Mother-to-child transmission of hepatitis B occurs frequently either in the uterus, through placental leakage, or through exposure to blood or blood-contaminated fluids at or around the time of birth. This form of transmission (sometimes called “vertical transmission”) is believed to account for between a third and a half of hepatitis B infections, and so a way to easily prevent it would do a huge amount to reduce the number of people living with hepatitis B in the long term.
Early results from a randomised Chinese clinical trial have shown a possible way to make this happen. Using the medication known as maternal tenofovir disoproxil fumarate (TDF) in combination with infant vaccination against hepatitis B completely eliminated vertical transmission of the hepatitis B virus. This was the case even when the mothers had extremely high loads of hepatitis B virus in their blood.
Another exciting aspect to this trial is that there was no need to use hepatitis B immunoglobulin, something which is often used to give people a temporary immunity against hepatitis B in high-risk situations, or immediately after exposure as a form of prophylaxis. Supply of this immunoglobulin is often very limited, and so anything which reduces demand is extremely helpful.
The mothers themselves also showed dramatically lowered levels of hepatitis B in their blood at the time of birth, and there was no increase in the risk of congenital defects.
Dr Calvin Pan told an audience at The Liver Meeting, one of North America’s largest hepatology conferences, that the findings showed that use of this two-part treatment “could effectively prevent transmission, which is comparable to the current standard of care, with no safety signals.”
This sort of 100% success rate is extraordinarily rare in medical trials, and so further larger trials are now needed to confirm and extend these results.