Children born to HIV-positive mothers are susceptible to contracting the disease themselves, but scientists at Oregon National Primate Research Center (ONPRC) at Oregon Health & Science University (OHSU) have new evidence suggesting that newborn infection may be entirely preventable.

The researchers successfully demonstrated, in a non-human primate model, that a single dose of an antibody-based treatment given after virus exposure can prevent HIV transmission from mother to baby, provided that dose is given at the correct time. 

The study found that rhesus macaque newborns did not develop the monkey form of HIV (known as SHIV), when they received a combination of two antibodies 30 hours after being exposed to the virus. This is the first time a single dose of broadly neutralizing antibodies given after viral exposure has been found to prevent SHIV infection in nonhuman primate newborns.

However, when the antibody treatment was delayed until 48 hours after exposure, half of the baby macaques developed SHIV, even when given four smaller doses of the same antibody. 

Previous research by this group has shown that four doses of antibodies started 24 hours after exposure also prevented SHIV infection, and the current ONPRC study suggests that a three-week course of antiretroviral therapy given after virus exposure could also prevent HIV transmission to newborns.

“These promising findings could mean babies born to HIV-positive mothers can still beat HIV with less treatment,” said Nancy Haigwood, PhD, ONPRC director and a professor of pathobiology and immunology at the OHSU School of Medicine.

Antibodies aren’t toxic and can be modified to last a long time in the body, which reduces treatment frequency. This means antibody treatments may also help prevent negative side effects from the drug combination currently given to infants born to HIV-positive mothers.

Next, ONPRC scientists plan to see if different antibodies, or a combination of antibodies and antiretroviral therapy, could be even more effective. They also hope to find out whether the antibodies actually eliminate HIV or only prevent it from replicating.combination. This suggests that there is a 30-hour limit for the successful use of antibodies to prevent HIV transmission to newborns.