Antiviral May Not Reduce Mother-to-Child Hepatitis B Transmission

Adding tenofovir disoproxil fumarate to prevention regimens may not effectively stop hepatitis B virus transmission to infants.

Mother-to-child transmission of viruses is a public health concern, especially for serious infections such as HIV, human papillomavirus, and hepatitis.

Related Coverage: What Influences Mother-to-Child Transmission of HIV?

A study published by the New England Journal of Medicine suggests that administration of the antiviral tenofovir disoproxil fumarate (TDF) during pregnancy and after delivery does not help lower the risk of mother-to-transmission of hepatitis B virus (HBV).

The phase 3 clinical trial, which was funded by the National Institutes of Health, explored whether adding TDF to standard prevention measures, including administering the HBV vaccine and protective antibodies, may drop transmission rates.

“Limited evidence of the benefit of using antiviral drugs to prevent mother-to-child transmission of hepatitis B has led to conflicting practice recommendations around the world,” said researcher Nahida Chakhtoura, MD. “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.”

HBV can be transmitted during delivery and can result in long-term health issues, including liver disease and cancer. There is currently no cure for HBV, but patients typically take antivirals for their entire lifespan, highlighting the importance of prevention.

The World Health Organization suggests that newborns receive the first dose of the HBV vaccine within 24 hours, and those born to HBV-positive mothers receive hepatitis B immune globulin (HBIG); however, mother-to-child transmission still occurs due to high viral load and viral mutations, according to the study.

Included in the current study were 331 pregnant women with HBV living in Thailand who received either placebo or TDF from 28 weeks of pregnancy to 2 months post-delivery. All patients received HBV preventative care, which includes HBIG at birth and 5 doses of the vaccine by age 6 months. There were 294 infants followed through age 6 months.

The authors discovered that 3 infants in the placebo cohort were HBV-positive at age 6 months, while there were no HBV-positive infants in the TDF cohort.

Due to the low rate of HBV in both groups, the authors said that adding TDF to preventative guidelines may not be useful in preventing mother-to-child transmission of HBV, according to the study.

The researchers noted the lower transmission rate in Thailand may be related to the doses of the HBV vaccine in infants, reduced rates of amniocentesis, and lower rates of caesarian deliveries, according to the study. Additionally, reduced prevalence of mutated viruses, and thus higher vaccine efficacy, could have led to the low transmission rate, the authors noted.

“We observed no treatment-related safety concerns for the mothers or infants and no significant differences in infant growth,” said lead author Gonzague Jourdain, MD, PhD. “These safety data also are relevant for pregnant women receiving TDF as part of HIV treatment or HIV pre-exposure prophylaxis.”