Background: The implementation of universal hepatitis B virus vaccination programs had led to significant reduction in the incidence of acute and chronic HB infection, liver cirrhosis and hepatocellular carcinoma. However, this success is being threatened by the discovery of HBV vaccine breakthrough infection and vaccine associated nonresponse.
Aim: Of this cross-sectional study was to evaluate the effectiveness of zero dose HBV vaccine on prevention of HBV breakthrough infection among vaccinated Egyptian infants and to study the role of IL4 SNPs as a cause of vaccine non-responsiveness.
Methods: The present study was carried out on 77 infants their age ranged from 6 to 12 months; all of them received HBV vaccine according to the new schedule as the Egyptian Public Health Authority recommend, the first dose was administered within the first 24 hours after delivery. Their serum samples were screened for the presence of HBsAg and HBV-DNA as markers of infectivity. Their HBsAb level was detected to assess their immunity and Cytokine gene analysis to identify IL4 gene polymorphism associated with non-responsiveness to HBV vaccination.
Results: It was found that all infants were negative for HBV DNA but HBsAg was positive in 61 out of 77 (79.2%). HBsAg positivity increases after the fourth dose of vaccination and persists for two, four and even six months after vaccination in23.4%, 9.1% and 11.7% of vaccinated infants respectively. There was positive correlation between HBsAg positivity and HBs antibody titer as HBsAg positivity was 60% in non-responders, 77% in low responders and 81% in high responders, there was no statistically significant association between HBsAg positivity and the mode of delivery. The presence of IL4 SNPs especially SNP3 is correlated with the non and low responders to HBV vaccine, however this correlation is statistically non-significant.
Conclusion: HBV infection rates have significantly reduced after the introduction of the zero-dose vaccination. The presence and persistence of positive HBsAg with negative HBV-DNA after vaccination may be vaccine induced and not HBV breakthrough infection.
Published Date: 2021-03-31; Received Date: 2021-03-10