Tenofovir disoproxil fumarate (TDF), an antiviral used to treat hepatitis B virus (HBV) infection, does not significantly reduce mother-to-child transmission of the virus when taken during pregnancy and after delivery, according to an NIH-funded phase 3 study.
The limited evidence of benefit from antiviral drugs to prevent mother-to-child transmission of HBV has led to conflicting practice recommendations, says Nahida Chakhtoura, MD, a member of the study team and medical officer at the National Institute of Child Health and Human Development. The World Health Organization recommends that all newborns receive their first dose of HBV vaccine within 24 hours of delivery. Those born to HBV-infected mothers also are given hepatitis B immune globulin (HBIG) for added protection. However, infants are still at risk for the virus if the mother has high levels of virus or mutated versions.
The study, conducted at 17 hospitals in Thailand, enrolled 331 pregnant women with HBV. The women received placebo or TDF at intervals from 28 weeks of pregnancy to 2 months after delivery. All 294 infants received HBIG and 5 doses of the HBV vaccine and were followed through age 6 months.
Three infants in the placebo group and none of the TDF group had HBV infection at 6 months. “Our study suggests that adding TDF to the current regimen seems to have little effect on infant infection rates when transmission rates are already low,” Chakhtoura says