OBJECTIVE: To identify differences in the level of coverage of and opportunity for vaccination among schoolchildren in three areas in Costa Rica with different characteristics: an urban area (with the highest level of socioeconomic development of the three areas), a rural area (with a medium level of socioeconomic development), and a border area (a rural area in northern Costa Rica, on the border with Nicaragua, with the lowest level of socioeconomic development and the highest proportion of foreign immigrants). METHODOLOGY: Following selection of schools by proportional probability, surveys were used with children chosen at random from the first and second grades of elementary schools in the three areas: urban (961 students), rural (544 students), and border (811 students). The data on the vaccines that had been administered were obtained from the children's vaccination cards. Differences among the three areas were evaluated: (1) in the coverage with BCG; with three doses of diphtheria-tetanus- pertussis vaccine (DTP3); with three doses of oral polio vaccine (OPV3); with the first dose of measles-mumps-rubella vaccine (MMR1); and with the second dose of MMR vaccine (MMR2) and (2) in the "opportunity" for the children having received DTP1 + OPV1 before 3 months of age, DTP3 + OPV3 before 7 months of age, and DTP4 + OPV4 + MMR1 before 24 months of age. RESULTS: Out of all the students who had been selected, 80% of them in the urban area had a vaccination card, 73% did in the rural area, and 72% did in the border area (P < 0.05). The coverage levels for BCG, DTP3, and OPV3 were each over 95% in both the urban area and the rural area; however, the coverage levels were significantly lower (P < 0.05) in the border area: BCG, 83%; OPV3, 88%; and DTP3, 88%. Coverage with MMR1 and MMR2 was similar in the three areas. The percentage of schoolchildren with two or more doses of measles vaccine was 98% in the urban area, 92% in the rural area, and 85% in the border area (P < 0.05). In terms of opportunity, 90% of the children had received DTP1 + OPV1 before 3 months of age in the urban area, 89% had in the rural area, and 80% had in the border area (P < 0.05). The percentage of application of the complete basic schedule (DTP4 + OPV4 + MMR1) before 24 months of age was 93% in the urban area, 95% in the rural area, and 84% in the border area (P < 0.05). CONCLUSIONS: The border area had lower coverage of and opportunity for the basic schedule of vaccines, except for MMR. Follow-up campaigns for measles eradication have increased the coverage of the initial and booster doses in all three areas, but the increase has been greatest in the urban area. A greater effort should be made to identify children with an incomplete schedule of vaccinations, with priority going to areas that have a high proportion of immigrants.
OBJETIVO: Identificar diferencias en el nivel de cobertura y en la oportunidad de la vacunación de escolares residentes en tres tipos de zonas de Costa Rica: urbana, rural y fronteriza (rural de la frontera norte del país). MÉTODOS: Mediante encuesta, previa selección de escuelas por probabilidad proporcional, se reunió al azar a alumnos de primero y segundo grados de enseñanza primaria de tres zonas: urbana (n = 961), rural (n = 544) y fronteriza (n = 811). Los datos de las vacunas aplicadas se obtuvieron del carné (cartilla) de vacunación. Se evaluaron las diferencias en la cobertura con BCG, DPT3, VOP3, SRP1 y SRP2 y en la oportunidad de la administración de DPT1 + VOP1 antes de los 3 meses, de DPT3 + VOP3 antes de los 7 meses y de DPT4 + VOP4 + SRP1 antes de los 24 meses de edad, entre las tres zonas. RESULTADOS: Del total de alumnos seleccionados, 80% presentaron carné de vacunación en la zona urbana, 73% en la rural y 72% en la fronteriza (P <0.05). Las coberturas con BCG, DPT3, VOP3 fueron >95% en las zonas urbana y rural, y se encontraron cifras significativamente menores (P <0,05) en la zona fronteriza: BCG, 83%, VOP3, 88% y DPT3, 88%. La cobertura con SRP1 y SRP2 fue similar en las tres zonas. El porcentaje de escolares con dos o más dosis de sarampión fue: 98% en la zona urbana, 92% en la rural y 85% en la fronteriza (P <0,05). Una proporción de 90% recibió DPT1 y VOP1 antes de los tres meses de edad en la zona urbana, 89% en la rural y 80% en la fronteriza (P <0,05). El porcentaje de aplicación del esquema básico completo (DPT4 + VOP4 + SRP1) antes de los 24 meses fue: 93% en la zona urbana, 95% en la rural y 84% (P <0,05) en la fronteriza. CONCLUSIONES: La zona fronteriza mostró menor cobertura y oportunidad en la aplicación de vacunas del esquema básico, con excepción de SRP. La realización de campañas de seguimiento para la erradicación del sarampión ha elevado las coberturas con la SRP1 y el refuerzo de sarampión en todas las zonas, pero el incremento ha sido mayor en la urbana. Debe hacerse un mayor esfuerzo por identificar a niños con esquemas incompletos, principalmente en zonas de alta migración.