Sex-specific differences in serum vitamin A values after measles immunization.

Abstract

To The Editors: Previous studies have shown excess mortality and immune abnormalities among girls immunized with high titer measles vaccine 2 to 4 years after immunization.1, 2 In addition it was reported that there was a difference in seroconversion between boys and girls after immunization with standard titer measles vaccine.3 On the other hand studying the effect of vitamin A supplements on the antibody response to measles vaccine, Benn et al.4 suggested that vitamin A supplements could be beneficial for boys in Guinea-Bissau. In addition in a study from Sudan, girls benefited more from vitamin A supplementation than did boys. To date there have been two studies of association between serum vitamin A concentrations on admission and response to measles vaccination.5-7 In spite of gender differences that are reported in measles vaccination and vitamin A supplementation, there has been no report about serum vitamin A changes after immunization in male and female infants. Recently the effects of live measles and measles-mumpsrubella vaccination on serum vitamin A values were analyzed, and the relation between serum vitamin A concentrations and seroconversion to measles vaccine in 42 healthy well-nourished children was studied at Hacettepe University Ihsan Doğramaci Children's Hospital Well Baby Clinic.6 Analogous to that occurring during natural measles infection,7 our results showed that serum vitamin A concentrations were depressed after measles vaccination, irrespective of whether it was the monovalent or combined measles vaccine. On the other hand the baseline and follow-up mean serum vitamin A values did not differ between seroconverted and nonseroconverted children given measles.6 Similarly Willy et al.7 also reported that serum vitamin A values did not affect the immune response to measles vaccination when children were vaccinated at 9 months of age. In our study 14-to 20-month-old girls had higher serum vitamin A values than did boys on admission (P < 0.05; Table 1, unpublished data). In addition when we analyzed by sex the progressive decline in serum vitamin A concentrations after measles and measles-mumps-rubella vaccines was found to be significant only in female children in both vaccination groups in this limited number of cases and in the absence of children with vitamin A deficiency. To our knowledge it is the first time such a difference has been reported. This decrease in serum retinol could be have serious implications because of the synergistic effects of vitamin A deficiency and measles infection in children with malnutrition and might create sex-specific morbidity and mortality differences.TABLE 1: Serum vitamin A concentrations according to sex In view of the evidence that a decrease in the serum vitamin A concentrations was significant in female children after measles and measles-mumps-rubella vaccines in our study populations, it would seem prudent to proceed on the assumption that serum vitamin A values might play a role in this specific response to the measles vaccine. Further studies are needed to determine the sex-specific difference in the role of serum vitamin A values and measles vaccination especially in infants with malnutrition. S. Songül Yalçin, M.D. Kadriye Yurdakök, M.D. Department of Social Pediatrics; Hacettepe University Institute of Child Health; Ankara, Turkey