Aug 13, 2010
Study: Return to school launched pandemic flu wave
The opening of schools in the fall of 2009 seemed to trigger the United States' second wave of pandemic H1N1 flu, with outpatient visits for flu-like illnesses spiking about 14 days after students returned, researchers from the University of Washington reported yesterday in the Journal of Infectious Diseases. To assess any relationship between return to school and flu activity, they looked at Google Flu Trends by state and national level, regional flu baselines, and public school opening dates across many localities and regions. Between Aug 9 and Sep 24, flu-like activity for all states exceeded baselines, and most of it was pandemic H1N1. Flu did not exceed state baselines before school opening dates, except in Minnesota. The authors concluded that understanding the relationship between school opening dates and pandemic influenza spread might be useful for future pandemic planning and that community mitigation efforts aimed at students before school starts may be a useful strategy to reduce the spread of the virus.
Aug 12 J Infect Dis abstract
Adjuvanted vaccine tests well in elderly
A study from Belgium found that a single dose of adjuvanted pandemic H1N1 vaccine was effective and well tolerated in adults up to age 85 and that previous trivalent seasonal vaccination did not reduce its effectiveness. The researchers administered a monovalent H1N1 vaccine containing 3.75 micrograms of antigen and the oil-in-water adjuvant AS03A to healthy adults in two age-groups, 18 to 60 years and over 60 years. Antibody titers against H1N1 were measured after 1 dose, with half the patients then given another dose. Immune responses meeting European licensure criteria were noted in 97.5% and 87.4% of subjects in the younger and older age-groups, respectively, and these levels persisted whether or not subjects received the second dose. Previous vaccination against seasonal influenza within the preceding two flu seasons was associated with significantly lower mean antibody titers after both dosing schedules in 18- to 60-year-olds.
Early-release Clin Infect Dis abstract
Pigs in Indonesia have asymptomatic H5N1 infections
An international team of researchers reports finding asymptomatic H5N1 avian influenza infections in pigs in Indonesia in 2005, 2006, and 2007, suggesting that the animals offer the virus an opportunity to adapt to mammals. The team sampled pigs in several areas of Indonesia during three rainy seasons: January and February 2005, October 2006 to February 2007, and November 2008 to April 2009, according to their early-release report in Emerging Infectious Diseases (EID). They found H5N1 viruses in 52 of 702 samples (7.4%). All the positive samples were collected in the first two seasons and came from areas where poultry outbreaks of H5N1 had occurred. None of the pigs showed signs of flu-like illness at the time of sample collection. A phylogenetic analysis showed that the viruses had been introduced into pigs in Indonesia on at least three occasions. The researchers also found one isolate that had the ability to recognize human-type virus receptors. "Our data suggest that pigs are at risk for infection during outbreaks of influenza virus A(H5N1) and can serve as intermediate hosts in which the virus can adapt to mammals," they conclude.
Early-release EID report
H5N1 widespread in Jakarta's poultry
Seventy percent of recent poultry feces samples tested in Jakarta were found to contain H5N1 viruses, according to a Jakarta Post report published today. The finding was reported by the head of the city's Agriculture, Maritime, and Animal Husbandry Agency, who said thousands of samples were tested. She said the birds all appeared healthy. The story also said that poultry restrictions enacted by the city to control avian flu have been stalled because of widespread public criticism earlier this year. The law requires certificates for pet bird owners and limits poultry slaughterhouses to six areas on the city's periphery.
Aug 13 Jakarta Post story