Scientists at Oregon Health & Science University School of Medicine developed a protocol capable of preventing the formation of a viral reservoir with a single dose in monkeys that had been exposed to the AIDS virus. Ultimately, this discovery may make it easier to treat babies born to HIV-positive mothers.
In 2017, 180,000 children under the age of 15 were infected with HIV worldwide, most of them by their mothers. An HIV-positive woman can transmit the virus to her child during pregnancy, childbirth or breastfeeding. To avoid this risk and to protect their own health, sick women mainly take antiretroviral therapy drugs during pregnancy. But these drugs can have many negative side effects, and researchers are concerned about the long-term consequences for babies. Now, U.S. scientists have succeeded in establishing a protocol that can prevent the formation of the viral reservoir with a single dose of antibodies in baby monkeys. However, for this to work, the treatment must be given very quickly. Their work was presented in the journal Nature Communications.
Since the antibodies are not toxic and can be modified to last a long time in the body, this reduces the frequency of treatment. A team of researchers came up with the idea of exploring its potential to replace or complement the antiretroviral therapy currently used in newborns of HIV-positive mothers as well as in HIV-positive adults.
They worked with young monkeys infected orally with SHIV-1, a similar form of the HIV virus for monkeys. By giving them a combination of two antibodies 30 hours after exposure to the virus, they found that the single-dose was enough to block its entry into immune cells. Six months later, the monkeys were still protected.
But if scientists waited 48 hours before giving four small doses of the same antibody, half of all baby monkeys would develop SHIV. Finally, monkeys who received the current standard treatment did not get sick when treatment began 48 hours after exposure to the virus.
Therefore, this study suggests that instead of the usual cocktail to which human babies born to HIV-positive mothers are exposed (various drugs for about six weeks before retesting), a much shorter antiretroviral treatment could prevent the transmission of AIDS to the newborns. This, however, can work only if the treatment is started quickly after birth.
“These promising findings could mean babies born to HIV-positive mothers can still beat HIV with less treatment,” said Nancy Haigwood, Ph.D., a professor of pathobiology and immunology in the Oregon Health & Science University School of Medicine. More research is needed to test the effectiveness of treatment in monkeys soon after birth.
Less than 1% transmission rate when mother and child are treated
In the absence of treatment, the transmission rate from an HIV-positive mother to her child is approximately 20%. These rates vary according to the mother’s clinical and immunological status. But in developed countries, sick mothers often receive clinical treatment. Treatment of the mother during pregnancy and then of the child after birth can reduce the transmission rate to less than 1%.
According to a UNAIDS report released this summer, some 82 % of HIV-positive pregnant women worldwide now have access to the drugs, an increase of more than 90 % since 2010, which has led to a 41 % reduction in new infections among children.