ISSN 2449-8947 MicroMedicine Research Article MicroMedicine 2021; 9(1): 27-36 DOI: http://dx.doi.org/10.5281/zenodo.4641279 Sero-prevalence and associated risk factors of Hepatitis B among adults attending selected government hospitals in Nigeria Babajide Bamidele Ajayi*, Tinuola Tokunbo Adebolu, Muftau Kolawole Oladunmoye Department of Microbiology, Federal University of Technology, P.M.B. 704, Akure, Nigeria * Corresponding author: Tel: +2348061539770; E-mail: bbajayi@futa.edu.ng Received: 13 January 2021; Revised submission: 24 February 2020; Accepted: 23 March 2020 http://www.journals.tmkarpinski.com/index.php/mmed Copyright: © The Author(s) 2021. Licensee Joanna Bródka, Poland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/) ABSTRACT: Hepatitis B virus (HBV) infection is one of the major public health problems globally. This study aims to determine the frequency of occurrence of HBV infection and associated risk factors for acquisition of the disease in clinically-ill adult patients attending selected government hospitals in Ondo State, Nigeria. Seven hundred and sixty-seven (767) ill adult individuals attending five medical out-patient Departments of the hospitals who consented to the study were recruited for the investigation. A structured questionnaire which covered sociodemographic characteristics and risk factors were used for primary information. Positivity for HBV was determined using a quality assured commercial enzyme linked immunosorbent assay (ELISA) kit for the detection of Hepatitis B surface antigen (HBsAg). Of the 767 patients, 11.0% were positive for HBsAg. The prevalence rate for HBsAg positivity was higher in the males (13.5%) than the females (9.3%) (pv = 0.043). The study also revealed the highest prevalence rate of HBsAg infection among the age group 19 – 39 years with mean percentage of 17.5%. Alcohol consumption, history of HBV in the family, multiple sex partners, history of injections in road side chemist shops, and intake of traditional herbs showed significant association respectively (p < 0.05), however no significant association among individuals with history of HBV vaccination, blood transfusion and tattoo/tribal mark (p > 0.05). Conclusively, this study gives information on the prevalence rate of HBV in the community sampled to be 11.0%. This shows that HBV is endemic in Ondo State, Southwest Nigeria. Keywords: Hepatitis B Virus; Hepatitis B surface antigen; Risk factors; Sero-prevalence; Socio-demographic data. 1. INTRODUCTION Hepatitis B is a disease cause by Hepatitis B Virus (HBV) and it belongs to the genus Orthohepadnavirus in the family Hepadnaviridae. It contains deoxyribonucleic acid (DNA) as its major genetic material composed of a 27 nm nucleocapsid core which is coated by a surface antigen called the Hepatitis B surface Antigen (HBsAg) [1, 2]. As at 2015, preceding records showed that more than 2 billion people have been infected with HBV with almost 257 million people chronically infected with HBV [3, 4].