PREVALENCE AND CORRELATES OF PROTECTIVE MEASLES ANTIBODY IN HIV-POSITIVE KENYAN CHILDREN ON HAART

Wednesday, 25th of July 2012

 

·       PREVALENCE AND CORRELATES OF PROTECTIVE MEASLES ANTIBODY IN HIV-POSITIVE KENYAN CHILDREN ON HAART 

L. Newman¹, L. Ben-Youssef¹, A. Gatuguta², A. Njoroge³, M. Merkel¹, Q. Ton¹, D. Wamalwa³, B. Payne¹, C. Farquhar<sup>1

1</sup>University of Washington, Seattle, United States, ²Kenyatta University, Nairobi, Kenya, ³University of Nairobi, Nairobi, Kenya

Also accessible at http://pag.aids2012.org/abstracts.aspx?aid=18697

Background: The HIV epidemic has the potential to exacerbate measles morbidity and mortality, as HIV reduces both initial and sustained responses to measles vaccination. Studies have suggested that highly active antiretroviral treatment (HAART) is unable to restore measles immune responses in HIV-infected children who had been previously vaccinated. To establish guidelines for re-vaccination, it is essential to determine whether there is sustained protection against measles in HIV-infected children on HAART.

Methods: A prospective cohort study based at Kenyatta National Hospital in Nairobi enrolled HIV-infected children on HAART with a CD4%>15. Caregivers were interviewed and blood was obtained from children for measles antibody, CD4%, and complete blood count measures. Measles IgG antibody status was determined using ELISA (Siemans, USA). Correlates of positive antibody responses were determined using independent t-tests and multivariate logistic regression. Equivocal measles antibody results were classified as negative.

Results: All ninety-eight HIV-infected children reported measles vaccination before age 12 months. Mean time on HAART was 3.5 years (range 0.5-12.5), mean age was 6.5 years (range 1.1-11.1), and 48 (49%) were male at enrolment. Forty (41%) of the 98 children had positive measles IgG results, 40 (41%) were negative, and 18 (18%) had equivocal results. Children under age 6 were more likely to have protective measles antibody (OR=2.53, 95%CI 1.05-6.12, p-value=0.039). There was no statistically significant association between CD4% or gender and a positive result, though the median CD4% was higher, and more females than males had protective antibody titers (34% vs. 31%; 60% vs. 45%, respectively). Time on HAART was not associated with antibody results.

Conclusions: Among HIV-infected Kenyan children with immune reconstitution on HAART, only 41% had protective levels of measles antibody at baseline. Continued follow-up for 2 years after these children are re-vaccinated will determine optimal timing and immunization guidelines for HIV-infected children on HAART.