title: Pandemic influenza 2009 on Réunion Island: A mild wave linked to a low reproduction number.
abstract: We studied the epidemic trend following the introduction of the pandemic A(H1N1) 2009 in the subtropical Réunion Island. There, the pandemic wave started from week 30 and lasted until week 38, with an estimated attack rate of 12.85 % for symptomatic infections. The best estimate for the initial reproduction number was Ri = 1.26 [1.08; 1.49]. It results that the herd immunity necessary to stop the epidemic growth is of the same magnitude than the attack rate. Thus, a second wave before the 2010 austral winter seems unlikely, unless a viral mutation.
authors.affiliation: Regional office of the French Institute for Public Health Surveillance;  Regional office of French Institute for Public Health Surveillance (Institut de veille sanitaire, InVS) Saint-Denis, Réunion Island, France;  Environmental Health Department of the French Institute for Public Health Surveillance, Saint-Maurice, France and  Regional Office of the French Institute for Health Surveillance.
authors.forename: Philippe
authors.initials: P
authors.lastname: Renault
authors.forename: Eric
authors.initials: E
authors.lastname: D'Ortenzio
authors.forename: Florence
authors.initials: F
authors.lastname: Kermarec
authors.forename: Laurent
authors.initials: L
authors.lastname: Filleul