Neonatal HBV vaccination reduces the risk of liver cancer and other liver diseases in young adults in China, according to a recent study from the Cancer Institute & Hospital at the Chinese Academy of Medical Sciences, Qidong Liver Cancer Institute, and Yale School of Public Health and School of Medicine.

The researchers report long-term outcomes from the Qidong Hepatitis B intervention Study (QHBIS), a randomized controlled trial of neonatal HBV vaccination that was conducted between 1983 and 1990 in Qidong County, a rural area in China with a high incidence of HBV-related primary liver cancer (PLC) and other liver diseases. In this study, 41 rural towns (including a total of 77,658 newborns over the study period) were randomized to the intervention (HBV vaccination for all newborns) or control (no vaccination) groups, with two-thirds of the control group participants receiving a catch-up vaccination at age 10-14 years.

By collecting data on new cases of liver diseases over 30 years from a population-based tumor registry, the researchers estimated that the protective efficacy of vaccination was 84 percent for primary liver cancer (vaccination reduced the incidence of liver cancer by 84 percent), 70 percent for death from liver diseases, and 69% for the incidence of infant fulminant hepatitis. Based on survey data collected in 1996-2000 and 2008-2012 on HBsAg seroprevalence, an indicator of current hepatitis B virus (HBV) infection, they conclude that the efficacy of the catch-up vaccination on HBsAg seroprevalence in early adulthood was weak compared to neonatal vaccination (21% versus 72%). While these findings support the importance of neonatal HBV vaccination, the small number of cases of primary liver cancer and other liver diseases observed during the 30-year follow up, the length of follow-up, and the availability of incomplete data on seroprevalence all limit the accuracy of these findings.

"Neonatal HBV vaccination significantly decreased HBsAg seroprevalence in childhood through young adulthood and subsequently reduced the risk of PLC and other liver diseases in young adults," researchers said in the study. "Our results also suggest that an adolescence booster should be considered in people who were born to HBsAg-positive mothers and completed HBV neonatal vaccination series."

The findings are detailed in this week's PLOS Medicine.