FLU NEWS SCAN: Resuming H5N1 research, H7N3 in Mexico, FDA flu strain selections, humidity and flu infectivity

Feb 28, 2013

Dutch researcher resumes H5N1 transmission studies
Dutch flu researcher Ron Fouchier, PhD, has already resumed H5N1 research in his Erasmus University lab, according to a Science News story today. He resumed his work in recent weeks using a European Union grant. He told Science, "I won't be silenced by the Americans anymore." Fouchier led a study on lab-mutated H5N1 viruses that became airborne-transmissible in ferrets. It was one of two such studies that were published last year after being held up over biosafety concerns. During the controversy Fouchier and other leading flu scientists agreed to a research moratorium, which was lifted last month. US officials are currently ironing out details on how to move forward with funding and overseeing such "dual-use" research, which can be used for good or bad purposes. Fouchier said one short-term project that may yield a paper soon is an effort to determine the fewest mutations needed to make H5N1 airborne. He added that Hualan Chen, PhD, and colleagues at the Harbin Veterinary Research Institute in China are also studying mutations that increase H5N1 transmissibility in mammals. Chen confirmed that her group submitted findings to a journal but gave no specifics.
Mar 1 Science News extract
Related Jan 23 CIDRAP News story

H7N3 strikes 11 more Mexican poultry farms
Mexico's agriculture ministry today reported 11 more highly pathogenic H7N3 outbreaks at commercial farms in Guanajuato state, according to a notification from the World Organization for Animal Health (OIE). The events began between Feb 16 and Feb 23 and include five commercial layer farms, one broiler farm, and five breeder farms. Among about 1 million susceptible birds, the virus sickened 62,158 and killed 49,665. Culling operations are under way at the affected farms, according to the report. The same virus recently affected at least nine other farms in Guanajuato, which is located in central Mexico, and affected the neighboring state of Jalisco in 2012, along with isolated events elsewhere.
Feb 28 OIE report

FDA picks flu vaccine strains for 2013-14 flu season
The US Food and Drug Administration (FDA) vaccine advisory group yesterday made its recommendations for strains to include in the next season's flu vaccine. Each February the Vaccines and Related Biological Products Advisory Committee (VRBPAC) meets to review detailed information on circulating strains, US and global flu surveillance, and updates on technical topics such as manufacturing, vaccine response, and the supply of vaccine viruses and reagents. The vote clears the way for companies to start work on making vaccines, which takes several months. The group voted to include the same strains as the ones recently recommended by the World Health Organization (WHO) for the next season's Northern Hemisphere flu season, Morgan Liscinsky, a press officer for the FDA, told CIDRAP News. She said VRBPAC members recommended strains similar to A/California/7/2009 (H1H1) pdm09, A/Victoria/361/2011 (H3N2), and B/Massachusetts/2/2012, which replaces B/Wisconsin/1/2010. They also recommended a virus similar to Brisbane/60/2008 for companies that plan to make quadrivalent vaccines. Votes were unanimous for the trivalent H1N1 and influenza B strain recommendations, with one abstention for the H3N2 and additional B strain recommendation, Liscinsky said.
Feb 21 CIDRAP News story "WHO recommends new B strain for next season's flu vaccine"

Study: Aerosolized flu viruses lose more infectivity at higher humidity
Higher indoor humidity may help temper the infectivity of influenza viruses aerosolized during coughing, according to a study yesterday in PLoS One. National Institute for Occupational Safety and Health (NIOSH) researchers used a computerized bellows-type apparatus to simulate five coughs about 1 minute apart, then collected virus particles using NIOSH bioaerosol samplers. They found that within the first hour of release, 70.6% to 77.3% of flu viruses retained infectivity at relative humidity of 23% or lower. At 43% relative humidity or higher, however, the percentage retaining infectivity dropped to 14.6% to 22.2%. In both conditions most of the loss of infectivity occurred within 15 minutes of aerosol release. The authors conclude, "Maintaining indoor relative humidity >40% will significantly reduce the infectivity of aerosolized virus."
Feb 27 PLoS One study

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