Encuesta serológica nacional del sarampión en niños: Evidencias para su eliminación

Abstract

Objective. To analyze the frequency and distribution of protective antibodies against measles in a sample of children from 1-9 years old representative of each of the 32 states in Mexico; to contribute to the evaluation of the measles vaccination programs. Material and Methods. Measles antibodies (plaque reduction neutralization (PRN) assay) were studied in 6 270 sera selected from the 24 232 sera from children 1-9 years of age, collected by the 2000 National Health Survey (ENSA 2000) that was conducted from November 1999 to June 2000. Results. Proportion of seropositive samples (>120 IU/L) among 1-4 year-old children (98.3% [95%CI: 97.7-98.8]) was less than that of 5-9 year-old children (99.4% [95%CI: 99.2-99.6]; p<0.001). Seropositivity was associated with the number of measles and/or measles-rubella-mumps vaccine doses and was not associated with gender, place of residence or socio-economic status. Conclusions. The results show that there is adequate vaccination coverage. However, the expansion of data revealed that there are 417 000 children with negative antibody titers who are susceptible to acquiring the disease, transmitting the virus and causing outbreaks.