The authors were interested in whether HIV-infected and HIV-exposed-uninfected (HEU) children may be at increased risk of measles virus infection due to waning immunity following vaccination. They examined the persistence of antibodies to measles vaccination at 4.5 years of age in HIV-unexposed, HEU and HIV-infected children with CD4+ T cells ≥25% who have previously been randomised to immediate antiretroviral therapy (ART) interrupted at 12 months (HIV/Immed-ART-12), 24 months (HIV/Immed-ART-24), or deferred until clinically or immunologically indicated (HIV/Def-ART). The HIV/Def-ART group had ART initiated by a median of 5.8 months of age. Children were followed from 6-12 weeks to 4.5 years. HIV-unexposed (n=95), HEU (n=84), HIV/Immed-ART-12 (n=70), HIV/Immed-ART-24 (n=70) and HIV/Def-ART (n=62) children were scheduled to receive measles vaccination at 9 and 15-18 months of age. Anti-measles serum IgG titres were then quantified at 4.5 years. The authors found that, compared with HIV-unexposed children (2860 mIU/ml), measles antibody geometric mean titres (GMTs) were significantly lower in both HIV/Immed-ART-12 (571 mIU/ml) and HIV/Immed-ART-24 groups (1136 mIU/ml), but similar in the HIV/Def-ART (2777 mIU/ml) and HEU (3242 mIU/ml) groups. Also, when compared with HIV-unexposed children (99%), the rate of antibody titres ≥330 mIU/mL (a presumed sero-correlate for protection) were also significantly lower in the HIV/Immed-ART-12 (70%) and HIV/Immed-ART-24 (83%) groups but similar in the HIV/Def-ART (90%) and HEU (98%) groups. Therefore HIV-infected children in whom ART was interrupted at either 12 or 24 months of age had lower GMTs and lower proportions with seroprotective titres than HIV-unexposed children, which could indicate a potential downside of ART treatment interruption.
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