Self-reported adverse reactions in 4337 healthcare workers immunizations against novel H1N1 influenza

Bias, Harald; Quarcoo, David; Meier-Wronski, Claus; Wicker, Sabine; Seybold, Joachim; Nienhaus, Albert; Groneberg, David A; Roux, Andres de

Unfortunately, the A/H1N1 vaccination coverage was extremely affected by an ongoing public discussion about potential side effects. Therefore, we analysed self reporting questionnaires concerning adverse reactions in 4337 HCWs and medical students. Of course, this study -that was initiated in the acute event of a pandemic and a safety discussion -has a variety of limitations. Apart from the paucity of demographic data, self reporting questionnaires are largely limited since there may be a number of individuals who do not return the questionnaire despite adverse reaction manifestation. However, there was a need to assess potential adverse reactions since the general population and the HCWs asked for data about the new vaccine. Therefore, we decided to undertake a self reporting study despite that fact that the extent of underreporting of side effects can not be examined precisely in the chosen design. It is noteworthy that with our self reporting system we found a rate of 6.7% (291 of 4337 vaccinations). This frequency differs slightly from data from other studies but points to a safe vaccine in terms of acute adverse reactions. A prospective, randomised study with 178 participants by Vajo et al. concluded that all adverse events were rare, mild, and transient. Using the vaccine Fluval P, the most frequent reactions in this study were pain at injection site (eight cases) and fatigue for 1-2 days after vaccination (three cases) [22] . Concerning the vaccination rate we can report a rate of 4337 of about 10 000 employees of the hospital. This is a vaccination rate of over 40%. In a parallel study in Frankfurt/Main, the influenza vaccination rates of the HCWs of the University Hospital Frankfurt were measured. In this study, we were also able to show that the 2009 vaccination rate (seasonal influenza [40.5%], swine flu [36.3%]) was better than the average annual uptake of influenza vaccine in the German health care system (approximately 22% for seasonal and 15% for swine flu) [23] .