[Variability in the reporting of adverse reactions to the pandemic and seasonal influenza vaccine: seasons 2009-2010 and 2010-2011. Valencian community, Spain].

Background: The loss of confidence in the safety of vaccines derived from alarm conditions, as in the case of the flu pandemic may affect both vaccination coverage and the sensitivity to the reporting of suspected adverse reactions associated vaccines (SRAAV). The aim of the study is to describe the adverse effects reported to the vaccine against pandemic influenza in the 2009-2010 season and against seasonal influenza in 2009-2010 and 2010-2011 seasons, by type of vaccine, risk groups and by age group in the Valencian Community (CV).

Methods: A retrospective descriptive study has been made of the individuals presenting suspected adverse reactions to the influenza vaccine reported through the Vaccine Information System during the seasons 2009-2010 and 2010-2011 in the Valencian Community. 95% confidence intervals were calculated.

Results: During the period 2009-2010 the reporting rate of suspected reactions for seasonal influenza vaccine was 0.020 per thousand doses administered, for the pandemic vaccine 0.95. The reporting rate for seasonal influenza vaccine in the period 2010-2011 was 0.04 per thousand.

Conclusions: There was an increase in the number of reported suspected adverse reactions to the pandemic vaccines compared with the rest of influenza vaccines, during the seasons. The highest suspected adverse reaction reporting rate was for the group of health professionals partner for both vaccines against seasonal and pandemic influenza.