Influenza Vaccine Effectiveness against Hospitalisation with Confirmed Influenza in the 2010–11 Seasons: A Test-negative Observational Study

Immunisation programs are designed to reduce serious morbidity and mortality from influenza, but most evidence supporting the effectiveness of this intervention has focused on disease in the community or in primary care settings.  A/Prof Allen Cheng is lead author on a recently published article in PLOS One, in which researchers examined the effectiveness of influenza vaccination against hospitalisation with confirmed influenza. The researchers compared influenza vaccination status in patients hospitalised with PCR-confirmed influenza with patients hospitalised with influenza negative respiratory infections in an Australian sentinel surveillance system.

Overall estimated crude vaccine effectiveness was 57% (41%, 68%). After adjusting for age, chronic comorbidities and pregnancy status, the estimated vaccine effectiveness was 37% (95% CI: 12%, 55%).  In an analysis accounting for a propensity score for vaccination, the estimated vaccine effectiveness was 48.3% (95% CI: 30.0, 61.8%).

Influenza vaccination was moderately protective against hospitalisation with influenza in the 2010 and 2011 seasons.