The effectiveness of national influenza vaccination policies for at-risk populations over 5 seasons in a Scottish general practice

Aim: To determine the effectiveness of serial influenza vaccination.

Scope: Studied in a Scottish GP population, the overall seroresponse rate increased with annual influenza vaccinations and after 5 years it increased from 45.1% to 93.3% for influenza virus A (H1) and from 48.4% to 98.3% for influenza virus A (H3). However, there was little boosting effect with further doses after becoming a seroresponder. The pre-vaccination titres were significantly higher in previous year's seroresponders compared to non-responders.

Conclusions: The policy of annual vaccination is supported by our data in order to increase the disappointing response rate after one dose. However, the lack of a boosting response with subsequent doses and the significant residual immunity after becoming a seroresponder suggests a prior serological immunity check in order to better direct the vaccine supply (in the years of no antigenic drift), to those who need it most. (C) 2008 Elsevier Ltd. All rights reserved.