Antiviral treatment of HBV positive pregnant women: an additional tool to reduce perinatal transmission

Abstract

In a recent study published in New England Journal of Medicine, Pan and colleagues 1 faced an important aspect for prevention of hepatitis B virus (HBV) infection: antiviral treatment with Tenofovir (TDF) during pregnancy to reduce perinatal transmission. This route of infection plays a crucial role for global diffusion of HBV, with frequency of chronic infection in mother-to-childtransmission (MTCT) of 90%.The results by Pan and colleagues show that TDF treatment during pregnancy significantly reduces the transmission rate compared to the standard prophylaxis recommended by World Health Organization (WHO), 2 that leaves a residual HBV transmission mostly in highly viremic mothers (>200,000 IU/mL HBV-DNA). Thus, reduction of the viral load at delivery by antiviral treatment is an attractive possibility in reducing MTCT. Indeed, in a recent simulation model of the global HBV epidemic, scaling up the use of peripartum antivirals (to 80% of HBeAg positive mothers), together with other interventions, was indicated as an important strategy to avert 7.3 million deaths between 2015 and 2030. 3 Earlier reports have shown conflicting results but, according to recent WHO guidelines, 2 quality scores of some studies were low, highlighting the need for further, more carefully designed ones. Pan et al. performed a multicenter, open-label, randomized, parallel-group study, enrolling 200 highly viremic mothers. The reliability of the results was significantly improved by a proper experimental design. The primary outcomes (transmission rate and birth defects) were assessed at 28 weeks after birth, a longer follow-up than in previous studies. In addition, monitoring of maternal viral load convincingly demonstrated, in 68% mothers, reduction of viremia at delivery below the 200,000 IU/mL, considered to be the threshold value for significant decrease of MTCT.

The effectiveness of 20 μg hepatitis B vaccine used for the prevention of HBV vertical transmission

“…Previous studies have reported that antiviral therapy during pregnancy can effectively reduce the serum HBV DNA level, even reaching the serological conversion of HBeAg and HBeAb 30 , 31 . In this study, the HBeAg positive rate of pregnant women who received antiviral therapy was significantly higher ( P = 0.034) than those who did not (36.8% VS 26.4%).…”