Molecular detection of hepatitis B virus genotype E with immune escape mutations in chronic hepatitis B patients on long-term antiviral therapy in Jos, Nigeria

Joseph Anejo-Okopi*, Edith Okeke, Pantong M. Davwar, Chika Onwuamah, Harris Onywera, Patience Omaiye, Mary Duguru, Ocheme J. Okojokwu, Otobo I. Ujah, Bulus Jonathan, Chima A. George, Ramyil S. Crown, Fiyaktu B. Yakubu, Judith O. Sokei, Leona C. Okoli, Onyemocho Audu, Seth C. Inzaule, Isaac O. Abah, Patricia Agaba, Oche O. AgbajiAtiene S. Sagay, Claudia Hawkins

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Background: Previous studies in Nigeria have reported the presence of hepatitis B virus (HBV) genotype E and the availability of immune escape mutants. There is a paucity of data on chronic patients on long-term antiviral therapy for HBV infection. Objective: This study assessed HBV genotypes and drug resistance variants among patients with chronic HBV infection receiving tenofovir in Jos, Nigeria. Methods: This cross-sectional study consecutively enrolled 101 patients (51 with HIV/HBV co-infection and 50 with HBV infection only) on antiviral therapy from February 2018 to May 2019 at four hospitals in Jos, Nigeria. DNA quantification of HBV was performed on all samples; 30 samples with detectable viral load were selected for genotyping using Sanger sequencing by targeting the full-length sequences of reverse transcriptase gene of the HBV genome. Phylogenetic analysis was performed with reference sequences from GenBank. Escape mutant and drug resistance analysis were performed using HBV drug resistance interpretation and Geno2pheno. Results: Only 30 (29.7%) of the 101 study participants had detectable HBV DNA. Of these, six (20.0%) isolates were successfully amplified and sequenced. The identified genotype was E, including escape mutations L127R (16.7%) and G145A (16.7%). Conclusion: This study revealed exclusive dominance of genotype E in Nigeria. The S gene mutations G145A and L271R are known to be associated with modified antigenicity and impaired serologic assays, which may cause false negatives in the detection of anti-HBV surface antigen. The presence of mutants that are associated with vaccine immune escape may also have diagnostic and vaccine immune response implications.

Original languageEnglish (US)
Article numbera1677
JournalAfrican Journal of Laboratory Medicine
Issue number1
StatePublished - 2022


  • antiviral drug resistance
  • chronic hepatitis B
  • genotyping
  • hepatitis B virus (HBV)

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Medical Laboratory Technology
  • Clinical Biochemistry


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