PERSISTENCE OF VACCINE-INDUCED MEASLES ANTIBODY BEYOND AGE 12 MONTHS: A COMPARISON OF RESPONSE TO ONE AND TWO DOSES OF EDMONSTON-ZAGREB MEASLES VACCINE AMONG HIV-INFECTED AND UNINFECTED CHILDREN IN MALAWI.

Tuesday, 28th of January 2014

[source]Journal of Infectious Diseases[|source]

In Africa, most countries administer a single dose of measles vaccine at age 9 months, complemented by mass vaccination of wider age groups in supplementary immunization activities (SIAs). In 2009, the World Health Organization (WHO) and UNICEF estimated that the regional average coverage with the first dose of measles vaccine was 69%, well below the herd immunity threshold. On the other hand, Africa has the highest prevalence of HIV infection in the world and therefore has the highest risk of HIV-infected infants becoming susceptible to measles earlier in infancy than HIV-uninfected peers.

In this report, the authors observed lower measles antibody prevalence at age 12 months among HIV-infected children compared with HIV-uninfected children immunized using either the 1- or 2-dose MV schedule. The report provides follow-up through at least the second year of life on plaque reduction neutralization assay (PRN) for measles antibody documenting that measles seroprotection persisted through age 24 months among HIV-uninfected children who received 1 or 2 doses of MV. More details are available at: http://jid.oxfordjournals.org/content/204/suppl_1/S149.long

 

Abstract

Background: Previously, we demonstrated that measles antibody prevalence was lower at age 12 months among children infected with human immunodeficiency virus (HIV) than uninfected children following measles vaccination (MV) at ages 6 and 9 months. Among HIV-uninfected children, measles antibody prevalence was lower among 1- than 2-dose MV recipients. Here, we report results through age 24 months.

Methods: Children born to HIV-infected mothers received MV at 6 and 9 months, and children of HIV-uninfected mothers were randomized to MV at 6 and 9 months or MV at 9 months. We followed children through age 24 months. The child s HIV status was determined and measles immunoglobulin G (IgG) level was measured by enzyme immunoassay (EIA) and by plaque reduction neutralization (PRN) on a subset.

Results: Among HIV-uninfected children, the difference in measles antibody prevalence at age 12 months between one- and two-dose recipients reported previously by EIA was shown to be smaller by PRN. By age 24 months, 84% and 87% of HIV-uninfected children receiving 1 or 2 doses, respectively, were seroprotected. Only 41% of 22 HIV-infected children were measles seroprotected at age 20 months.

Discussion: Measles seroprotection persisted through age 24 months among HIV-uninfected children who received 1 or 2 doses of MV. HIV-infected children demonstrated seroprotection through age 12 months, but this was not sustained.