FLU NEWS SCAN: Flu virus shedding, pandemic prevention approaches http://t.co/vZayUglY
Study finds substantial flu virus shedding even without symptoms In a German study, 30% of patients' tested positive for flu the day before symptoms developed, and asymptomatic patients had about the same viral loads as sick patients, according to a report yesterday in PLoS One. Investigators conducted a prospective household study using data from 2007 to 2011 in Berlin and Munich. They analyzed data from 122 index patients and 320 household contacts, of whom 67 became secondary flu case-patients. Of the 189 case-patients, 12 had seasonal H1N1 flu, 19 had H3N2, 98 had pandemic 2009 H1N1, and 60 had influenza B. Nine (14%) of 65 unvaccinated secondary case-patients—all adults—were asymptomatic. Viral loads in patients' nasal specimens peaked on day 1, 2, or 3 for all flu strains, then declined steadily till days 7 through 9. On the day before symptom onset, 12 of 40 specimens (30%) were positive. Viral load in six asymptomatic patients was similar to that in those having symptoms. Infectiousness, as measured by viral culture, lasted 4 to 6 days after symptom onset, and viral load did not seem to be influenced by antiviral therapy, age, or vaccination status, the team found. They conclude, "Asymptomatic/subclinical infections occur infrequently, but may be associated with substantial amounts of viral
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