Vaccination against the 2009 pandemic influenza A (H1N1) among healthcare workers in the major teaching hospital of Sicily (Italy)

The aim of the study was to investigate factors involved in vaccination acceptance among healthcare workers (HCWs) and adverse reactions rates associated with pandemic influenza vaccination. The study was carried out in the major teaching hospital of Sicily from November 2009 to February 2010 on 2267 HCWs. A total of 407 (18%) HCWs were vaccinated against the 2009 pandemic influenza A (H1N1). A logistic regression analysis indicates an increased risk of non-vaccination against pandemic influenza in females (OR=1.6; 95% CI=1.3-2.1) compared to males, in nurses/technicians/administrative workers (OR=1.7; 95% CI=1.3-2.2) compared to doctors/biologists, and in HCWs who were non-vaccinated against seasonal influenza in 2008-2009 (OR=4.9; 95% CI=3.7-6.5) compared to vaccinated HCWs. Overall, 302 (74.2%) out of 407 questionnaires distributed to vaccinated HCWs were returned within the observation period. One hundred fifty-two workers (50.3%) experienced at least one adverse reaction (30.1%, local reactions; 6.6% systemic reactions and 13.6% both of them). The most frequent side effect of vaccination was pain at the injection site (43.4%). Twelve (3.9%) out of 302 HCWs stated they experienced influenza-like illness episodes during the follow-up period. The use of an adjuvanted vaccine against pandemic influenza A (H1N1) appears to be an effective and safe preventive strategy, showing a prevalence of both local and systemic adverse reactions not very different from that seen after vaccination with non-adjuvanted seasonal influenza vaccine. Despite this finding, vaccination coverage among HCWs remains very low, suggesting the need to implement educational campaigns directed to groups with lower coverage rates.