Evaluatie van het Rijksvaccinatieprogramma: immuniteit van de Nederlandse bevolking tegen bof, mazelen en rodehond

To assess the immunity to measles, mumps and rubella in the Dutch population and among orthodox reformed individuals who mostly refuse vaccination.

Design

Cross-sectional study.

Methods

A sample of 40 municipalities was drawn proportional to their size, in 1995/’96. In addition, 8 municipalities with low vaccine coverage were chosen to have access to orthodox reformed individuals. In each municipality an age-stratified sample was drawn of 380 persons (0-79 years). Participants were asked to give a blood sample and to fill out a questionnaire. Sera were tested with an ELISA for antibodies against measles (national sample: n = 8303; orthodox reformed individuals: n = 254), mumps (n = 8298 and n = 254), and rubella (n = 8295 and n = 254).

Results

In the nationwide sample the prevalences of antibodies to measles, mumps and rubella (MMR) were 95.7, 95.2, and 95.6. The seroprevalence was somewhat lower in the vaccinated age groups than in the unvaccinated age groups. For measles, mumps and rubella a decline in prevalence of antibodies of 2.0-5.4 was visible between the ages when MMR vaccination is offered (14 months and 9 years). The overall seroprevalence for mumps, measles and rubella in the orthodox reformed was 2.6 to 4.2 lower than in the national sample; this could be ascribed to a low prevalence in the young orthodox reformed, especially in the 1-4-year-olds (36.2, 38.8 and 54.5).

Conclusion

The immunity in the general Dutch population was amply sufficient to prevent epidemics of mumps and rubella. Regarding measles, the immunity in de vaccinated age groups was theoretically too low (< 95). However, the recent epidemic among orthodox reformed children showed the contrary; there was hardly any spread to the general population.