1 in 5 people infected with swine flu during first year of epidemic, WHO-led study shows

"At least one in five people worldwide were infected with swine flu during the first year of the 2009-2010 H1N1 pandemic, an international research group said on Friday, but the death rate was just 0.02 percent," Reuters reports (Kelland, 1/25). The WHO-led study "looked at more than 90,000 blood samples before and during the pandemic in countries including India, Australia and the U.K.," and "showed large numbers of people had been infected, although not all would have developed full-blown flu," BBC News notes (Gallagher, 1/25).

"The highest rates of infection were in children, with 47 percent of those aged five to 19 showing signs of having caught the virus," according to a press release from Imperial College London, which adds, "Older people were affected less, with only 11 percent of people aged 65 or older becoming infected" (1/25). "The study, published in the journal Influenza and Other Respiratory Viruses, is based on data from published and unpublished H1N1 seroepidemiological studies, scientists explained," RT notes, adding, "The recent study is said to be crucial for better understanding of the H1N1 virus and preparing efforts to improve prediction of future pandemics" (1/27).