A large percentage of children with perinatal HIV infections may not have sufficient immunity to ward off measles, mumps, and rubella (MMR), even though they may have been vaccinated against these diseases, according to a new study.
“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,” stated lead author George K. Siberry, MD, Medical Officer in the Maternal and Pediatric Infectious Disease Branch of National Institutes of Health’s Eunice Kennedy Shriver National Institute of Child Health and Human Development.
Effective combined antiretroviral therapy (ART) before immunization is a strong predictor of current seroimmunity, he and his colleagues noted.
The study, which is a collaboration with the CDC, included 428 perinatally exposed and HIV-infected children and 221 perinatally HIV-exposed but uninfected children. The researchers enrolled children ages 7 to 15 years from 15 sites from 2007 to 2009 across the US and Puerto Rico.
The researchers checked serum specimens for antibodies to MMR. About 93% of both groups had received at least the recommended 2 doses of MMR vaccine.
Many of the children were born before 1996 when the modern combined ART came into widespread use.
On average, the perinatally HIV-infected children were much less likely to have protective levels of antibodies against MMR than did the uninfected group. 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 have HIV. Also, 65% of children with HIV had immunity to rubella compared with 98% of controls, and 59% had immunity to mumps compared with 97% of controls.
Perinatally HIV-infected children who started combined ART before receiving their MMR vaccine doses were more likely to have protective levels of antibodies against all 3 diseases, especially if they had higher levels of CD4+ cells at the time they were vaccinated.
The researchers suggested that low immunity could be a result of an inadequate response to the vaccine or that the vaccine's protective effects diminished over time.
They also noted that it is possible that many other perinatally HIV-infected youth may also lack adequate immunity to MMR. They recommend that those who received their MMR vaccinations before the advent of combined antiretroviral therapy should ask their physicians if they need an additional 2 doses of the vaccine.
The study results also indicate that perinatally HIV-infected children who began combined antiretroviral therapy before receiving their MMR vaccine doses likely have adequate levels of immunity.