Immunity to poliomyelitis in The Netherlands

Despite a vaccination coverage rate of 97%, several poliomyelitis outbreaks occurred in the Netherlands during the last three decades, all among sociogeographically clustered, unvaccinated persons. Therefore, to eradicate polio, insight into poliomyelitis immunity is particularly useful. In 1995-1996, the authors conducted a population-based study and determined neutralizing antibodies against poliovirus types 1, 2, and 3 in 9,274 sera from the general population and from religious groups rejecting vaccination. In the general population, the antibody prevalence (>/=1:8) was 96.6% (95% confidence interval (CI): 95.9, 97.2), 93.4% (95% CI: 92.3, 94.5), and 89.7% (95% CI: 88.3, 91.0) for poliovirus types 1, 2, and 3, respectively. Antibodies persisted for long periods in persons with natural immunity as well as in persons whose immunity was induced by inactivated polio vaccine. In Orthodox Reformed persons, the antibody prevalence of poliovirus types 1, 2, and 3 was 65.0% (95% CI: 57.2, 72.9), 59.0% (95% CI: 40.1, 77.9), and 68.7% (95% CI: 65.2, 72.2), respectively. The recent outbreaks clearly affected the seroprevalence profiles of Orthodox Reformed groups but not the general population. At present, there is an insufficient social and political basis for mandatory vaccination; therefore, global eradication of poliovirus seems to be the only way to protect these Orthodox Reformed persons against future poliomyelitis outbreaks.