Tolerability of 2 doses of pandemic influenza vaccine (Focetria®) and of a prior dose of seasonal 2009-2010 influenza vaccination in the Netherlands

In the Netherlands, people indicated for seasonal influenza vaccination are divided in 3 risk groups, i.e. those less than 60 y (y) with comorbidity and those 60 y and over with and without comorbidity. Those risk groups were also eligible for pandemic vaccination during the 2009 influenza A(H1N1) pandemic. We assessed tolerability of seasonal influenza vaccination and 2 doses of pandemic influenza A(H1N1) vaccine, adjuvanted with MF-59, administered 2 and 5 weeks after seasonal 2009-2010 vaccination among adults. Vaccinees were asked to return questionnaires on local and systemic adverse events (AEs) after each of 3 consecutive vaccinations given at the office of their General Practitioner. Sex- and risk group-specific AE-frequencies were calculated. Generalized Linear Mixed Model with seasonal vaccination as reference was used to calculate odds ratios (ORs) for AEs of the 2 pandemic doses. 5553 questionnaires (3251 vaccinees) were returned. Vaccinees reported any local AE after seasonal vaccination and both pandemic doses in 34%, 23%, and 18%, respectively. These percentages were 29%, 25%, and 16% for any systemic AE. Men reported fewer local and systemic AEs then women (p