Lessons from Queens

to determine risk factors for ILI transmission. Because the investigators had the foresight to evaluate these quickly, they were able to assess ILI in household members before the virus was established in the community; thus, incident ILI was probably due to household transmission. Planning for a novel influenza outbreak has been a priority for public health officials since the recognition of H5N1 influenza in Hong Kong in 1997, especially from 2003, when H5N1 outbreaks in birds and infections in people were detected in multiple geographic areas. The 2003 outbreak of severe acute respiratory syndrome taught us that new viruses can spread rapidly across continents. Indeed, the 2009 pandemic H1N1 virus spread globally within 6‐8 weeks. Planning has included strategies to mitigate spread of a new virus; this was particularly crucial in the initial months when a vaccine was not yet available. It is important to determine protective and risk factors for infection in households, because a standard public health recommendation is that ill individuals stay isolated at home to decrease the spread of infection in the community. Evaluating influenza virus transmission