Effectiveness of seasonal influenza vaccinations against laboratory-confirmed influenza-associated infections among Singapore military personnel in 2010-2013.

Background: Limited information is available about seasonal influenza vaccine effectiveness (VE) in tropical communities.

Objectives: Virus subtype-specific VE was determined for all military service personnel in the recruit camp and three other non-recruit camp in Singapore's Armed Forces from 1 June 2009 to 30 June 2012.

Methods: Consenting servicemen underwent nasal washes, which were tested with RT-PCR and subtyped.