ABSTRACT
OBJETIVO: Analizar la distribución y frecuencia de anticuerpos protectores contra sarampión en una muestra representativa estatal en niños de 1-9 años, así como contribuir a la evaluación de los programas de vacunación contra este agente. MATERIAL Y MÉTODOS: Se estudió la presencia de anticuerpos contra el virus del sarampión en una muestra de la Encuesta Nacional de Salud 2000. Los sueros se recolectaron de noviembre de 1999 a junio de 2000. La muestra consta de 6 270 niños y se utilizó la técnica de reducción de placas por neutralización. RESULTADOS: La seropositividad (>120 UI/L) de los niños de 1-4 años fue menor que la de los niños de 5-9 años, 98.3 por ciento (IC95 por ciento 97.7-98.8) contra 99.4 por ciento (IC95 por ciento 99.2-99.6, p<0.001). Los niveles de seropositividad se incrementaron con el número de dosis de vacuna de sarampión o sarampión-rubeola-parotiditis y no dependen de género, residencia o nivel socioeconómico. CONCLUSIONES: Los resultados muestran que existe una cobertura adecuada en la vacunación; sin embargo, al expandir los datos se observó que existen 417 000 niños que presentaron títulos negativos de anticuerpos, por lo que son susceptibles de adquirir, transmitir el virus y contribuir a la generación de brotes de la enfermedad.
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 percent [95 percentCI: 97.7-98.8]) was less than that of 5-9 year-old children (99.4 percent [95 percentCI: 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.
ABSTRACT
PURPOSE: With the implementation of measles vaccination programs, the number of patients with measles has decreased. However, epidemics still occur with high morbidity in infants less than 1 year of age. This fact calls for the establishment of optimal preventive measures against measles. The study was carried out to determine the effect of measles vaccination on an infant immunized before one year of age, any the measles immunity conferred by MMR. METHODS: Seventy-seven healthy infants (13.7 +/- 1.8 months) were immunized with the MMR vaccine (Triviraten Berna : Edmonston-Zagreb strain, Rubini strain, Wistar RA 27/3 strain), 50 of the infants have received measles vaccine before turning one-year old. The antibody titers of measles-specific IgG were measured by enzyme immunoassay. RESULTS: The antibody titers before and after MMR vaccination were significantly higher in infants previously immunized with measles vaccine compared to those not immunized. However, the greater number of infants not previously immunized with measles vaccine showed significant increase of measles antibody titers after MMR vaccination compared to those previously immunized with measles vaccine. Measles vaccine failure occurred in 6 infants (12.0%), all of whom acquired measles immunity following MMR vaccination. Measles immunogenicity to MMR did not differ with respect to the age of previous measles vaccination. CONCLUSION: The results indicate that measles vaccination in infants less than 1 year of age will not decrease the measles immunity following MMR vaccination, and it is suitable to vaccinate against measles in infants between 6-12 months of age, if needed.
Subject(s)
Humans , Infant , Antibody Formation , Immunization , Immunoenzyme Techniques , Immunoglobulin G , Measles Vaccine , Measles , Measles-Mumps-Rubella Vaccine , VaccinationABSTRACT
PURPOSE: With the implementation of measles vaccination programs, the number of patients with measles has decreased. However, epidemics still occur with high morbidity in infants less than 1 year of age. This fact calls for the establishment of optimal preventive measures against measles. The study was carried out to determine the effect of measles vaccination on an infant immunized before one year of age, any the measles immunity conferred by MMR. METHODS: Seventy-seven healthy infants (13.7 +/- 1.8 months) were immunized with the MMR vaccine (Triviraten Berna : Edmonston-Zagreb strain, Rubini strain, Wistar RA 27/3 strain), 50 of the infants have received measles vaccine before turning one-year old. The antibody titers of measles-specific IgG were measured by enzyme immunoassay. RESULTS: The antibody titers before and after MMR vaccination were significantly higher in infants previously immunized with measles vaccine compared to those not immunized. However, the greater number of infants not previously immunized with measles vaccine showed significant increase of measles antibody titers after MMR vaccination compared to those previously immunized with measles vaccine. Measles vaccine failure occurred in 6 infants (12.0%), all of whom acquired measles immunity following MMR vaccination. Measles immunogenicity to MMR did not differ with respect to the age of previous measles vaccination. CONCLUSION: The results indicate that measles vaccination in infants less than 1 year of age will not decrease the measles immunity following MMR vaccination, and it is suitable to vaccinate against measles in infants between 6-12 months of age, if needed.