Measles immunity gaps among children and adolescents with HIV in zambia despite high measles vaccination and antiretroviral therapy coverage.

OBJECTIVE: The study objective was to identify measles and rubella immunity gaps among people living with HIV (PLHIV) in Zambia despite high measles vaccine coverage and widespread access to antiretroviral therapy.

DESIGN: Nationally representative cross-sectional serosurvey using biorepository specimens.

METHODS: Blood specimens collected in the Zambia Population HIV Impact Assessment survey (ZAMPHIA) of 2016 were tested for measles and rubella IgG antibodies by enzyme immunoassay. Hierarchical generalized additive models were fit to characterize age-specific measles and rubella seroprevalence profiles by HIV infection status. Log-binomial regression was performed to identify factors associated with seronegativity.

RESULTS: Of the 25,383 specimens, a subsample of 11,500 were selected and 9,852 (85%) were successfully tested. Measles seroprevalence was lower among PLHIV compared with HIV-uninfected individuals until approximately 30 years of age. Among children younger than the age of 10 years, measles seroprevalence was 47.2% (95%CI: 32.7%, 61.7%) in PLHIV and 76.4% (95%CI: 74.9%, 78.0%) in HIV-uninfected children in same age category. In contrast, rubella seroprevalence was higher among PLHIV than HIV-uninfected individuals, particularly for children younger than 10 years (68.6% vs. 44.3%, p < 0.001). Having a detectable viral load was associated with being measles seronegative (adjusted PR 0.15, 95%CI: 0.06, 0.38).

CONCLUSIONS: These results from a nationally representative serosurvey demonstrate persistence of measles immunity gaps among PLHIV younger than 30 years of age. There is need to implement the World Health Organization's recommendation to revaccinate children living with HIV against measles following immune reconstitution with antiretroviral therapy to protect these children and prevent measles outbreaks.