Immune responses to measles immunization and the impacts on HIV-infected children.

This prospective cohort study was conducted to determine the seroconversion rate and the pattern of antibody response to measles vaccine administered at age 9 months in HIV infected and non-infected children born to HIV-1 seropositive mothers. Thirty children born to HIV-1 seropositive mothers and 3 born to HIV-1 seronegative mothers were recruited. One single dose of Schwarz strain of measles virus vaccine (Rouvax) was given to every child at 9 months of age. Clinical status and measles antibody levels were evaluated at the time just before vaccination, 2 and 12 weeks post-vaccination. Antibody was measured by an enzyme immunoassay commercial kit (Enzygnost, Dade Behring Manufacturer, Germany). Children were classified into 3 groups, groups 1 and 2 were children with and without HIV infection respectively. Group 3 children were those born to HIV-1 seronegative mothers. Of the 33 enrolled children, 16, 14 and 3 were classified as groups 1, 2 and 3 respectively. Four children, 2 of each, in groups 1 and 3 did not complete the study. Group 3 was excluded due to the small number of children recruited. There was no short term complication and no measles infection noted during the course of study. None of the children had pre-existing antibodies. The median (range) of CD4 count and CD4/CD8 ratio measured at the time of vaccination were statistically different between groups 1 and 2 children. Group 2 children had better antibody response than group 1 in terms of seroconversion rate and median of antibody levels at 12 weeks post-vaccination. Only 7 of 29 children (24.1%) had detectable measles antibodies at 2 weeks post-vaccination. A decrease in antibody was noted in 2 symptomatic HIV infected children as their disease had progressed. Various potential predictors of measles vaccine responses in HIV infected children including CD4 count and CD4/CD8 ratio were not statistically different between the responders and non-responders. All 4 asymptomatic HIV infected children were responders. This study demonstrated that all of the children had already lost their maternal acquired antibodies at age 9 months. HIV infected children had a poorerantibody response to measles vaccine than the non-infected children.

Safety and immunogenicity of Bacillus Calmette-Guerin vaccine in children born to HIV-1 infected women.

This prospective cohort study was conducted to determine the complication of Bacillus Calmette-Guerin (BCG) vaccination given to newborn infants born to HIV-1 seropositive mothers and to compare the tuberculin reaction 9 months after BCG vaccination between HIV-1 infected and non infected children. Two hundred and twenty-three infants with BCG immunization at birth were examined. No BCG complication was noted. Tuberculin skin tests were performed on 126 children (56.5%). Eleven of them were excluded because of failure to have skin tests read at 48 hours. Of the 115 infants enrolled to this study, 15 (13%) had no BCG scar and 50 (43.5%) had no tuberculin reaction. Twenty-six children were classified as group 1 or HIV-1 infected children and 89 children were group 2 or HIV-1 non infected. Group 1 children had a smaller tuberculin skin response (X+SD) than group 2 (1.15 +/- 2.82 vs 4.64 +/- 4.29 mm; p < 0.0001). Mean weight + SD of group 1 children was also significantly less than those in group 2 (8,013 +/- 741 vs 8,540 +/- 984 g; p < 0.05). The proportion of children with non reactivity to the tuberculin test, a negative tuberculin test and no BCG scar in group 1 was significantly higher than that in group 2 (76.9% vs 33.7%, 92.3% vs 52.8% and 36.4% vs 6.7% respectively; p < 0.0001 for all). But, the proportion of non reactivity to the tuberculin test in children with or without BCG scar of each group was not different (p > 0.05). Positive tuberculin tests were 7.7% and 47.2% in group 1 and 2 respectively. None of the children with positive tuberculin tests had clinical evidence of tuberculosis. The findings of this study indicate that BCG vaccine given to newborn infants of HIV-1 seropositive mothers is safe. Although tuberculin skin responses of HIV-1 infected children are less than those of HIV-1 non-infected children, it is possible that BCG vaccine might protect these children from developing severe tuberculosis.