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Molecular epidemiology of hepatitis B virus vaccine variants in Singapore
Insights
Hepatitis B virus (HBV) variants can infect infants despite immunoprophylaxis. A common variant features an amino acid substitution (Gly to Arg at position 145) in the HBV surface protein, raising concerns for detection and vaccination.
Area of Science:
- Virology
- Immunology
- Public Health
Background:
- Perinatal transmission of Hepatitis B virus (HBV) remains a challenge despite combined immunoprophylaxis using Hepatitis B immunoglobulin and licensed vaccines.
- The emergence of HBV variants capable of evading immune responses poses a significant threat to prevention strategies.
Purpose of the Study:
- To investigate the prevalence and characteristics of HBV variants in infants born to carrier mothers.
- To identify specific mutations associated with immune evasion in perinatal HBV infections.
Main Methods:
- A large-scale study was conducted on infants born to HBV carrier mothers in Singapore.
- Viral sequencing was employed to detect and characterize HBV variants, focusing on mutations in the outer protein coat.
Main Results:
- Several HBV variants were detected in the studied infant cohort.
- The most frequent variant identified exhibited a single amino acid substitution (Glycine to Arginine) at position 145 of the HBV surface protein.
- This specific mutation (G145R) has been reported globally, indicating a widespread issue.
Conclusions:
- The G145R substitution in HBV variants is a significant cause for concern regarding diagnostic detection.
- The emergence of these antibody escape mutants may compromise the efficacy of current and future hepatitis B vaccination programs.
- Further research is needed to monitor these variants and adapt prevention strategies accordingly.
Abstract:
Perinatal infection with variants of hepatitis B virus occurs despite combined immunoprophylaxis with hepatitis B immunoglobulin and currently licensed plasma-derived and recombinant yeast hepatitis B vaccines. Several variants have been detected during a large study of infants born to carrier mothers in Singapore. The most frequent variant was a virus in which a single amino acid substitution Gly to Arg occurred at amino acid position 145 of the outer protein coat of the virus. Similar mutations have been described in Italy, Japan, the USA and a number of other countries. The emergence of antibody escape mutants is a cause for concern for the detection of virus and possibly for future immunization programmes.