Age for measles immunization seroconversion after measles vaccination at 6-8 months of age - A randomised controlled trial

The, objective of the study was to compare the effectiveness of measles vaccine by seroconversion in vaccinated children with non-vaccinated children of 6 to 8 months age group in a city slam community so as to study the feasibility of advancing the age of immunization. Live attenuated lyophilized Schwartz strain of measles vaccine was used. Hemagglutination inhibition (HI) antibody was estimated. Seroconversion was defined as either the conversion of negative to positive or a two fold rise in titre. One hundred and thirty two children completed the study. There was no difference in the age, sex and nutritional status between vaccinated and non-vaccinated groups (p>0.7). The seroconversion rate in the vaccinated group was 65% and in the non-vaccinated group was 26%. The age, sex and nutritional status did not significantly affect the seroconversion. Oar data suggest that immunization with measles vaccine may be effective as early as 6 months of age. Immunization at 6 months may be needed at least for children in densely populated areas like cities and towns

Prevalence of placentally transmitted antibodies for measles in infants 3 to 11 months old in an urban slum community

Upto 35% of infants aged between 6 and 11 months are infected with measles in India with its associated high morbidity and mortality. The objective of the study is to know the waning pattern of placentally transmitted antibodies (PTA) for measles so that the age at which children are likely to become susceptible to measles infection could be identified. A cross-sectional serological survey of children aged 3 to 11 months in one of the Integrated Child Development Service (ICDS) area in Madras city slums was done. Venous blood from 376 children was collected and was tested for Hemagglutination Inhibition (HI) antibodies by standard microtitration technique. Titre > 1:8 has been considered as protective. The proportion of children with immune level and the Geometric Mean Titre (GMT), declined to the least by 5 months which denotes that most of the infants become susceptible to measles infection from as early as 5 months of age. There is no significant difference in the waning pattern between different age groups, sex and nutritional status. A community study for effectiveness of measles vaccine at 6-8 months of age is needed to know the feasibility of immunization earlier than 9 months of age