Antiviral drug reduced hepatitis B transmission risk in pregnancy

Daily treatment with the antiviral drug tenofovir during the third trimester of pregnancy significantly reduced the risk of hepatitis B (HBV) transmission from mother to baby, according to new US research.

The findings of the study could potentially help to eradicate the disease, say the researchers involved.

The clinical trial was led by researchers from NYU Langone Medical Centre, who say there was previously a lack of data on the use of the drug during pregnancy. The new findings point towards the best way to care for women with hepatitis B in the later stages of their pregnancy.

Infection during the perinatal period is the most common means by which infants become infected with hepatitis B, an incurable viral infection that causes liver disease and cancer. Without intervention, 80 to 90 per cent of infants who are born to mothers infected with hepatitis B will develop a chronic infection. The current standard of care is to provide vaccine and immune globulin to reduce transmission rates.

“Preventing mother-to-child transmission is the most effective way to reduce the global burden of chronic hepatitis B infection and liver cancer,” commented Dr Calvin Pan, lead author of the study and a clinical professor of medicine at NYU Langone. “We believe that these findings will not only save many lives, but could also help to eradicate hepatitis B nationally and abroad.”

The study was conducted in five locations in China, where HBV infection is endemic. Over 200 pregnant women with a high “viral load,” defined as one million copies of the virus per milliliter in a blood sample, were enrolled in the study. Participants were randomly assigned to either a control group that received no antiviral therapy, or to a second group that received a daily dose of 300 milligrams of tenofovir in pill form, beginning at 30 or 32 weeks of pregnancy and continuing until four weeks after delivery.

It was seen that the treatment effectively reduced the viral load of the pregnant women; before delivery, 68 per cent of tenofovir-treated mothers had HBV loads below one million copies per millilitre, compared to just two per cent of non-treated mothers.

In terms of safety, the researchers found that tenofovir was well tolerated, with only one participant treated with tenofovir voluntarily withdrawing from the study due to nausea. Among the children born during the study, no significant differences between the tenofovir-treated group and the control group were found with regard to fetal development and infant growth.

The study was published on June 16 in the New England Journal of Medicine.

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