MMR vaccination, measles epidemiology and sero-surveillance in the Republic of Ireland

Abstract Objective—Following the introduction of a national measles and subsequent MMR vaccination programme, to determine the susceptibility of 3–14-year-old children to measles, mumps and rubella and to relate the results to the epidemiology of measles and the need for vaccination policy changes. Design—Cross-sectional sero-survey and trends in measles notifications and mortality. Setting—Paediatric hospital outpatient departments in Dublin. Subjects—Sera were collected from 837 children attending the clinics in 1991 and 1992. Results—The prevalence of antibodies in children aged 3–6, 7–10 and 11–14 years was 84, 83 and 95% for measles; 48, 60 and 65% for mumps; and 78, 63 and 74% for rubella, respectively. The prevalence of mumps antibodies may be underestimated. Ninety-six per cent of girls aged 13–14 years had rubella antibodies. A widespread outbreak of measles occurred in 1993. Over recent years, an increasing proportion of measles notifications were in older children. Conclusion—Given sub-optimal uptake of MMR vaccine, outbreaks of infection in pre-and primary school children are inevitable. In such circumstances, a 2-shot MMR vaccine programme with high uptake is essential to prevent a shift of disease into older age groups.