Surveillance of illness associated with pandemic (H1N1) 2009 virus infection among adults using a global clinical site network approach: the INSIGHT FLU 002 and FLU 003 studies.

The novel pandemic influenza A (H1H1) 2009 virus spread rapidly around the world in 2009. The paucity of prospective international epidemiologic data on predictors of clinical outcomes with pandemic (H1N1) 2009 virus infection stimulated the INSIGHT network, an international network of community and hospital-based investigators, to commence two worldwide clinical observational studies to describe pandemic (H1N1) 2009 virus activity. The purpose of these two studies was to estimate the percent of adult patients with illness due to laboratory-confirmed pandemic (H1N1) 2009 virus infection that experience clinically significant outcomes and to study factors related to these outcomes. Enrollment commenced in October 2009 and will continue until August 2011: as of the end of 2010, 62 sites in 14 countries in Australasia (12 sites), Europe (37) and North America (13) have enrolled 1365 adult patients, with 1049 enrollments into the FLU 002 outpatient study and 316 into the FLU 003 hospitalization study. These 'in progress' INSIGHT influenza observational studies may act as a model for obtaining epidemiological, clinical and laboratory information in future international disease outbreaks.