Prevalence of occult hepatitis B infection among Treatment-naive HIV/AIDS Patients in Sub-Saharan Africa: A Protocol for Systematic Review and Meta-analysis.

The dual burden of human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infections remains a major public health challenge in Sub-Saharan Africa (SSA). Both viruses share similar modes of transmission, including exposure to infected blood, unprotected sexual contact, and perinatal transmission, which explains the high prevalence of HIV/HBV co-infection in the region. ¹ Chronic infection with either virus significantly contributes to morbidity and mortality in SSA, where healthcare resources are limited and preventive strategies often face logistical barriers. The natural history of HBV infection is determined by complex interactions between viral replication and host immune responses. Traditionally, the absence of hepatitis B surface antigen (HBsAg) was considered evidence of viral clearance or remission.¹ However, in the 1970s, the phenomenon of occult hepatitis B infection (OBI) was first described among blood donors who tested HBsAg-negative but hepatitis B core antibody (anti-HBc)-positive, revealing ongoing viral persistence despite apparent recovery.¹,² The World Health Organization (WHO) recommends the diagnosis of HBV infection primarily through enzyme immunoassays (EIA) or rapid diagnostic tests (RDTs) that detect HBsAg.³ Nevertheless, these methods may fail to identify OBI cases, as viral replication can persist at low levels undetectable by standard serological assays.⁴ The detection of covalently closed circular DNA (cccDNA) using nucleic acid testing (NAT) on liver tissue samples remains the gold standard for confirming OBI.⁴ OBI is characterized by the persistence of HBV DNA below 200 IU/L in individuals who are serologically negative for HBsAg following recovery from acute or chronic infection. ⁵ Genetic variants such as S-escape mutations and pre-S1/pre-S2 deletions may alter surface antigen expression, leading to false-negative HBsAg results in standard screening assays. ⁷-8,4 Globally, the prevalence of OBI ranges widely, from 1% to 90.9%, depending on HBV endemicity, host immune status, and diagnostic sensitivity.9 Despite increasing research interest, the prevalence and clinical relevance of OBI among antiretroviral therapy (ART)-naïve HIV patients in SSA remain poorly characterized.¹0 Studies have reported prevalence rates of 5.6% among HBsAg-negative individuals and 5.3% among ART-naïve HIV-positive patients.¹1 Similarly, Salia et al. documented a 4.7% OBI prevalence among HBsAg-negative, ART-naïve HIV patients in Ghana.¹2 Emerging evidence suggests that OBI is not a benign condition; it has been linked to advanced liver disease, particularly hepatocellular carcinoma (HCC), and may contribute to HBV transmission.¹3 Consequently, the global burden of OBI, especially among immunocompromised groups such as ART-naïve HIV patients, may be underestimated. This is particularly concerning in low- and middle-income countries (LMICs), where limited access to HBV DNA testing hampers accurate diagnosis and monitoring. Rationale Despite notable advances in the prevention and management of HIV and HBV infections, OBI continues to receive minimal attention in clinical practice, especially among individuals who are HIV-positive and yet to commence ART14,15. The coexistence of HIV and HBV presents a complex clinical challenge, as HIV-associated immune suppression may enhance HBV replication, hastening the onset of liver-related complications 16. Current HBV diagnostic approaches in SSA rely solely on HBsAg detection are insufficient, as they fail to identify individuals harboring occult infections, thereby leaving a considerable number of cases undiagnosed 17,18. In SSA, a region marked by high HIV prevalence and endemic HBV infection, this diagnostic limitation has major public health implications 19. Individuals who are ART-naive and co-infected with undetected OBI face elevated risks of accelerated liver disease progression, HCC, and unintentional HBV transmission 20,21. Moreover, initiating ART regimens without awareness of underlying OBI can influence treatment responses and complicate disease management 22. As emerging research continues to highlight the link between OBI and severe hepatic outcomes, understanding its prevalence in ART-naïve HIV populations across Africa has become increasingly important. Conducting a systematic review and meta-analysis will allow for a more comprehensive estimation of OBI burden, help identify diagnostic and epidemiological knowledge gaps, and provide the evidence base required to inform policy and clinical guidelines in alignment with the WHO’s global hepatitis elimination framework 23. Aim To explore the prevalence of OBI among ART treatment-naive patients in SSA. Objectives 1. To estimate the prevalence of OBI among PLWHIV naive to ART. 2. To identify the diagnostic gaps in OBI diagnosis. Review question 1. What is the prevalence of OBI among treatment-naïve HIV patients in SSA? 2. What diagnostic methods are employed in diagnosing OBI in SSA? Search strategy To write a comprehensive review and meta-analysis, MEDLINE, Web of Science, PUBMED Central, Scopus, Global Health, Embase, Porquest, Africa Wide, EBSCOHOST and CINAHL databases will be searched for research papers on OBI among treatment-naïve HIV-patients in SSA from January 2010 to December 2024 taking into consideration the prevalence of OBI in Africa among person living with HIV and the OBI diagnostic methods employed in each study. This ten (10) year search frame is chosen due to the introduction of sophisticated molecular methods in HBV diagnosis and HBV DNA extraction. The following search strategies will be employed: “Hepatitis” AND “Occult OR OBI” AND “Diagnostic methods” AND “Africa”, “HIV OR Human Immunodeficiency Virus” AND “Occult hepatitis” AND “ART-naïve” AND “Sub-Saharan Africa OR SSA”, “OBI OR Occult hepatitis B” AND “Diagnosis” AND “Treatment-naïve HIV patients OR ART-naïve HIV patient” AND “Sub Saharan Africa OR Africa” etc Inclusive and exclusive criteria All journal resources or articles extracted from the databases will be screened thoroughly to identify articles that meet the inclusive criteria. Inclusion criteria OBI in this systematic review is defined as the presence of HBV DNA less than 200IU/L in HBsAg negative individuals with or without HBcAb.  Studies among treatment-naïve HIV patients of 18 years and above will be considered.  Papers published in languages such as in English, French, Italia, Portuguese, and Arabic and have transcribed versions in English will be accepted as well. However, mix-data studies will be considered if more than 70% of the population meet the age inclusive criteria for this review.  Published abstracts that estimate HBV DNA in HBsAg negative patients irrespective of HbcAb and HBsAb presence will be included in the study.  Any study that provides evidence of OBI among a population of ART defaulters over six months will be accepted into the study.  To be consistent with the inclusive criteria set for this systematic review, much consideration will be given to any study that provides insight in understanding the prevalence of OBI among HIV patients naive to ART treatment and who are negative for HBsAg as well as studies that access the sensitivity and specificity of diagnostic methods employed in evaluating anti-HBc and HBV DNA for the diagnosis of OBI among PLWHIV. Exclusive criteria  Studies that will not define OBI as the presence of HBV DNA less than 200IU/L in HBsAg negative individuals with or without HBcAb will be excluded from the review.  Similarly, any study that includes HBV window period infections with confirmed HBsAg positivity of the study population after six months will be excluded.  Abstracts from conferences and original scripts of any study design that will aid the estimation of OBI prevalence in the target population will be excluded in the study.  Again, studies that estimate OBI prevalence from study population on nucleoside or nucleotide analogues will be excluded from the review.  Finally, journal articles that employed serological methods only and not NAT in reporting OBI presence were excluded from the study. Data Extraction and Management This review will employ Endnote 20 for intext citation, checking for duplicate references and storage of final accepted references. Covidence will be utilized in ensuring de-duplication of journal articles extracted from various databases, screening for data quality of articles accepted and for data extraction. Covidence will provide an avenue for collaboration between reviewers. Titles and abstracts will be independently screened manually by Emmanuel Salia and Evans Duah. Aminama Prince will serve as an intermediary and make the final screening decision when Emmanuel and Evans are not able to resolve a disagreement on the acceptance or rejection of a paper. Non-duplicate articles will be returned to the study pool for abstract and title screening. This process will be supported with manual checkups for reference and article duplication by the reviewers involved in this study. Duplicates identified manually during abstract and title screening of journal articles will be reported separately on the PRISMA flow diagram from those identified by the software systems applied. This will ensure that any possibility for the existence of duplication of articles and references is eliminated and reported appropriately. Data Analysis All reviewers involved in this study will assist in the extraction of data from the papers that meets the inclusion criteria. Key items of articles to be extracted will include the settings of each study, the characteristics of the study population, the sample type used in the diagnosis of OBI, the diagnostic method employed, the prevalence of anti-HBc or anti-HBs and OBI. The prevalence of OBI will be assessed based on the type of sample and serological principles each paper utilizes. By adapting the Hoy and colleagues’ tool of bias assessment