Abstract
As a result of antigenic drift of the influenza viruses, the composition of the influenza vaccine is updated yearly to match circulating strains. Consequently, there is need to assess the effectiveness of the influenza vaccine (VE). We aimed to measure VE among US military dependents and US-Mexico Border populations during the 2011-12 influenza season. A total of 155 influenza positive cases and 429 influenza negative controls were included in the analysis. Overall adjusted VE against laboratory-confirmed influenza was 46% (95% CI, 19‰ÛÒ64%); unadjusted was 39% (95% CI, 11‰ÛÒ58%). Seasonal vaccination was moderately protective against influenza in this population.