Progress towards measles and rubella elimination in Tuscany, Italy: the role of population seroepidemiological profile

Background: As a part of the National Plan for Measles and Congenital Rubella Elimination, a catch-up campaign targeting children aged 7-14 years with Measles-Mumps-Rubella (MMR) vaccine was conducted during 2004-05 in Tuscany, Central Italy. Methods: To assess the profile of measles and rubella susceptibility, immunoglobulin G antibodies against measles (945 subjects) and rubella (1110 subjects) were detected using two commercial enzyme-linked immunosorbent assay tests in sera from a population aged 1-49 years. Results: Overall immunity towards measles increased in the last years, but the WHO-Euro recommended threshold of susceptibility for elimination was attained only in 2- to 4-year-olds. All fertile women up to 29 years had rates of susceptibility clearly higher than those required by WHO-Euro (5%) to eliminate congenital rubella. Despite the reduction of susceptibility among subjects targeted by the catch-up campaign, continuous efforts to increase immunization coverage are needed to eliminate measles and rubella circulation. Our results are predictive of a high chance of measles and rubella outbreaks because of the accumulation of susceptible individuals. Conclusion: Additional catch-up vaccination strategies targeting the adult population (particularly fertile women) are strongly needed to eliminate the risk of measles and congenital rubella syndrome for future generations.