February 9, 2011
"Babies who are exposed to HIV at birth but don't become infected with the virus have lower levels of antibodies to diseases such as whooping cough, tetanus and pneumococcus," according to a study published in the Feb. 9 issue of the Journal of the American Medical Association (JAMA), HealthDay News/U.S. News & World Report (2/8). The findings "might explain in part why uninfected babies born to women with HIV have a higher risk of illness and death early in life," according to a press release by the Imperial College of London, whose researchers helped lead the study.
For the study, antibody levels of 109 HIV-positive and HIV-negative pregnant women in Khayelitsha, South Africa, were measured before birth, and the antibody levels of their infants measured after birth, according to the release. "They also assessed how the babies responded to routine vaccination by measuring the babies' antibody levels at four months, after they had received their routine vaccines," the release states (2/9).
Before the infants were vaccinated, the research shows that "[o]f infants exposed to HIV before birth without becoming infected themselves, 17 percent had antibody levels thought to protect against Haemophilus influenza type B, or HiB, compared with 52 percent of infants without exposure. ... Twenty-one percent of those exposed [to HIV] had antibodies against hepatitis B compared with 54 percent of unexposed babies," the study authors reported, according to Bloomberg. "HIV-positive mothers had lower levels of antibodies to HiB and pneumococcus, and not to whooping cough or tetanus, the researchers found. HiB can cause meningitis and pneumonia," the news service adds (Ostrow, 2/8).
After being vaccinated, the researchers "found that HIV-exposed uninfected infants compared with HIV-unexposed infants had robust antibody responses following vaccination, with higher antibody responses to pertussis and pneumococcus," according to a JAMA press release (2/8).
"Once the HIV-exposed, uninfected babies received their routine vaccinations, they had antibody levels similar to, or higher than, HIV unexposed infants, meaning that they were likely to be well protected by vaccination," Imperial College of London's Christine Jones, who was the lead author of the study, said, according to Bloomberg. "More research is needed to establish whether babies exposed prenatally to HIV could be better protected against infections through earlier vaccination, or through vaccine shots given to mothers before the children are born, [she] said" (2/8). The study authors concluded: "Targeted vaccination strategies may be required in HIV-infected women and their infants" (Jones et al., 2/9).
Agence France-Presse describes what the findings might mean for the growing number of HIV-exposed infants worldwide. While "[b]irths of HIV-positive babies have dropped dramatically in the past decade due to medications that mothers can take during pregnancy to prevent transmission ... infectious disease remains a major killer of children under five, killing close to six million children globally each year," the news service writes (2/8).
Bloomberg includes comments on how the findings of the trial could impact future vaccination programs targeting HIV-positive mothers and their HIV-exposed infants by Michael Brady, chairman of the Department of Pediatrics at National Children's Hospital in Columbus, Ohio, and Bruce Hirsch, an attending physician at North Shore University Hospital in Manhasset, New York, who were not involved in the study (2/8).