Immunity against poliomyelitis in the Netherlands, assessed in 2006 to 2007: The importance of completing a vaccination series

Abstract

Europe has been declared polio-free since 2002. Here we describe the seroprotection against poliomyelitis in the Dutch population using banked serum samples. Samples from 1,581 inhabitants of eight municipalities with low vaccination coverage (LVC) and an additional 6,386 samples from a nationwide (NS) group (clinical trial number: ISRCTN20164309; collected in 2006-07) were tested for neutralising antibodies (log2 reciprocal titres (GMT); non-protection <3) against all three poliomyelitis serotypes. Demographic and epidemiological data were used for statistical regression analysis. Seroprevalence in the NS was 94.6% (type 1), 91.8% (type 2) and 84.0% (type 3). Infants (0-7 months-old) had ≥80% seroprevalence for all serotypes. The highest seroprevalence was found in children, with type 1 and type 2 in five year-olds and type 3 in nine to 10 year-olds. In the LVC group, orthodox protestants, many of whom refuse vaccination, showed seroprevalence rates of 64.9% (type 1), 61.0% (type 2) and 62.1% (type 3). In the NS group, non-Western immigrants and travellers to non-European continents had higher seroprevalences compared to Western immigrants and travellers within Europe, respectively. The Dutch National Immunisation Programme against poliomyelitis has provided good seroprotection, with high and long-lasting GMTs against all serotypes upon completion. The unvaccinated population remains at risk.