause mortality in the 20 western European countries that are partners in the European Mortality Monitoring Project remains low compared to previous years at this time of the season.

In the 5th week of 2012, 37% of samples from sentinel outpatient clinics tested positive for influenza viruses in Europe, a continued increase from recent weeks. Of these, 96% were influenza type A and 4% were influenza B; 98% of influenza A specimens subtyped were A(H3N2).

Hospitalizations due to severe acute respiratory infection (SARI) continue to be relatively stable with most cases being in the group aged 0-4 years. Nineteen percent of specimens from hospitalized cases of severe acute respiratory infections (SARI) tested positive for influenza, all type A. The distribution of virus types and subtypes in SARI cases has been reported to be different from that in ILI cases. In 159 SARI cases with subtype information from western Europe, 80% were associated with A(H3N2) infection, 13% with A(H1N1)pdm09 and 7% with type B viruses. From eastern Europe, 150 respiratory specimens were collected from SARI patients, of which 25 were subtyped: 20 (80%) as A(H3N2) and 5 (20%) as A(H1N1)pdm09.

Twelve countries have characterized 103 influenza viruses antigenically. All of the influenza A viruses characterized have been antigenically related to the viruses in the current trivalent vaccine; four of eight type B viruses characterized were of the Victoria lineage included in the vaccine and the other four were of the Yamagata lineage.

None of the 15 A(H1N1)pdm09, 46 A(H3N2) and 7 type B viruses tested for neuraminidase inhibitor susceptibility have been resistant since the start of the season.

Northern Africa and eastern Mediterranean

The northern Africa and eastern Mediterranean regions have begun to report a decreasing trend in numbers of positive influenza specimens though virus detection remained widespread. As in Europe, influenza A(H3N2) was the predominant subtype detected, accounting for nearly all of the viruses that have been subtyped.

Temperate countries of Asia

In northern China, both the percentage of outpatient visits that were due to ILI and the proportion of specimens testing positive for influenza (13%) increased since the last report. In contrast to other reporting regions, influenza type B virus is the predominant type across China. In the first week of 2012, 89% of all viruses subtyped in northern China were influenza type B.

The Republic of Korea and Japan have reported a persistent increase in numbers of influenza positive specimens in recent weeks, predominantly A(H3N2). Influenza is spreading nationally across the Republic of Korea.

Countries in the tropical zone

Tropical countries of the Americas

Circulation of influenza A(H1N1)pdm09 and A(H3N2) has been reported in Costa Rica Colombia, and Ecuador.

Influenza A(H1N1)pdm09 has been the most common virus detected in Colombia and A(H3N2) slightly more common in Costa Rica and Ecuador.

Sub-saharan Africa

In sub-Saharan Africa, only sporadic detections were reported.

Tropical Asia

Overall, the influenza activity in tropical Asia remained low.

Influenza B circulation in India and South China has continued to decrease.

In South China the percentage of hospital visits for ILI has decreased to 3.4%, lower compared to recent weeks and at the same time last year.

Influenza type B detections increased in Lao People's Democratic Republic, Bhutan and Singapore.

Countries in the temperate zone of the southern hemisphere

In temperate countries of the southern hemisphere, influenza activity is at inter-seasonal levels. The previously noted persistent inter-seasonal transmission in Chile, Paraguay and Australia has diminished and virus detections are now sporadic in these countries.

Source of data

The Global Influenza Programme monitors influenza activity worldwide and publishes an update every two weeks.

The updates are based on available epidemiological and virological data sources, including FluNet (reported by the Global Influenza Surveillance and Response System) and influenza reports from WHO Regional Offices and Member States. Completeness can vary among updates due to availability and quality of data available at the time when the update is developed.

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Recent Human Influenza A/H3N2 Virus Evolution Driven by Novel Selection Factors in Addition to Antigenic Drift

Matthew J. Memoli,
Brett W. Jagger,
Vivien G. Dugan,
Li Qi,
Jadon P. Jackson and
Jeffery K. Taubenberger

+ Author Affiliations

Viral Pathogenesis and Evolution Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland

Reprints or correspondence: Dr. Jeffery K. Taubenberger, Viral Pathogenesis and Evolution Section Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 33 North Dr., Rm. 3E19A.2 Bethesda, MD 20892 ([e-mail])


Abstract

BackgroundExamination of the evolutionary dynamics of complete influenza viral genomes reveals that other processes, in conjunction with antigenic drift, play important roles in viral evolution and selection, but there is little biological evidence to support these genomic data. Previous work demonstrated that after the A/Fujian/411/2002-like H3N2 influenza A epidemic during 2003–2004, a preexisting nondominant Fujian-like viral clade gained a small number of changes in genes encoding the viral polymerase complex, along with several changes in the antigenic regions of hemagglutinin, and in a genome-wide selective sweep, it replaced other co-circulating H3N2 clades

MethodsRepresentative strains of these virus clades were evaluated in vitro and in vivo

ResultsThe newly dominant 2004–2005 A/California/7/2004-like H3N2 clade, which featured 2 key amino acid changes in the polymerase PA segment, grew to higher titers in MDCK cells and ferret tissues and caused more-severe disease in ferrets. The polymerase complex of this virus demonstrated enhanced activity in vitro, correlating directly to the enhanced replicative fitness and virulence in vivo

Conclusion These data suggest that influenza strains can be selected in humans through mutations that increase replicative fitness and virulence, in addition to the well-characterized antigenic changes in the surface glycoproteins

jid.oxfordjournals.org/content/200/8/1232.short?rss=1&%3bssource=mfr

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Pressure mounts with different flu virus

Peta Rasdien, The West Australian
July 19, 2012, 7:39 am

The earliest start to the flu season in 10 years and the rise of a strain known to cause more severe illness is putting pressure on WA's already stretched health resources.

Experts have warned it could be a bad flu season this year, with flu notifications rising sharply and continuing to flood in.

Around half of cases diagnosed so far are influenza A/H3N2 which is known to be more deadly and cause worse illness than other strains.

Influenza specialist group chair Alan Hampson said influenza A/H3N2 was responsible for more deaths and hospitalisation than influenza B which represents the other half of notifications and tends to cause milder disease.

"Two viruses we are seeing at the moment haven't been prominent in our population for the last three years, so the population's immunity is probably low against those," Professor Hampson said.

"We do know that when we get H3 outbreaks they are the ones that tend to be the more severe outbreaks and have greater effects, certainly on the older adult population."

Professor Hampson said H3N2 viruses were most commonly associated with "excess mortality, more deaths than you would normally expect in the population".

He said each year 2500 to 3500 people died from influenza, but most of those were not recorded as such because the flu symptoms precipitated heart attacks and strokes.

This year's flu vaccine is the same as last year and provides immunity against the H3N2 virus as well as H1N1 and influenza B.

Paul Armstrong, director Communicable Disease Control Directorate, said there had been a slight change in the H3N2 virus compared to previous years.

"So some of the virus that would be circulating would be slightly different from the one that's in the vaccine but the vaccine will still afford good immunity against it," he said.

While older people had good immunity against the H1N1 pandemic strain (because they were infected with a similar virus in the 1950s) they were vulnerable to the H3N2.

"So now that H1N1 pandemic strain has almost disappeared ... it is more likely that older people will get this H3N2 strain, they won't have that protection against as they did with that pandemic H1N1 strain."

Dr Armstrong said it was difficult to forecast what would happen this flu season.

"It started several weeks earlier this year than any time for the past 10 years and we are just on the upswing at the moment so we just don't know where that peak is going to be and we don't know how severe it is.

"Flu seasons are quite variable, they can last anywhere from two months to four or five months."

Dr Armstrong said there had been an unusually high number of flu notifications over the warmer months of the year, which may have contributed to the early start to the flu season this year.

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Novavax Announces Preclinical Results for Seasonal Influenza Vaccine Program

Monday December 17, 7:30 am ET

ROCKVILLE, Md., Dec. 17, 2007 /PRNewswire-FirstCall/ -- Novavax, Inc. (Nasdaq: NVAX - News) announced today favorable results from preclinical studies of its recombinant trivalent seasonal influenza virus-like particle (VLP) vaccine. The trivalent seasonal influenza vaccine is the second of two influenza vaccine programs that Novavax is developing using its recombinant VLP technology. The Company's pandemic influenza vaccine candidate is currently in Phase I/IIa clinical trials.

In a study using mice, two injections of Novavax's trivalent seasonal flu vaccine without an adjuvant induced strong HAI antibody responses against all 3 influenza subtypes contained in the vaccine including H3N2, H1N1, and B. The study showed that when all three seasonal influenza VLPs were given as a single trivalent vaccine, the immune response to each subtype was comparable to that observed when the VLPs were given in a monovalent formulation. Three different dosages of the trivalent vaccine were given; the anti-hemagglutinin (HI) antibody titer increased with dosage and protective levels of HI antibody titers were observed against each subtype at a dose of 3 µg of hemagglutinin.

This preclinical study will be included in an Investigational New Drug ("IND") submission for the seasonal influenza vaccine currently targeted for the second quarter of 2008, with human trials to follow after clearance by the Food & Drug Administration ("FDA"). A toxicology study for the seasonal influenza vaccine has also been initiated as planned.

"We are pleased that the results from this seasonal influenza vaccine preclinical study are in line with our expectations. We are aggressively moving this program forward to file an IND as planned in the second quarter of 2008. If filed as anticipated, this would be our second vaccine IND within 12 months of our first vaccine IND, which we filed in June 2007 for our Pandemic influenza VLP vaccine," said Dr. Rahul Singhvi, Novavax's President and CEO.

About Novavax

Novavax Inc. is committed to leading the global fight against infectious disease by creating novel, highly potent vaccines that are safer and more effective than current preventive options. Using the company's proprietary virus-like particle (VLP) and Novasome® adjuvant technologies, Novavax is developing vaccines to protect against H5N1 pandemic influenza, seasonal flu and other viral diseases. Novavax's particulate vaccines closely match disease-causing viruses while lacking the genetic material to cause disease, which provides potential for greater immune protection at lower doses than current vaccines. With an exclusive portable manufacturing system that allows for rapid mass-production of vaccines, Novavax is uniquely positioned to meet global public health needs.

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Data show significant Neuraminidase Inhibition Antibody Titers in
VLP vaccine recipients

Rockville, MD – February 08, 2010 –/PRNewswire-FirstCall/-Novavax, Inc. (NASDAQ:

NVAX) announced today new data from a clinical study that began in May of 2009 among healthy adults 18 to 49 years of age with Novavax's trivalent seasonal influenza Virus-like Particle (VLP) vaccine. The vaccine matched the influenza strains recommended for the 2008-2009 influenza season including H1N1/Brisbane/59/2007, H1N1 /Brisbane/59/2007, H3N2 A/Brisbane/10/2007, and
B/Florida/04/2006 strains. The study enrolled 241 subjects, including 221 who were randomized to receive either VLP vaccine at 15 mcg or 60 mcg doses or a placebo and 20 subjects who received a licensed inactivated influenza vaccine (TIV).

Novavax reported safety and hemagglutination inhibition (HAI) antibody titers from this study in a poster presentation at the 47th Annual Meeting of the Infectious Diseases Society of America
(IDSA). In addition to the HAI titers, functional antibody against the Neuraminidase enzyme was measured in the sera of immunized subjects using a neuraminidase inhibition assay (NAI) developed by Novavax scientists. Inhibition of neuraminidase activity may be important in reducing the spread of influenza virus down the respiratory tract and severe influenza disease.

Since neuraminidase mutates less rapidly than hemagglutinin(HA), the antibody against neuraminidase may be more effective in protecting against drifted seasonal strains or new, emerging strains of influenza virus.

In continued evaluation of the May 2009 clinical study, Novavax tested volunteers for NAI against H3N2/Brisbane and B/Florida components of the vaccine before and after immunization.

The results showed that 50 to 73% of the volunteers immunized with the Novavax VLP vaccine had a 4-fold increase in the antibody that blocks neuraminidase activity. In contrast, only 1 of 19
volunteers that received the TIV showed a 4-fold rise for NAI. There was no 4-fold rise in volunteers that received placebo.

“These are very exciting results which not only support continued development of novel VLP vaccines against influenza but also provides a cornerstone to potentially differentiate our vaccine
from the current standard of care,” said Dr. Rahul Singhvi, President and Chief Executive Officer of Novavax. “We will continue to evaluate NAI responses in additional clinical trials particularly in the ongoing study in the elderly and work to optimize the NA activity required in our vaccine to maximize NAI responses. We believe these new data reinforce our long standing thesis that VLP influenza vaccines have the potential to induce broad immunity that could lead to meaningful reduction in the burden of disease,” said Dr. Singhvi.

Dr Singhvi presented these new data today in New York city at the BIO CEO Conference.
Further details can be found on the corporate website at www.novavax.com

About NOVAVAX
Novavax, Inc. is a clinical-stage biotechnology company creating novel vaccines to address a broad range of infectious diseases worldwide, including H1N1, using advanced proprietary
virus-like-particle (VLP) technology. The company produces potent VLP-based recombinant vaccines utilizing new and efficient manufacturing approaches. Novavax is committed to using
its VLP technology to create country-specific vaccine solutions. The company has formed a joint venture with Cadila Pharmaceuticals, named CPL Biologicals, to develop and manufacture vaccines, biological therapeutics and diagnostics in India. Additional information about Novavax is available on the company’s website: www.novavax.com

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CDC Reports Cases 14-17 of H3N2v Infection; Shares Advice for Safe Fair-Going


July 27, 2012 -- The state of Indiana this week reported the first novel influenza virus outbreak associated with a fair this season. Following reports of ill swine and humans during a fair in Indiana from July 8-14, samples were taken from swine and humans. Twelve swine were randomly sampled by Indiana state animal health officials, tested at Indiana and federal animal diagnostic laboratories, and found to be infected with swine influenza A (H3N2) viruses. Four people tested positive for influenza A (H3N2) variant virus.* Genetic testing confirmed that the viruses found in humans and those found in swine are nearly identical, and both have the M gene from the pandemic H1N1 virus. These cases bring the total number of detected infections with the H3N2v virus containing the pandemic M gene in the United States since 2011 to 17.


Type A influenza viruses commonly infect swine, causing outbreaks among swine herds. Most of the type A influenza viruses that infect swine are genetically very different from human (seasonal) influenza viruses, including currently circulating seasonal H3N2 viruses. While swine flu viruses seldom infect humans, such infections can and do occur. In fact, influenza viruses can spread both from swine to humans and from humans to swine.

“Fairs are an important event for exhibitors and their swine, and a great experience for fairgoers,” says CDC Influenza Division Deputy Director Dr. Dan Jernigan, “but they are a venue for contact between people and swine. The detection of H3N2v at a few fairs last year, and its re-emergence at one fair so far this year makes this an issue to watch closely.”

The four cases reported by Indiana occurred in people who were exhibiting swine, or family members of people who were exhibiting swine, and were associated with swine contact. Previously, however, there have been H3N2v infections with no reported swine contact and instances of limited human-to-human transmission. “Of the 17 H3N2v infections detected to date, 11 have been associated with swine contact, and eight of these have been associated with fairs,” says Jernigan. In 6 cases, there has been no reported swine contact.

“There may be something different about the H3N2v virus in its ability to be more easily transmitted to people that warrants closer monitoring,” says Jernigan. There is some speculation that acquisition of the M gene from the pandemic H1N1 virus may make H3N2v viruses more transmissible.

According to the International Association of Fairs and Expositions (IAFE), “more than 3,200 fairs are held in North America each year. They provide industrial exhibits, demonstrations and competition aimed at the advancement of livestock, horticulture and agriculture with special emphasis placed on educational activities such as 4-H, FFA [Future Farmers of America] and similar youth development programs.” Swine are a common presence at such fairs.

“As fair season begins across the United States, CDC would like to let people know about some preventive actions they can take to make their fair experience a safe and healthy one,” says Jernigan.

The National Association of State Public Health Veterinarians has developed the Compendium of Measures to Prevent Disease Associated with Animals in Public Settings, 2011 to provide some preventive actions that are applicable to people raising swine, showing swine at fairs, or attending fairs.

Top

Take Action to Prevent the Spread of Flu Viruses Between People and Pigs**
•Wash your hands frequently with soap and running water before and after exposure to animals.
•Never eat, drink or put things in your mouth in animal areas, and don’t take food or drink into animal areas.
•Young children, pregnant women, people 65 and older and people with weakened immune systems should be extra careful around animals.
•If you have animals – including swine – watch them for signs of illness and call a veterinarian if you suspect they might be sick.
•Avoid close contact with animals that look or act ill, when possible.
•Avoid contact with pigs if you are experiencing flu-like symptoms.

If you must come in contact with pigs while you are sick, or if you must come in contact with pigs known or suspected to be infected, or their environment, you should use appropriate protective measures (for example, wear protective clothing, gloves, masks that cover your mouth and nose, and other personal protective equipment) and practice good respiratory and hand hygiene.

Top

Certain People at Higher Risk

“For influenza, certain people may be at higher risk of getting infected, or may be at higher risk for more severe outcomes,” says Jernigan. Studies conducted by CDC have indicated that children younger than 10 would have little to no immunity against H3N2v, whereas adults may have some cross-protective immunity. Most cases of H3N2v have occurred in children at this time. Other people who are at higher risk for seasonal flu-related complications include people with asthma, diabetes, heart disease or neurological disorders. “Prevention is especially important for these people,” says Jernigan.

Pork Safety

It should be noted that swine influenza has not been shown to be transmissible to people through eating properly handled and prepared pork (pig meat) or other products derived from pigs. For more information about the proper handling and preparation of pork, visit the USDA website fact sheet Fresh Pork from Farm to Table.

If You Get Sick
•If you live in an area where H3N2v or other variant virus infections have been identified recently and develop flu-like illness, contact your health care provider (a doctor, physician’s assistant, nurse practitioner, etc.). Tell them if you have had contact with pigs or with other sick people.
•If you live in an area where no H3N2v has been detected, follow CDC’s regular recommendations for seeking treatment for influenza. (If seeking treatment is recommended and you have had contact with pigs, tell your health care provider about it.)
•Also, whenever you have flu symptoms and are seeing a health care provider, always remember to tell them if you have asthma, diabetes, heart disease, neurological and neurodevelopmental conditions, are pregnant, or are older than 65 or younger than 5 years. These conditions and age factors (and others) put you at high risk of serious complications if you get the flu. Most of the people who have been infected with H3N2v so far have been children.
•Flu symptoms usually include fever and respiratory symptoms, such as cough and runny nose, and possibly other symptoms, such as body aches, nausea, or vomiting or diarrhea.
•Health care providers will determine whether influenza testing and possible treatment are needed.
•There are influenza antiviral drugs that can be used to treat infection with H3N2v viruses as well as seasonal influenza viruses. More information about influenza antiviral drugs is available at Treatment (Antiviral Drugs).

Top

More Information
•Indiana State Department of Health Website.
•More information about H3N2v.
•More information on swine influenza can be found in What People Who Raise Pigs Need To Know About Influenza (Flu).
•Additional information and materials, including educational posters [389 KB, 1 page] that can be displayed around animal exhibits, also are available in Compendium of Measures to Prevent Disease Associated with Animals in Public Settings, 2011.

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ADDITIONAL H3N2v CASES IN OHIO CONFIRMED BY CDC
Ohioans Encouraged to Take Precautions, Prevent Spread of Influenza
COLUMBUS — The Ohio Department of Health (ODH) today announced that additional cases of Influenza A variant H3N2 have been confirmed by the Centers for Disease Control and Prevention (CDC). There are currently 14 humans cases identified in Butler County, linked to swine exposure at the Butler County Fair; and one confirmed human case in Clark County, linked to swine exposure at the Ohio State Fair. Those with confirmed cases of H3N2v are between the ages of 3 and 36 years old, and to date, none of the confirmed cases have resulted in hospitalization.
On Monday, ODH hosted a statewide conference call with all local health departments to provide an update on the situation. Local health departments have been urged to work with agriculture and fair officials to post necessary signage and to speak directly with those working in livestock facilities to ensure necessary care is taken to avoid further transmission of the H3N2v strain.
ODH continues to partner with local health departments and health care providers across the state on any reports of human influenza-like illness. Individuals who have reported close contact with swine and are exhibiting flu-like systems will undergo testing. Samples will be sent to the ODH laboratory for preliminary testing and then to CDC for confirmation. ODH will provide notice of any additional H3N2v human case confirmations.
The Ohio Department of Agriculture (ODA) is actively working with industry partners to assist with public education efforts and to increase the number of hand sanitation stations available at county fairs. ODA will make contact this week with each upcoming fair veterinarian instructing them to post signage for both the exhibitors and for the visiting public, to closely monitor swine health and to take temperatures of any ill swine and notify ODA immediately of the results. ODA will continue to swab and test animals as needed throughout the fair season.
With county fairs running into the first week of October in Ohio, ODA and ODH remind residents and visitors that fair attendance is safe. Those attending the fair should remember:
• Wash your hands frequently with soap and running water before and after exposure to animals.
• Never eat, drink or put things in your mouth in animal areas, and don’t take food or drink into animal areas.
• Young children, pregnant women, people 65 and older and people with weakened immune systems should be extra careful around animals.
• If you have animals – including swine – watch them for signs of illness and call a veterinarian if you suspect they might be sick.
• Avoid close contact with animals that look or act ill, when possible.
• Avoid contact with swine if you are experiencing flu-like symptoms.
-more-
More information is available from ODH at: bit.ly/OhioH3N2vUpdates.
August 6, 2012
For Immediate

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COLUMBUS, Ohio | Sat Aug 4, 2012 4:55am IST

COLUMBUS, Ohio Aug 3 (Reuters) - People flocking to agricultural fairs across the United States were warned on Friday to be cautious around pigs after reports this week of nearly a dozen swine flu cases linked to attendance at fairs where sick pigs were present.

Ten new cases of influenza A (H3N2) variant were reported in Ohio and one in Indiana associated with attendance at agricultural fairs. Another case was reported from Hawaii.

"All of this week's reported cases occurred in people who had direct or indirect contact with swine prior to their illness," the Centers for Disease Control and Prevention in Atlanta said in a statement.

The reports had veterinarians at the Ohio and Indiana state fairs testing the animals for infections. Two hogs tested positive and were sent home from the Ohio State Fair, which ends on Sunday. No swine were found to be infected at the Indiana State Fair, which started on Friday and runs through Aug. 19.

Missouri, Iowa and Illinois state fairs start next week. Minnesota's fair starts later in August.

In Butler County, Ohio, 10 human cases have been confirmed and 10 more people are being tested, said Patricia Burg, director of the county's health department. There have been no hospitalizations so far.

The hogs exhibition remained open Friday at the Ohio State Fair in Columbus, where veterinarians were checking the remaining animals as the fair winds down, said Erica Pitchford, spokeswoman for the Ohio agriculture department.

The focus on people was mainly on exhibitors who spend more time in the area than the general public, she said.

"The chances of the virus infecting anyone walking through the barn is very low," Pitchford said.

Swine influenza A viruses rarely infect humans, but can be spread when people are standing near an infected pig which coughs or sneezes. Humans also can get the virus by touching an infected pig or a surface that has been infected, and then touching their own mouth or nose.

The CDC officially has 29 U.S. reported human cases of influenza A variant H3N2 infections since July 2011. Ohio led with 10 cases, Indiana had 7, Iowa 3, Pennsylvania 3, Maine 2, West Virginia 2, Utah 1 and Hawaii 1.

Nineteen cases were associated with fairs where swine were present. Three people with high risk conditions have been hospitalized, but all have recovered.

Health officials in Indiana said on Friday they had confirmed 11 cases statewide of influenza A variant infections, all linked to swine, some of which were exhibited at local fairs, since July 2012.

"As Hoosiers visit fairs around the state this summer, they should take extra care to practice thorough hand washing and avoid eating when around animals," said Dr. Greg Larkin, Indiana's state health commissioner.

In Wisconsin, the state fair opened Thursday and agriculture officials are monitoring the situation, but have not considered canceling events involving swine, said Brian Bolan, the fair's director of agriculture and youth programs.

Dr. John Schiltz, Iowa's state veterinarian, said on Friday that livestock are examined first on the farm by private veterinarians and then at the fair where a veterinarian is available 24 hours a day to examine animals that show signs of illness.

"People are very conscientious and take the proper precautions to make sure their animals are healthy when they come in," Schiltz said.

Children under 5 and adults over 65, pregnant women, and people with chronic medical conditions such as asthma, diabetes or heart disease, are at high risk for serious complications from influenza and should consider avoiding exposure to pigs and swine barns this summer, the CDC said. (Reporting by Allen Bernard in Columbus, Brendan O'Brien in Milwaukee, Kay Henderson in Des Moines, Kevin Murphy in Kansas City and David Dawson in New York; writing by David Bailey; Editing by Bob Burgdorfer)

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Flu: This Year's Vaccine Is Worse Than We Thought 

This year's flu vaccine is only 23 percent effective against this year's predominant strain, H3N2, according to a new report out today from the Centers for Disease Control and Prevention. In the middle of a bad flu season, it turns out the vaccine doesn't offer much protection against the flu…

26 new flu deaths reported in North Carolina Health officials say there were more than two dozen new deaths last week, bringing the total to 90 for this flu season


ABC News

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H3N2

According to this week’s FluView report from the Centers for Disease Control and Prevention (CDC), flu activity is widespread in most of the country and key indicators used to measure severity are climbing sharply. H3N2 viruses remain the most common. Flu activity has been elevated for nine consecutive weeks. An average season lasts about 13 weeks. However, because this season started relatively early, it could last longer than average.

CONTINUED:
www.infectioncontroltoday.com/news/2015/01/h3n2-viruses-remain-the-most-common-cause-of-flu-in-the-us.aspx

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H3N2 Subtype
Long manufacturing timeline hampers annual flu vaccine strain selection, experts say - 04-Feb-2015 

US government scientists told a House subcommittee on oversight and investigations on Tuesday that the six months production time necessary for flu vaccine manufacturers can create difficulties for health experts selecting the appropriate virus strains early in the year.

www.biopharma-reporter.com/Markets-Regulations/Long-manufacturing-timeline-hampers-annual-flu-vaccine-strain-selection-experts-say

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CDC: Flu Activity Expands; Severity Similar to Past H3N2 Seasons

Commentary
Canada Index Fujian H5N2 Matches Crane In Japan
Recombinomics Commentary
January 23, 2015 20:15

The Canada Food Inspection Agency (CFIA) has released a full set of Fujian clade 2.3.4.4 H5N2 sequences, A/turkey/BC/FAV10/2014, from the index farm for the British Columbia outbreak. The sample was collected December 2, 2014 and the sequences matched H5N8 sequences for five of the gene segments (PB2, PA, H5, MP, NS), while the other three gene segments (PB1, NP, N2) matched North American wild bird sequences.

However, the Eurasian sequences were not most closely related to the H5N8 circulating in Europe, which were closely related to an earlier sequence from northeast Russia, A/wigeon/Sakha/1/2014, as well as a subset of initial sequences from Japan, but instead were linked to a white-naped crane sequence, A/crane/Kagoshima/KU1/2014 , from Japan.The uniqueness of this sequence as well as a poultry sequence, A/chicken/Miyazaki/7/2014, indicated the H5N8 sequences in Europe and Asia represented multiple sub-clades, which extended to North America.

The USDA noted the most closely related sequences to initial isolates in Washington, which included an H5N2 sequence, A/Northern pintail/Washington/40964/2014. The H5 sequence was most closely related to A/bean goose/Korea/H40/2014, while the N2 was most closely related to A/American green-winged teal/California/HKWF609/2007. However, the H5 and N8 sequences from A/turkey/BC/FAV10/2014 were distinct from the pintail, even though collections were 6 days and 15 miles apart.

The differences between the first H5N2 cases in Canada and United States are clear. The Korean H5 sequence most closely related to A/turkey/BC/FAV10/2014 is A/Baikal teal/Korea/H96/2014, while A/bean goose/Korea/H40/2014 is most closely related to A/Northern pintail/Washington/40964/2014. The differences in the N2 are more dramatic. The US sequence is most closely related to A/American green-winged teal/California/HKWF609/2007, which forms a sub-clade with A/Northern shoveler/California/8855/2008 and A/avian/Missouri/466554-4/2006, while the Canadian sequence is most closely related to A/American green-winged teal/Wisconsin/10OS3127/2010, which forms a sub-clade with A/Northern shoveler/California/3769/2012 and A/Bufflehead/California/4935/2012.In addition to sub-clade / lineage differences,

Fujian clade 2.3.4.4 has been reported as three different serotypes in Washington (H5N1, H5N2, H5N8). Both H5N1 and H5N2 are ressortants between H5N8 and North American wild birds gene segments, but these two reassortants also differ in internal genes. Initial remarks from CFIA indicated the H5N2 in Canada had 5 H5N8 gene segments and 3 North American wild bird segments (PB1, NP, N2). H5N1 has 4 North American wild bird segments, but the relationship with internal genes with H5N2 is complex. Both have PB1 but H5N2 has NP, which is not in H5N1. Instead the additional North American segments are PA and NS.

However, more combinations may emerge based on the complexity in Taiwan, which has a major Fujian clade 2.3.4.4 outbreak involving three serotypes (H5N2, H5N3, H5N8). The constellation in H5N2 has bene described in media reports as having 3 H5N8 gene segments (H5, MP, NS) with 5 segments from wild birds in Eurasia (that are distinct from the internal genes in H5N8).

The only common genes in the various serotypes in North America and Taiwan are H5 and MP, which may be driving the reassortment which will likely produce more heterogeneity as more detail is released.

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2014-2015 Flu Season

www.cdc.gov/flu/about/season/index.htm