“Mother-to-newborn transmission of the hepatitis B virus is an enormous global problem”, says Joan Block, executive director and cofounder of the Hepatitis B Foundation. “Of the 350 million individuals living with chronic hepatitis B worldwide, most were infected at birth through perinatal transmission.”
New research, suggesting a possible treatment to prevent perinatal transmission of the hepatitis B virus (HBV), could be a vital breakthrough. Hepatitis B is the most common serious liver infection in the world and the leading cause of liver cancer. The virus is passed on through body fluids via contaminated needles or through unprotected sex. Most healthy adults who contract the virus will recover and many will be symptom-free or, at worst, suffer flu-like symptoms, jaundice, and stomach trouble. However, for those who develop chronic HBV, things are far more serious and there is a risk of liver failure, cirrhosis, and liver cancer.
There are effective vaccines for HBV and treatments are available, though access to them varies greatly across the world. Not all are considered safe for pregnant women, however. This is crucial as transmission of the virus from mother to baby is possible during pregnancy or delivery. Age of infection is key in determining the severity of HBV and almost 90% of children infected at birth will develop a chronic condition if no preventative measures are put in place.
Usually, this transmission is dealt with by treating newborn babies.
“If an infant born to an HBV-infected mother is given the first dose of the hepatitis B vaccine and one dose of hepatitis B immune globulin (HBIG) within 12 hours of birth, there is a 95% chance the baby will be protected from a chronic HBV infection,” Block says.
However, in June this year, the results of a new study at the Institute for Infectious Diseases, Southwest Hospital, Chongqing, China, were published. Findings suggest that the antiviral drug telbivudine can prevent perinatal transmission of HBV.
"If we are to decrease the global burden of hepatitis B, we need to start by addressing mother-to-infant transmission, which is the primary pathway of HBV infection," says study author Yuming Wang. "We found that telbivudine not only eliminated vertical transmission of HBV from pregnant women to theirs infants, but that it is also safe and well tolerated by women and infants."
A huge step forward
The use of medication for pregnant women with HBV is a huge step forward.
“It’s a game changer in the effort to prevent perinatal infection,” says Dr. Robert Gish, medical director of the Hepatitis B Foundation and professor consultant at Stanford University.
Block says that providing a drug to quickly reduce the viral load in pregnant women and significantly decrease the risk of perinatal infection is essential. This will break the cycle of maternal transmission.
“While there are no official medical guidelines for use of antivirals in HBV-infected pregnant women, doctors have been using some of these drugs for more than a decade because of their safe track record in preventing perinatal infection in HIV-infected women,” Block says.
The long-term influence of using telbivudine remains to be explored. At present, many doctors recommend the antiviral tenofovir (brand name Viread) for use in pregnant women with high viral loads, because of its proven safety.
Dr. Gish believes that caution on the part of doctors, rather than prejudice about pregnancy and medication, lies behind the slow progression of breakthroughs in battling HBV transmission from mother to baby.
“Obstetricians wish to be very safe in prescribing medications to pregnant women,” he says. “Thus their conservative approach. However, tenofovir is very, very safe in pregnant women during the third trimester of pregnancy.”
Giving the right care
A lack of easily accessible information can still hinder progress when it comes to finding the right treatment for pregnant women.
“I would say obstetricians, family practitioners, and pediatricians are well informed, but unfortunately other specialties are not as well informed and may need to consult online resources or with knowledgeable obstetricians,” Dr. Gish says.
The will to improve things is there and research is underway. However, increasing global access to the latest information on pregnancy and medication remains key.