[Evaluation of vaccination programs through serological studies and distributed vaccines].

BACKGROUND

The objective of this study was to compare vaccination coverage in schoolchildren for the measles-mumps-rubella (MMR) and diphtheria-tetanus-pertussis (DTP) triple vaccines, and the poliomyelitis vaccine based on: a) vaccines distributed to vaccination centers; b) reported vaccination history, and c) serological analysis of antibodies.

METHODS

Vaccination coverage was calculated on the basis of vaccination history collected by questionnaire, and by serological analysis of antibodies against measles for the MMR vaccine and against tetanus for the DTP vaccine in a representative sample of schoolchildren in 2001. The vaccination coverage from vaccination registries was obtained by dividing the number of individuals who could have completed their vaccinations by the target population. The concordance between the vaccination history and serological analysis was evaluated using the kappa test.

RESULTS

The vaccination coverage obtained by questionnaire in schoolchildren aged 6-8 and 9-11 years was 85.5 and 87.6% for the DTP vaccine, 89.9 and 89.6% for the MMR vaccine, and 90.4 and 89.4% for the poliomyelitis vaccine, respectively, while the vaccination coverage obtained by serological analysis was 100 and 99.6% for the DTP vaccine and 85.5 and 93.3% for the MMR vaccine, respectively. The vaccination coverages obtained from distributed vaccines were significantly higher: 93.5 and 100% for the DTP vaccine, 96.3 and 98.8% for the MMR vaccine and 100% for the poliomyelitis vaccine. A low concordance was obtained between the vaccination history and serological analysis of antibodies (kappa < 0.2).

CONCLUSION

Planning and evaluation of vaccination programs should be based on vaccination coverages obtained from serological analysis of antibodies in representative samples of schoolchildren.