RESUMEN
An outbreak of measles due to secondary vaccine failure prompted this investigation into the prevalence of measles antibody in children. We studied 608 children in 7 different age groups: 6, 9, 14 and 18 months and 6, 10 and 15 years. Children in the 2 youngest groups received no vaccination; the rest were vaccinated at 9 months and 15 months. The 15-year-old age group received an additional vaccination. Transplacental measles antibody [Ab] decreased from 10.0% at 6 months to 0% at 9 months. Measles Ab was positive in 52.9% [14 months], 89.4% [18 months], 60.8% 96 years], 45.0% [10 years] and 96.8% [15 years].To increase Ab levels, a booster vaccination is recommended, administered either with the second DPT booster or at pre-high school age