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HBV DNA seroprevalence increases among adult patients despite vaccination

Patients vaccinated against HBV were protected through adolescence, but seroprevalence for HBV DNA and antibodies to hepatitis B antigens increased among older participants in a recent study.

Researchers measured levels of hepatitis B surface antigen (HbsAg) and antibodies to hepatitis B core (anti-HBc) and surface (anti-HBs) antigens in 1,214 serum samples collected from Taiwanese patients aged 0.6 to 87.8 years. HBV DNA levels were measured among HBV-vaccinated patients who tested positive for anti-HBc or HBsAg (n=65).

Patients who were born after Taiwan’s HBV vaccination program began in 1984 had significantly lower HBsAg and anti-HBc seroprevalence compared with older patients (1.0% vs. 9.3% for HBsAg, 2.3% vs. 43.9% for anti-HBc, P<.001). Investigators observed increasing seroprevalence of anti-HBc and isolated anti-HBs according to age: Anti-HBc was present in 0.4% of patients aged 10 to 14 years, 1.9% of those aged 14 to 18 years and 8.1% of those aged 18 to 21 years (P=.0135), and anti-HBs was in 43.7%, 55.4% and 59.6% of these patients, respectively (P=.0093). HBsAg seroprevalence also was observed in 2.0% of patients aged 18 to 21 years, compared with zero patients in either of the other two age groups (P=.017).

HBV DNA seroprevalence was more common among patients aged 18 to 21 years, with 3.0% in the age group testing positive, compared with 0.2% among younger patients (P=.002). Fully vaccinated patients (those who received three or more doses) had similar seroprevalence rates (5.7% vs. 0.3%, P<.001). Isolated anti-HBs was also significantly more common among vaccinated patients (59.5% vs. 39.3%, P<.001), but the rate decreased according to age, from 75.0% among participants younger than 6 years to 43.7% among those aged 10 to 14 years (P<.0001).

Among eight fully vaccinated participants who tested positive for HBV DNA via real-time PCR, five carried S gene mutations. Investigators noted that this indicated an increase in the prevalence of surface mutations after adolescence that requires careful monitoring.

“Universal vaccination effectively controls HBV infection in children and adolescents,” the researchers wrote. “However, after adolescence, there is a significant increase in the seroprevalence of anti-HBs, anti-HBc and HBV DNA, indicating that new preventive strategies are needed for adults. Monitoring the prevalence of HBV infection by sensitive HBV DNA assays in subjects beyond adolescence in [the] postvaccination era is mandatory.”