Antiretroviral therapy of pregnant women and antiretroviral treatment of infants have greatly reduced the rate of mother-to-child HIV transmission, also referred to as vertical transmission. Nevertheless, although these improved rates have occurred in some countries, vertical transmission rates remain relatively high in others. This may be due to multiple factors, including access to testing, care and antiretroviral therapy, adherence to antiretroviral therapy during pregnancy and breastfeeding, and potential HIV drug resistance. In order to evaluate the factors that result in vertical transmission, researchers compared variables that resulted in HIV outcomes in infants from pregnant and breastfeeding mothers from 14 sites in 7 countries.
The researchers analyzed plasma from mothers and their infants at or near the time of infant HIV diagnosis to determine whether their infections were resistant to currently used drugs. Additionally, the researchers did long-term analysis of the HIV genetic structure in the infants so that they could analyze possible drug resistance later on. Their findings showed that maternal HIV drug resistance was not associated with in utero vertical transmission. However, both maternal viral load and HIV drug resistance were associated with vertical transmission during breastfeeding. These findings support efforts to reduce and eliminate HIV reproduction during pregnancy and have implications for re-evaluating appropriate antiretroviral treatment for breastfeeding infants.
Reference: Boyce et al. Maternal Human Immunodeficiency Virus (HIV) Drug Resistance Is Associated With Vertical Transmission and Is Prevalent in Infected Infants, Clinical Infectious Diseases, 2021; ciab744.