A post market safety comparison of two vaccination strategies for measles mumps rubella and varicella in Italy.

Friday, 11th of December 2015

A post market safety comparison of two vaccination strategies for measles mumps rubella and varicella in Italy.

Cocchio S Zanoni G Russo F Baldo V; Collaborative group.

http://www.ncbi.nlm.nih.gov/pubmed/26528829

Abstract

It is strategically important to monitor the safety profile of vaccination schedules in order to achieve and maintain high levels of coverage. We analyzed the cohort of individuals actively invited for measles mumps rubella and varicella (MMRV) vaccination in the Veneto region (north-east Italy) from 8/1/2013 to 7/31/2014 assessing the onset of adverse events (AE) relating to two different vaccination strategies for MMRV (MMR+V vs MMRV). During the vaccination session at 14 months old parents were given a form for recording local and systemic reactions to vaccinations for four weeks afterwards. Overall 12288 forms were returned and 84.6% of them were included in this analysis (5130 relating to MMR+V and 5265 to MMRV); 37.3% of the sample reported no AEs with no difference between the two groups. Local reactions were more common in the MMR+V group (9.6% vs 2.9%; RR 3.33; 95% CI 2.79-3.98) while there was no difference in general reactions between the two groups (50% MMR+V vs 52% MMRV). The events most often reported were "fever <39.5°C" which was more frequently associated with the MMRV strategy (p<0.001) and "skin blotches and marks" which occurred more often in the MMR+V group (p<0.001). Reports of "fever ≥39.5°C" were equally distributed between the two groups. Sixteen cases of febrile seizures were reported (0.14% in the MMR+V group and 0.17% in the MMRV group). Similar safety profiles were identified for the two vaccination strategies. Although the method used to record reactions to vaccination demanded considerable resources it enabled important information to be collected on parents perception of the AEs occurring in response to their childs vaccination.