RESUMO
BACKGROUND AND OBJECTIVE: To evaluate the immunity level achieved with oral polio vaccine in schoolchildren aged 6-12 years of Catalonia (Spain). SUBJECTS AND METHOD: The prevalence of antibodies against poliovirus 1, 2 and 3 was investigated using the neutralizing technique in a representative (n = 197) sample of schoolchildren aged 6-12 years of Catalonia (Spain) obtained in 2001. RESULTS: The prevalence of antibodies was 94.4% for poliovirus 1; 98.5% for poliovirus 2, y 73.1% for poliovirus 3. 93.4% of serum samples had antibodies against poliovirus 1 and 2; 70.6% against poliovirus 1 and 3, and 69.5% against poliovirus 1, 2 and 3. The prevalence of antibodies was similar in different socio-demographic groups. Schoolchildren who had been vaccinated (5 doses) had a higher level of antibodies against poliovirus 3 than those who had not completed vaccination (4 or less doses): 75.4% vs 50.0% (p < 0.05). The prevalence of antibodies against poliovirus 1 and 2 was similar in schoolchildren completing and not completing vaccination. CONCLUSIONS: Results obtained in this study show that 26.9% of schoolchildren aged 6-12 years do not have an adequate immunity level against poliovirus 3 with the oral polio vaccine, being it necessary to develop an immunization program using the inactivated polio vaccine.
