A nationwide hepatitis B immunization program in Taiwan improved risk and mortality rates for liver disease continuously during a 30-year period, according to recent results.
Researchers evaluated the results of the immunization program, initiated during July 1984. Initially, the program only included infants born to high-risk mothers who tested positive for HBV surface antigen, but coverage extended to all newborns during July 1986, to preschool children during July 1987 and to all primary school children between 1988 and 1990. Coverage rates from 1984 to 2010 were 88.8% to 96.9%.
Infants born between 2009 and 2011 had significantly improved sex-adjusted RRs and mortality rates for infant fulminant hepatitis (IFH) compared with those born between 1977 and 1980 (aRR=0.03; 95% CI, 0.01-0.24; mortality rate=0.19 deaths per 100,000 person-years compared with 5.76; P<.01). The decrease was greatest between 1981-1984 and 1985-1988, which coincided with the launch of the program, and between 1989-1992 and 1993-1996, coinciding with a change from the use of plasma-derived vaccines to recombinant HBV vaccinations in 1992.
Mortality rates for chronic liver disease (CLD) and hepatocellular carcinoma (HCC) also decreased with time, declining from 0.65 deaths per 100,000 person-years from 1977-1980 to 0.02 from 2001-2004 for CLD (aRR=0.11; 95% CI, 0.02-0.8), and from 0.81 in 1977-1980 to 0.05 in 2001-2004 (aRR=0.08; 95% CI, 0.02-0.34) for HCC. Hepatocellular carcinoma incidence among patients aged 5 to 29 years also declined (aRR=0.2; 95% CI, 0.06-0.65 from 2001-2004 vs. 1977-1980).
“This long-term, high-coverage immunization program was associated with lower IFH mortality through increasing individual and herd immunity of vaccinated cohorts,” the researchers wrote. “The national HBV therapy program launched in November 2003 may also be contributing to the reduction in risk of IFH, CLD and HCC; however, this contribution is likely minimal, because few members of the study cohorts were eligible for therapy. Hepatitis B virus immunization in infancy has been associated with a reduction in the risk of IFH, CLD and HCC in Taiwan.”
Disclosure: Researcher Chien-Jen Chen, ScD, reported numerous financial disclosures.