Safety of XXXX adjuvanted vaccine for pandemic @entity683 : results of the vaccination campaign in an Italian health district.

@entity1 @entity683 @entity1156 @entity385
BACKGROUND: The occurrence of pandemic H1N1 @entity683 in 2009 led health authorities to promptly start massive vaccination campaigns. Due to the need of shortening time for development and approval, the pandemic vaccine was prepared by mock-up strategy, and limited safety data were available upon starting vaccine administration. AIMS: To determine the frequencies and clinical features of adverse events (AEs) observed in a population of subjects of an Italian health district receiving pandemic vaccination. The risk for the development of at least one AE was calculated for @entity1 receiving H1N1 vaccine only or H1N1+seasonal vaccine. METHODS: This prospective observational study was performed on the population of La Spezia Health District scheduled to receive pandemic @entity1156 -adjuvanted H1N1 vaccine. Subjects were enrolled at the time of vaccine administration and followed up at least for 6 months. The study population was stratified in two subgroups defined by administration of H1N1 vaccine only or H1N1+seasonal vaccine. AEs were recorded during the first hour following vaccine administration (early AEs) and through periodic telephonic interviews (delayed AEs). RESULTS: An overall number of 506 subjects receiving pandemic vaccine were enrolled (H1N1 only: 131 subjects; H1N1+seasonal: 375 subjects). 233 AEs occurred throughout the study period. Among them, 211 were resolved, while 22 were ongoing at the last available follow-up. Adjusted incidence rate ratio (IRR) for the development of at least one AE was 1.14 (0.77-1.69) for H1N1 only group vs H1N1+seasonal group. @entity1 with a nervous system AE were more frequent in the H1N1+seasonal group (adjusted IRR: 2.33; 95%CI: 1.04-5.23). Only two cases of @entity385 , both in the H1N1+seasonal vaccine group, occurred in @entity1 with cardiovascular risk factors, were classified as serious AEs. CONCLUSIONS: In the present study, the @entity1156 -adjuvanted H1N1 vaccine was generally well tolerated. AEs were usually transient and mild to moderate in intensity. Our findings support the validity of mock-up strategy for rapid development of a safe vaccine in the emergency of a pandemic @entity683 .
