Children who contract HIV at birth may not have enough immunity to ward off measles, mumps, or rubella (MMR) as they get older, even if they have received the MMR vaccine, according to the results of a new retrospective study. The study results were published online June 9 in Clinical Infectious Diseases.
"Individuals infected with HIV at birth who did not have the benefit of combined antiretroviral therapy before they were vaccinated should speak with their physician about whether they need a repeated course of the vaccine," author George K. Siberry, MD, medical officer in the Maternal and Pediatric Infectious Disease Branch of the National Institutes of Health's Eunice Kennedy Shriver National Institute of Child Health and Human Development, said in a National Institutes of Health news release.
Investigators compared 428 children who contracted HIV perinatally with 221 children who were born to HIV-positive mothers but did not contract HIV. The children were part of the Pediatric HIV/AIDS Cohort Study and enrolled from ages 7 to 15 years between 2007 and 2009 at centers throughout the United States and Puerto Rico. This means that some of the study participants were born before 1996, when combined antiretroviral therapy came into widespread use.
Serum samples were collected annually, and the most recent, as of October 2011, was used to test for immunity for mumps and rubella with immunoglobulin G immunoassays, and for measles with a plaque reduction neutralization assay.
In both groups, 87% of the children had received two doses of MMR vaccine, yet only 57% of the children perinatally infected with HIV showed immunity to measles compared with 99% of children who were born to HIV-positive mothers but did not themselves have HIV. Similarly, 65% of children with HIV had immunity to rubella compared with 98% of control participants, and 59% had immunity to mumps compared with 97% of control participantss. All three comparisons were highly significant (P < .001). In both groups, 87% had received two doses of MMR vaccine.
The HIV-positive children with immunity were more likely to have received combined antiretroviral therapy before they received the vaccine and had higher levels of CD4+ cells than the HIV-positive children without immunity.
Low immunity could be a result of an inadequate response to the vaccine or to waning of the vaccine's protective effects over time, say the authors. Because samples were taken many years after vaccination, the authors could not distinguish between those possibilities.
"Older children with perinatal HIV infection may contribute to community risk of outbreaks and may be at higher risk of severe disease if they become infected," the authors write. "Prevention of infant HIV infection, early [combination antiretroviral therapy (cART)] for newly HIV-infected infants followed by the standard schedule for MMR immunization, and repeating MMR vaccine doses given to [perinatal HIV] children before they were receiving sustained cART can prevent these vaccine-preventable infections in this vulnerable population," they suggest, adding that their results support current recommendations from the Centers for Disease Control and Prevention to administer two appropriately spaced doses of MMR vaccine after antiretroviral therapy has been established.
The authors have disclosed no relevant financial relationships.
Clin Infect Dis. Published online July 1, 2015. Abstract
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