Hepatitis B vertical transmission rates leave room for improvement

Last Updated: 2015-04-20

By Will Boggs MD

NEW YORK (Reuters Health) - The already low rates of transmission of hepatitis B virus (HBV) from mothers to infants could be reduced even further with closer adherence to existing guidelines, researchers say.

"Preventing perinatal hepatitis B transmission is a critical part of the national strategy to eliminate hepatitis B in the U.S.," Dr. Sarah Schillie, from the Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, told Reuters Health by email.

"It's important that health care providers understand and follow national guidelines that include the universal screening of pregnant women for hepatitis B during pregnancy, case management of mothers with hepatitis B and their infants, provision of immunoprophylaxis for infants born to infected mothers, and routine vaccination of all infants with the hepatitis B vaccine series (with the first dose administered at birth)," she said.

Immunoprophylaxis is reported to be 85% to 95% effective in preventing perinatally acquired chronic HBV infection for infants born to hepatitis B surface antigen (HBsAg)-positive women.

Dr. Schillie and colleagues analyzed data from five of the 64 U.S.-funded Perinatal Hepatitis B Prevention Programs during 2007-2013.

Only 1.1% of the 9252 infants with available information acquired perinatal HBV infection, according to the April 20 Pediatrics online report.

Infection rates were much higher for infants who received fewer than three doses of hepatitis B vaccine (6.7%) than for those who received three or more doses (1.1%).

Other factors associated with higher rates of vertical transmission of HBV included Asian/Pacific Islander race/ethnicity, higher viral loads, maternal positivity for hepatitis B e-antigen (HBeAg), and younger maternal age.

"Before the widespread availability of immunoprophylaxis, the proportion of infants born to HBsAg-positive women acquiring HBV infection was 30% for infants born to HBeAg-negative women and 85% for infants born to HBeAg-positive women," the researchers note.

"Perinatal hepatitis B transmission can be further reduced by identifying pregnant women at the greatest risk for transmitting the virus to their infants and providing them with antiviral therapy," Dr. Schillie said. "Those at the highest risk could include mothers with high viral loads or who are hepatitis B e-antigen positive."

Dr. Ravi Jhaveri, from the University of North Carolina at Chapel Hill School of Medicine, who wrote an accompanying editorial, told Reuters Health by email, "We all need to recognize that there are women with chronic HBV that are at high risk for prophylaxis failure. We can do a pretty good job of predicting (and intervening) ahead of time, but we need to put the systems in place to do it."

Dr. Heather Patton, from the Southern California Permanente Medical Group, San Diego, told Reuters Health by email, "Whether or not the rate of appropriately timed immunoprophylaxis of 95% reported in this study is seen as encouraging or discouraging is in the eye of the beholder. I think we would hope that among centers specifically studying perinatal transmission of HBV that 100% of infants would receive therapy within the recommended time frame. That said, the receipt of therapy within 12 hours was not found to be associated with perinatal transmission of HBV (whereas completion of the entire series of HBV vaccination did appear to be important)."

"I think that in an era where we are utilizing electronic medical records for patient care, universal systems could be implemented to ensure that we are performing appropriate prenatal testing to identify HBsAg-positive mothers as well as delivering recommended immunoprophylaxis to infants born to these mothers within the recommended time frame," Dr. Patton said.

"By implementing automated orders in electronic medical record systems, we can come closer to the 100% mark by eliminating the need to rely on health care providers to remember to order hepatitis B testing during pregnancy and . . . vaccination when this testing is positive," she said.

She added, "I would also emphasize the fact that despite effective antiviral therapies, chronic HBV infection remains an important source of morbidity and mortality via decompensated liver disease and hepatocellular carcinoma. Our best shot at reducing the future burden of disease from HBV is through appropriate prenatal testing and perinatal management of HBV."

Dr. Wolfram Gerlich, from Justus Liebig University Giessen's Institute for Medical Virology in Germany, told Reuters Health by email, "A more convincing approach would be to change the current HB vaccines used in the USA. The subtype dependence of the HB vaccines has been neglected for long. The vaccine protects best against the HBV genotype with HBsAg subtype adw2 of the Caucasian population of the USA and Northern Europe. Most of the vaccination failures occur with the HBsAg subtype adr of the Far East. But the major vaccine producers in Europe and the USA reject to widen their HBsAg subtype spectrum. Vaccines with HBsAg subtypes other than adw2 are available in Korea (adr) and Russia (ayw2)."

"Another weakness of the current vaccines is the lack of the viral attachment and entry factor preS1, which induces strongly neutralizing antibodies against all HBsAg subtypes," Dr. Gerlich said. "A successfully tested preS1-containing vaccine (Sci-B-Vac) is available in Israel and used there for vaccination of children of HBV-positive mothers. Preliminary data from Palestine suggest that Sci-B-Vac is superior to the standard vaccine in preventing mother-to-child transmission."

The CDC partially supported this research. The authors declared no conflicts of interest.

SOURCE: http://bit.ly/1E2PnS0 and http://bit.ly/1Iy9W8A

Pediatrics 2015.