Epidemiology of measles, mumps and rubella in Italy.

A serosurvey for measles, mumps and rubella was conducted in Italy; incidence based on statutory notifications over the last three decades was also calculated. In Italy the diseases followed an endemic-epidemic pattern, with an incidence peak every 2-4 years, and had a limited reduction of incidence attributable to childhood immunization. Lower notification rates were observed in the Southern regions. This is possibly related to greater under notification in the South and is confirmed by our seroprevalence data. Incidence of measles and rubella and proportion of cases among young adults increased significantly in the three decades considered, but not for mumps. Serological data confirmed that these infections are still very frequent in Italy, without significant geographic variation in the country. In the age groups 2-4 and 5-9 years the percentage of individuals still susceptible to each virus was higher than 30%. The proportion of susceptible subjects older than 15 years was similar for the three infections (6.1, 11.7 and 8.8% for measles, mumps and rubella, respectively). The low vaccine coverage for rubella and measles in Italy has so far only partially affected the occurrence of the diseases. No impact of mumps vaccination is visible. The average number of deaths, for each disease, has decreased during the three study periods. Today the priority in Italy is to halt the progressive increase of the mean age of acquisition of the three infections, to eliminate differences in coverage among regions and to conform to European standards. This will be achieved through a combination of increasing MMR vaccine coverage before 2 years of age, implementing vaccination campaigns for low seroprevalence age groups, and/or introducing a second dose of MMR, depending on the level of current MMR coverage.