Administration of 100,000 IU vitamin A at the time of measles immunisation is currently recommended for infants in developing countries. However, the safety and value of giving vitamin A, a potent immune enhancer, with live measles virus vaccines are unknown. We conducted a randomised, double-blind, placebo-controlled clinical trial in Indonesia to evaluate the effect of simultaneous vitamin A supplementation on the immune response to measles immunisation at six months of age. 336 infants received either vitamin A (100,000 IU) or placebo when immunised with standard-titre Schwarz measles vaccine. 82% of infants seroconverted to measles. In a multiple logistic regression model adjusting for maternal antibody titres, vitamin A supplementation was associated with a lower likelihood of seroconversion to measles (odds ratio 0.40, 95% CI 0.19-0.88), and girls were less likely to seroconvert than boys (0.34, 0.15-0.76). Immunisation with standard-titre Schwarz vaccine at six months of age in this study population is characterised by high seroconversion rates. However, simultaneous high-dose vitamin A may interfere with seroconversion to live measles vaccine in infants with maternal antibody.
PIP: In 19 villages in the Bogor District of West Java, Indonesia, between December 1992 and March 1993, pediatricians immunized 336 infants 6 months old with 0.5 ml of the standard-titer Schwarz measles vaccine and administered either 100,000 IU vitamin A (169 infants) or a placebo (167 infants) at the same time. The researchers wanted to determine the effect of vitamin A administration on antibody responses to the measles vaccination. 82% of 306 infants seroconverted to measles. About 33% of the 336 infants had no detectable maternal antibodies to measles, indicating that they were very vulnerable to measles infection. The multiple logistic regression model controlling for maternal antibody titers found that vitamin A administration reduced the likelihood of seroconversion to measles (odds ratio [OR] = 0.4). Females were less likely to seroconvert than males (OR = 0.34). At 1 and 6 months after immunization, infants who were administered vitamin A had a 25% lower geometric mean than those who were administered the placebo (p = 0.05 and 0.09, respectively). They were also less likely than the placebo group to develop a generalized rash (8.7% vs. 15.9%; p 0.05), suggesting that vitamin A may limit replication of vaccine-strain measles vaccine. These results suggest that simultaneous high- dose vitamin A may thwart seroconversion to live measles vaccine in infants with maternal antibodies. More research is needed.