Atti del 52° Congresso Nazionale: Società Italiana di Igiene, Medicina Preventiva e Sanità Pubblica (SItI)

We conducted a matched case-control study in Apulia region (about 397,000 children < 10 years of age), where since 2009 MMRV replaced MMR and monovalent varicella vaccines in toddlers, with a second dose given at 5-6 years and a catch-up dose at 11-12 years of age. Vaccination coverage for varicella progressively increased up to 91.7% for one dose and to 85.9% for two doses of MMRV/monovalent-V vaccine in the birth cohorts 2015 and 2010, respectively. Cases of varicella were obtained from the notifiable diseases surveillance system and the hospital discharge registry. Three controls were randomly selected from the population registration system database and matched to cases on the basis of date of birth and residence. Cases and controls vaccination status was retrieved from the Apulian Immunization Information System. Odds Ratios (ORs) with 95% confidence intervals (95% CIs) were calculated by conditional logistic regression. VE was calculated as (1-OR) x100.