Children with HIV who had antiretroviral therapy (ART) that was interrupted at either age 12 or 24 months have lower measles antibody geometric mean titers and seroprotective titers after measles vaccination, compared with children who were not exposed to HIV, according to study results published in Clinical Infectious Diseases.

In the study, the researchers followed participants from age 6 to 12 weeks through 4.5 years. Participants were scheduled to receive measles vaccination at 9 months and 15 to 18 months of age. The researchers used enzyme-linked immunosorbent assay to quantify anti-measles serum IgG titers at age 4.5 years.

The study included children who were not exposed to HIV (n=95), children exposed to HIV but uninfected (n=84), and children with HIV with CD4 T-cell ≥25%, all of whom were previously randomly assigned to immediate ART that was interrupted at 12 months (n=70), at 24 months (n=70), or when clinically/immunologically indicated (n=62).

The results indicated that measles antibody geometric mean titers were significantly lower in both children with HIV with ART interrupted at 12 months (titers: 571 mIU/mL; 95% CI, 409-796; P <.001) and children with ART interrupted at 24 months (titers: 1136 mIU/mL; 95% CI 791-1633; P <.001) compared with children who had not been exposed to HIV (titers: 2860 mIU/mL; 95% CI, 2373-3446). Children with HIV who had ART interrupted when clinically/immunologically indicated had geometric mean titers for measles antibodies similar to children who had HIV exposure (titers: 2777 mIU/ML; 95% CI, 2008-3841; P =.675 compared with titers: 3242 mIU/ml; 95% CI 2617-4014; P =.525, respectively).

Children who had not been exposed to HIV had antibody titers ≥330 mIU/mL; using this as the presumptive cutoff for seroprotectivity, researchers found significantly lower titers in the groups of children with HIV who had ART interrupted at 12 months and 24 months (titers: 70%; P <.001 and 83%; P <.001, respectively). However, antibody titers were similar with this presumptive cutoff for children who had HIV and ART interrupted when clinically/immunologically indicated, as well as children who had been exposed to HIV but were uninfected (90% and 98%, respectively).

“In order to achieve measles elimination by 2020, as targeted by the WHO [World Health Organization], it is essential for children with HIV to receive timely and complete measles vaccination, in addition to early and continuous ART,” the researchers concluded.

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Reference

Mutsaerts EAML, Nunes MC, van Rijswijk MN, et al. Measles immunity at 4.5 years of age following vaccination at 9 and 15-18 months of age among HIV-infected, HIV-exposed-uninfected, and HIV-unexposed children [published online November 12, 2018]. Clin Infect Dis. doi:10.1093/cid/ciy964