Seroconversion rates and measles antibody titers induced by measles vaccination in Latin American children six to 12 months of age.

A collaborative study was conducted to determine how 2,042 infants responded serologically to measles vaccination in six study areas and to help define the optimal age for measles vaccination in children of Latin America. The results suggest that local factors affect the seroconversion rate and that a success rate of 90% can be attained if initial vaccination is given at nine to 11 months of age, depending on the area. Post-vaccination titers also varied, and higher titers were generally observed in groups with higher seroconversion rates.