Maternal exposure to dietary variables during pregnancy may influence child immunity via epigenetic programming. However, no studies have been conducted to investigate the association between the intrauterine environment and the durability of protective antibodies following hepatitis B vaccination. For a study, researchers studied the 5-year durability of protective antibody response following primary hepatitis B vaccination, as well as its link with maternal folic acid supplementation. A total of 1,461 children were followed up on who received a three-dose 10g recombinant hepatitis B vaccination at birth and did not get infected with the hepatitis B virus. The link between the 5-year persistence of protective antibodies and maternal nutrition was investigated using logistic regression and mediation analysis. 

It was found that 76.1% of 1,403 children who were not revaccinated during the follow-up showed protective hepatitis B surface antibody (anti-HBs) levels. During pregnancy, 20% of mothers did not take folate. The mediation analysis revealed that folic acid supplementation had a total effect on good persistence (odds ratio: 1.10, 95% CI: 1.03-1.17, P=0.0010), a direct effect was 1.07 (95% CI: 1.01-1.13, P=0.0128), and an indirect effect was 1.03 (95% CI: 1.00-1.06, P=0.0672); the proportion of good persistence mediated by primary response was 30.3%.

The study showed that 10 μg recombination hepatitis B immunization resulted in excellent anti-HBs persistence at year 5. Maternal folic acid supplementation may increase the survival of protective antibodies via various mechanisms.