Early Tenofovir Treatment and Vaccination Effective in Preventing Hepatitis B Transmission During Pregnancy: JAMA

"These findings support initiating TDF treatment at 16 weeks of gestation, along with administering the HBV vaccine to infants, as an effective strategy to prevent mother-to-child transmission of HBV, particularly in regions where HBIG is unavailable," the researchers wrote.

The standard approach to preventing mother-to-child transmission of hepatitis B virus in highly viremic mothers includes maternal antiviral prophylaxis starting at week 28 of gestation, combined with an HBV vaccine series and HBIG for newborns. However, in resource-limited areas where HBIG is unavailable, Calvin Q. Pan, Guangzhou Medical University, Guangzhou, China, and colleagues sought to determine if initiating tenofovir disoproxil fumarate (TDF) at gestational week 16, along with HBV vaccinations for infants, is as effective as the standard care approach in preventing MTCT in mothers with high HBV viremia.

For this purpose, the researchers conducted an unblinded, 2-group randomized noninferiority trial at seven tertiary hospitals in China. Two hundred eighty pregnant individuals with HBV DNA levels exceeding 200,000 IU/mL were enrolled between June 2018 and February 2021. Participants were randomly assigned to receive either TDF starting at gestational week 16 with infant HBV vaccinations or TDF starting at week 28 with HBV vaccinations and HBIG for infants.

The primary outcome was the MTCT rate at 28 weeks, with noninferiority determined by a maximum absolute difference of 3%.

The study led to the following findings:

• A total of 280 pregnant individuals enrolled in the trial, with 95% completing the study.
• Among live-born infants, the MTCT rate was 0.76% (1/131) in the experimental group and 0% (0/142) in the standard care group using the last observation carried forward.
• In the per-protocol analysis, the MTCT rate was 0% in both groups (0/124 in the experimental group and 0/141 in the standard care group).
• Between-group differences met the criterion for noninferiority (0.76% and 0% with respective upper 90% CI limits of 1.74% and 1.43%).
• Congenital defects and malformations rates were lower in the experimental group (2.3%) than the standard care group (6.3%), with a difference of 4%.

"For pregnant women with HBV and high viremia levels, starting TDF at gestational week 16 alongside HBV vaccination for infants proved to be noninferior to the standard approach of initiating TDF at week 28 combined with HBV vaccination and HBIG for infants," the researchers concluded.

Reference:

Pan CQ, Dai E, Mo Z, et al. Tenofovir and Hepatitis B Virus Transmission During Pregnancy: A Randomized Clinical Trial. JAMA. Published online November 14, 2024. doi:10.1001/jama.2024.22952