Higher rate of anti-HBs disappearance with recombinant versus plasma HBV vaccine
medwireNews: The infant recombinant yeast hepatitis B virus (HBV) vaccine has long-term efficacy, but the rate of disappearance of protective antibodies against hepatitis B surface antigen (HBsAg) is higher than with the plasma-derived vaccine, shows a study of Taiwanese university students.
If the findings are confirmed, they could signal the need for booster shots for individuals given the recombinant vaccine, especially for high-risk groups, say Chyi-Feng Jan (National Taiwan University Hospital, Taipei) and co-workers.
The study included 38,377 first-year students from a university in northern Taiwan who underwent a mandatory health assessment between 2003 and 2015.
Of these, 58.8% were born between July 1986 and April 1992, and thus would have received the plasma vaccine, whereas the remaining 41.2% were born between March 1993 and December 1997, when the recombinant vaccine was used. Individuals born in the intervening period (May 1992–February 1993), when either vaccine may have been used, were excluded to ensure consistency within the groups.
An average of 18.2 years after vaccination, the HBsAg seroprevalence rate was significantly lower in the group that received the recombinant vaccine than the plasma one, as was the natural HBV infection rate, at 0.3% versus 1.5%, and 1.3% versus 3.7%, respectively (p<0.001 for both).
However, the proportion of individuals seropositive for antibodies against HBsAg (anti-HBs) was also lower in the recombinant than the plasma vaccine cohort, with rates of 30.9% versus 43.6%.
Multivariate analysis adjusting for age and gender confirmed that receipt of the recombinant versus plasma vaccine was significantly associated with a reduced risk for HBsAg seropositivity and developing natural HBV infection (odds ratios [ORs]=0.29 and 0.35, respectively; p<0.001 for both), but also with a reduced likelihood of retaining anti-HBs during young adulthood (OR=0.61; p<0.001).
Jan et al comment that the observed differences could be due to innate variations between the vaccines, explaining that previous research indicates that the plasma-derived vaccine may have higher immunogenicity than the recombinant vaccine at a comparable weight and dose.
Other reasons could be differences in the types or dosages of vaccines used or a potentially higher rate of re-exposure to HBV among those who received the plasma vaccine, they further speculate in Liver International.
The team concedes, however, that the underlying causes and molecular mechanisms need “to be explored further.”
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