Occult hepatitis B virus infection in hepatitis B vaccinated children in Taiwan

• Published in: Journal of hepatology Vol. 50; no. 2; pp. 264 - 272
• Main Authors: Mu, Shu-Chi, Lin, Yu-Min, Jow, Guey-Mei, Chen, Bing-Fang
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.02.2009; Elsevier
• Subjects: Amino Acid Sequence; Base Sequence; Biological and medical sciences; Child; Child, Preschool; DNA, Viral - blood; Female; Gastroenterology and Hepatology; Gastroenterology. Liver. Pancreas. Abdomen; HBV vaccination; Hepatitis B - epidemiology; Hepatitis B - prevention & control; Hepatitis B Surface Antigens - blood; Hepatitis B Surface Antigens - chemistry; Hepatitis B Surface Antigens - genetics; Hepatitis B Surface Antigens - immunology; Hepatitis B Vaccines - immunology; Hepatitis B virus - classification; Hepatitis B virus - genetics; Human viral diseases; Humans; Infant; Infectious diseases; Male; Medical sciences; Molecular Sequence Data; Occult HBV infection; Phylogeny; Polymerase Chain Reaction; Pre-S deletion; Prevalence; Protein Precursors - chemistry; Protein Precursors - genetics; Protein Precursors - immunology; Taiwan - epidemiology; Vaccination; Viral diseases; Viral hepatitis; Asia; Taiwan; aa; Occult HBV; amino acid; hepatitis B virus; nt; nucleotide; Pre-S deletion; Occult HBV infection; HBV vaccination; HBV; oHBV; PCR; polymerase chain reaction; Human; Vaccination; Hepatic disease; Infection; Prevention; Viral hepatitis B; Immunoprophylaxis; Viral disease; Gastroenterology; Deletion; Digestive diseases; Child
• ISSN: 0168-8278; 1600-0641
• DOI: 10.1016/j.jhep.2008.09.017

Background/Aims Presence of occult HBV infection in HBV vaccinated children remains largely unknown. The aim of this study was to investigate the prevalence of occult HBV infection among HBV vaccinated children in Taiwan. Methods Forty-six HBsAg negative sera from vaccinated children were enrolled randomly. HBV serum markers were detected by ELISA, and the titers of HBV DNA were determined by quantitative real-time PCR. Pre-S, S and pre-core/core genes were amplified by nested PCR and analyzed. Results Anti-HBs was detected in 23 (50%) children, and the positivity decreased according to age. Five (10.9%) children were classified into occult HBV infection by positivity of nested PCR in at least two regions; they had a low titer (mean titer 1.60 × 104 copies/ml). Sequence analyses of S gene showed occult isolates were variants; no G145R but C139S vaccine escape mutant was found. Variation and deletion were found in pre-S region; pre-S deletion was more frequent in 3′ terminus of pre-S1 which leads to loss of immune epitopes and function sites. Conclusions This pilot study indicates that the prevalence of occult HBV infection is 10.9% in HBV vaccinated children. Since this is a small study, a study of a large population is needed to confirm the findings herein.