Serologic Survey of Pandemic (H1N1) 2009 Virus, Guangxi Province, China

摘要

To the Editor: Since mid-April 2009, a new in. uenza A virus (H1N1), now called pandemic (H1N1) 2009 virus, has caused in. uenza outbreaks in humans in North America (1) and a worldwide pandemic (2–4). Human pandemics occur when a new virus subtype emerges that is capable of human-to-human transmission in a population with little or no neutraliz-ing antibodies to the new virus (4).The current outbreak presents the fi rst opportunity to directly ob-serve this process. We used hemag-glutination inhibition (HI) and virus neutralization (VN) assays to detect antibodies in 4,043 serum samples from residents (7–84 years of age) of 2 counties in Guangxi Province, Peo-ple's Republic of China, collected dur-ing July–August 2008. These persons were mostly farmers who lived in rural areas. Serum samples were obtained, transported, and frozen at –80°C as described (5). No participants had a history of vaccination against seasonal in. uenza. Antibodies were also detect-ed in another 22 persons (<40 years of age) in Shantou, Guangdong Province, who had received 3 vaccinations for seasonal in. uenza since 2006