Exclusive breastfeeding may prevent the oral transmission of HIV to babies when aided by the systemic administration of antiretrovirals, says a new study on breastfeeding and HIV published in the June 14, 2012 issue of PLoS Pathogens.
Children currently account for 15 percent of new HIV infections. Without treatment, 35 percent of babies with HIV will not live past their first birthday. Surprisingly, however, of the 15 percent of children infected with the virus, only 44 percent of babies born to HIV-positive mothers acquire the disease through breastfeeding, that is, breastfeeding and HIV account for only 6.6 percent of all new HIV infections. Despite frequent and prolonged exposure to the virus, very few infants become infected with HIV through breast milk.
To explore the paradox between a low rate of oral transmission through breastfeeding and HIV infection in children, researchers at the University of North Carolina at Chapel Hill used humanized mice to study the effects of breast milk on HIV and to study the effects of antiretroviral medications on the oral transmission of HIV.
When the mice were exposed to the virus through the breast milk from HIV-negative mothers. None of the mice acquired the disease, meaning that breast milk exhibits a complete inhibitory effect on virus infectivity. In other words, in terms of breastfeeding and HIV, breast milk destroys the HIV virus, thus preventing the oral transmission of the disease.
As Angela Wahl, PhD, a post-doctoral researcher and the lead author of the study, comments in a press release for the University of North Carolina Health Care:
“These results are highly significant because they show that breast milk can completely block oral transmission of both forms of HIV that are found in the breast milk of HIV-infected mothers: virus particles and virus-infected cells. This refutes the ‘Trojan horse’ hypothesis which says that HIV in cells is more stubborn against the body’s own innate defenses than HIV in virus particles.”
However, because breastfeeding and HIV exposure still results in 6.6 percent of new child infections, researchers also studied the inhibitory effects of antiretrovirals on the oral transmission of the virus. The mice were given antiretroviral medications for three days before and four days after exposure to the virus for a total of seven days of medication. The systemic administration of antiretrovirals provided 100 percent protection against oral HIV transmission.
The results of this study on breastfeeding and HIV are important for two reasons. First, because breast milk does destroy the virus, HIV-positive mothers should be encouraged to breastfeed, especially those mothers living in areas such as Africa were alternatives to breast milk such as infant formula prepared with contaminated water are more immediately dangerous than the possibility of HIV. Second, the oral transmission of HIV can be further prevented through the systemic use of antiretroviral medications in children of HIV-positive mothers.
As J. Victor Garcia, PhD, senior author on the study and professor of medicine in the UNC Center for Infectious Diseases and the UNC Center for AIDS Research, concludes:
“No child should ever be infected with HIV because it is breastfed. Breastfeeding provides critical nutrition and protection from other infections, especially where clean water for infant formula is scarce. Understanding how HIV is transmitted to infants and children despite the protective effects of milk will help us close this important door to the spread of AIDS.”
Do you think that this research on breastfeeding and HIV will help prevent more children from becoming infected with the virus?