Prevalence of Occult Hepatitis B Infection in Hbsag Negative Blood Donors in Nairobi City County, Kenya: Case of Aga Khan Hospital

Abstract

Infections linked to blood transfusion or tissue transplants are a major challenge because of the serological window period (WP) and a latent phase exhibited by most viral infections. Hepatitis B virus (HBV) is one of the transfusion transmissible infections that is commonly screened for in donated blood across the world. This study aimed to determine the prevalence of occult hepatitis B infection (OBI) using anti-HBc antibodies as a marker in HBsAg negative donors at Aga Khan University Hospital Nairobi. This study was a laboratory-based retrospective study that tested HBsAg negative samples were tested for anti-HBc antibodies and reactive samples further tested using HBV PCR. The generated data were analyzed using Statistical Package for the Social Sciences (SPSS) version 20.0. The prevalence of OBI was calculated and expressed as a percentage. The Kappa value was calculated to determine the level of agreement between HBsAg and anti-HBc. The donor demographics and risk associated variables including age, gender, marital status and history of blood transfusion were evaluated by comparing donors with and without anti-HBc positivity. The present study population had an average age of 32 ± 8 years, with male donors dominating at n=60 (78.9%) and female n=16 (22.1%). The prevalence rate of anti-HBc was 13% during the period of the study. On further analysis of the 10 anti-HBc reactive samples with quantitative PCR, there was no detectable HBV-DNA. The majority (63.6%) of Anti-HBc reactive cases were first-time donors and blood donors with the age between 25 and 34 years being the largest age group (75.3%). Statistically, the kappa value of 0.147 suggested a slight agreement between the two methods. The Chi-square test showed no association between anti-HBc positivity with most of the sociodemographic factors. However, there was an association between anti-HBc positivity with the donors who were unmarried (X2= 8.207, at 95 CI, p<0.05). In conclusion, the inclusion of an anti-HBc marker in addition to HBsAg is much better than just using a single marker. The findings of the current study recommend all blood units should be tested for anti-HBc as an additional precautionary measure to understand the exposure status of the blood donors and to further analyze for HBV-DNA to enhance blood safety from exposed donors.