Background: Occult hepatitis B infection (OBI) has been described in various clinical settings including after hepatitis B virus (HBV) immunization. The purpose of study was to characterize the prevalence of OBI among immunized children from a subset of general population and the parents of OBI-positive cases. Methods: Sera of 1200 children from general population who have been previously immunized by HBV vaccine were assayed for anti-HBs. 660 were randomly selected for HBV DNA testing by different polymerase chain reaction (PCR) methods and were analysed by direct sequencing on surface genes. Results: None of participants were positive for HBsAg and anti-HBc. 549 (45.7%) and 651 (54.3%) cases had anti-HBs > 10 mIU/mL (responders) and < 10 mIU/mL (nonresponders) respectively. Of 660 selected specimens, 91 (16%) of children were positive for OBI. 23 (25.2%) and 68 (74.8%) of HBV DNA positive cases were belonged to responders and nonresponders, respectively, showing significant difference (P <.001). The mean levels of anti-HBs in OBI-positive and OBI-negative groups, showed no considerable variations. The mean viral load for OBI-positive cases showed substantial differences between responders and nonresponders (P =.007). Of 49 parents (98 individuals) of OBI-positive children 11 (22%) and 18 (36%) were positive for anti-HBc and anti-HBs respectively. Molecular testing was positive in 32 subjects (16 couples, 32.6%). In total, 6 mothers and 11 fathers were positive for OBI. Conclusion: A proportion of OBI-positive vaccinated children could be existed in different populations. This finding could be arisen from vertical HBV transmission or vertical OBI possibly from their parents.
Bibliographical noteFunding Information:
Funding information The study was supported by a grant from the National Institute for Medical Research Development (NIMAD) (grant No: 943595). Also supported by Tehran University of Medical Sciences (grant No: 94-04-27-30801). The supporters of the study had no role in the design and conduction of the study, analysis and interpretation of the data and preparation, review or approval of the manuscript. Corresponding author (principal investigator) had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Authors thank Research Center for Clinical Virology a for their cooperation in the study.
© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
- HBV immunization
- HBV vertical transmission
- occult hepatitis B infection
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