Project – Prevalence of Hepatitis B Virus Infection Among Prospective Blood Donors in a selected tertiary hospital in Abia State

CHAPTER ONE

INTRODUCTION

1.1 Background to the Study

Hepatitis B virus (HBV) infection remains a major global public health concern because of its ability to cause both acute and chronic liver disease. The virus primarily affects the liver and is transmitted through contact with infected blood and other infectious body fluids, including through unsafe injections, sexual contact, mother-to-child transmission, and transfusion of infected blood. Individuals with chronic HBV infection may develop serious complications such as liver cirrhosis, liver failure, and hepatocellular carcinoma. The World Health Organization (WHO, 2024) identifies hepatitis B as a significant cause of preventable illness and death worldwide, particularly in regions where access to vaccination, screening, diagnosis, and treatment remains inadequate. Consequently, identifying infected individuals and preventing the transmission of HBV through healthcare procedures are essential components of public health protection.

The global burden of hepatitis B remains substantial despite the availability of an effective vaccine and established screening procedures. According to the World Health Organization (2024), approximately 254 million people were living with chronic hepatitis B infection globally in 2022, with an estimated 1.2 million new infections occurring annually. The disease burden is particularly high in the WHO African Region, where childhood vaccination coverage and access to diagnostic and treatment services remain important challenges. Many infected individuals are unaware of their infection because HBV may remain asymptomatic for years before clinical complications become apparent. This situation makes laboratory screening particularly important in identifying infections that might otherwise remain undetected. In the context of blood transfusion, the existence of asymptomatic infections highlights the need for systematic screening of prospective blood donors before their blood is released for clinical use (WHO, 2024).

Blood transfusion is an essential component of modern healthcare because it supports the management of severe anaemia, obstetric haemorrhage, surgical emergencies, trauma, and other life-threatening conditions. However, transfusion can expose recipients to blood-borne infections when donated blood contains an infectious agent that has not been detected before transfusion. Hepatitis B virus is particularly important in transfusion medicine because it can be transmitted through infected blood, including blood collected from donors who show no obvious signs of illness. The WHO (2023) emphasises that a safe blood supply depends on a coordinated system of donor selection, testing of donated blood for transfusion-transmissible infections, quality-assured laboratory procedures, and appropriate blood handling. Therefore, determining the prevalence of HBV infection among prospective blood donors is an important step in assessing the potential risk of transfusion-transmitted hepatitis B and strengthening blood safety practices.

Prospective blood donors constitute an important population for HBV surveillance because their screening results can provide information about the occurrence of infection among individuals presenting to donate blood. These donors may include voluntary non-remunerated donors, replacement donors, and other eligible individuals who present for blood donation. Although donor selection procedures may identify some individuals with recognised risk factors, such procedures cannot independently establish whether a person is infected with HBV. Laboratory testing is therefore necessary to identify infected donors who may appear healthy. The WHO (2023) recommends that all donated blood be screened for relevant transfusion-transmissible infections, including HBV, before use. In addition, research among prospective donors can help identify differences in infection prevalence across populations and healthcare settings, thereby providing evidence to support local blood safety policies and appropriate allocation of screening resources.

Hepatitis B infection is especially relevant to sub-Saharan Africa, where transmission during childbirth and early childhood, together with exposure to infected blood and body fluids, contributes to the continuing burden of disease. The WHO Regional Office for Africa reported that nearly 65 million people were living with hepatitis B in the African Region in 2022, while the region accounted for approximately 63% of new hepatitis B infections worldwide (WHO, 2024). These figures demonstrate the importance of strengthening prevention, vaccination, testing, and surveillance across African countries. In Nigeria, the implications are particularly significant because blood transfusion services must provide safe blood for patients requiring emergency and routine medical treatment. Nnachi et al. (2022), in a study of blood transfusion services at Alex Ekwueme Federal University Teaching Hospital, Abakaliki, reported hepatitis B surface antigen seropositivity of 2.22% among screened blood donors. This finding illustrates the importance of continuing to monitor HBV infection among blood donors in Nigerian healthcare institutions.

The detection of hepatitis B virus infection among prospective blood donors depends on the use of appropriate laboratory screening procedures. Hepatitis B surface antigen (HBsAg) testing is widely used to identify individuals with current HBV infection, although a reactive result may require further assessment to establish the infection status and clinical significance. Depending on the laboratory’s resources and testing algorithm, additional investigations may include other hepatitis B serological markers and molecular tests. The WHO (2024) emphasises that accurate diagnosis, accessible testing, and linkage to appropriate care are necessary for effective hepatitis B prevention and management. For blood transfusion services, screening must be supported by quality-assured procedures, competent laboratory personnel, reliable reagents, and proper documentation of test results. Therefore, assessing HBV prevalence among prospective blood donors in a selected tertiary hospital in Abia State can provide useful information about the proportion of screened donors who test positive for HBsAg and help inform local blood safety practices.

In Abia State, tertiary hospitals play an important role in providing specialised medical care, including services that require blood transfusion for patients with severe anaemia, surgical complications, trauma, and obstetric emergencies. The safety of these transfusions depends partly on the effectiveness of the hospital’s blood donor selection and laboratory screening systems. Although national and international guidelines support screening donated blood for HBV, the prevalence of infection may vary between hospitals and populations because of differences in donor characteristics, community transmission patterns, vaccination coverage, and other epidemiological factors (WHO, 2023; Nnachi et al., 2022). Consequently, findings from another Nigerian state cannot automatically be assumed to represent the situation in a selected tertiary hospital in Abia State. A hospital-specific assessment is therefore necessary to establish the local prevalence, examine the distribution of positive results across relevant donor characteristics, and generate evidence that may support improved blood safety and infection prevention.

1.2 Statement of the Problem

Hepatitis B virus infection remains a public health challenge because infected individuals may transmit the virus without knowing their infection status. The WHO (2024) identifies the high burden of hepatitis B in the African Region and the persistent gaps in diagnosis and treatment as important barriers to controlling the disease. In blood transfusion services, these challenges are particularly concerning because individuals who appear healthy may have an HBV infection detectable only through appropriate laboratory investigations. Failure to identify infected donations before transfusion can expose recipients to a preventable infection with potentially serious long-term consequences. Therefore, establishing the prevalence of HBV infection among prospective blood donors is necessary to assess the extent of the problem within a defined hospital population.

Another problem is that blood transfusion services must balance the demand for blood with the requirement to maintain high standards of safety. Hospitals need adequate supplies of compatible blood for emergencies and routine treatment, but the urgency of clinical demand must not compromise the screening of donated blood. Nnachi et al. (2022) found that HBV was the most prevalent of the transfusion-transmissible infections examined in their study of a tertiary hospital in southeastern Nigeria, with a reported seroprevalence of 2.22%. Although this finding provides useful evidence, it does not establish the current prevalence among prospective blood donors in the selected tertiary hospital in Abia State. Differences in geographical setting, donor composition, screening practices, and study period mean that local investigation is necessary rather than relying exclusively on findings from other institutions.

Furthermore, the prevalence of HBV infection among prospective blood donors may differ according to age, sex, and other demographic characteristics. Understanding these patterns may help researchers and healthcare professionals identify groups in which positive screening results occur more frequently and improve the interpretation of local epidemiological data. However, such differences should be established through systematic data collection and statistical analysis rather than assumptions. The WHO (2012) recommends structured donor selection procedures to protect both blood recipients and donors, while the WHO (2023) emphasises the importance of screening donated blood for transfusion-transmissible infections. Without hospital-specific evidence on prevalence and the distribution of positive results, it may be difficult to determine the extent to which the infection represents a concern among prospective donors in the selected facility.

The central problem, therefore, is the need for reliable, location-specific evidence on hepatitis B virus infection among prospective blood donors in a selected tertiary hospital in Abia State. Although existing research demonstrates that HBV infection occurs among blood donors in Nigeria, the findings from other hospitals cannot substitute for data collected from the selected study location. A systematic assessment is needed to determine the proportion of prospective blood donors who test positive for HBsAg and to examine whether infection prevalence differs across selected demographic characteristics. The findings may provide a basis for strengthening donor screening, health education, counselling, and referral for further assessment where indicated. This study is consequently designed to determine the prevalence of hepatitis B virus infection among prospective blood donors in a selected tertiary hospital in Abia State.

1.3 Aim and Objectives of the Study

1.3.1 Aim of the Study

The aim of this study is to determine the prevalence of hepatitis B virus infection among prospective blood donors in a selected tertiary hospital in Abia State.

1.3.2 Specific Objectives

The specific objectives are to:

1. Determine the prevalence of hepatitis B virus infection among prospective blood donors in the selected tertiary hospital in Abia State.

2. Determine the distribution of hepatitis B virus infection among prospective blood donors according to age.

3. Assess the distribution of hepatitis B virus infection among prospective blood donors according to sex.

4. Examine the association between selected demographic characteristics and hepatitis B virus infection among prospective blood donors in the selected tertiary hospital.

1.4 Research Questions

The following research questions will guide the study:

1. What is the prevalence of hepatitis B virus infection among prospective blood donors in the selected tertiary hospital in Abia State?

2. How is hepatitis B virus infection distributed among prospective blood donors across different age groups?

3. How is hepatitis B virus infection distributed between male and female prospective blood donors?

4. Is there a significant association between selected demographic characteristics and hepatitis B virus infection among prospective blood donors in the selected tertiary hospital?

1.5 Research Hypothesis

The following null hypothesis will be tested at the 0.05 level of significance.

H₀: There is no statistically significant association between selected demographic characteristics (age and sex) and hepatitis B virus infection among prospective blood donors in the selected tertiary hospital in Abia State.

1.6 Significance of the Study

The findings of this study may be beneficial to the following groups:

Hospital management: The findings may provide information about the prevalence of HBV infection among prospective blood donors and support decisions concerning blood safety procedures, laboratory resources, and infection prevention policies.

Medical laboratory scientists: The study may contribute to knowledge of HBV screening among prospective blood donors and reinforce the importance of quality assurance, accurate test interpretation, and appropriate documentation of laboratory findings.

Blood transfusion services: The findings may help identify the local burden of HBsAg positivity and support continuous monitoring of transfusion-transmissible infections among prospective donors.

Public health authorities: The results may provide local epidemiological information that can support hepatitis B prevention programmes, vaccination awareness, testing initiatives, and health education.

Prospective blood donors: The study may encourage awareness of hepatitis B, the importance of appropriate testing, and the need for individuals with reactive screening results to receive counselling and further clinical assessment.

Researchers and students: The study may serve as a reference for future investigations on HBV prevalence, blood safety, donor characteristics, and transfusion-transmissible infections in Abia State and other parts of Nigeria.

1.7 Scope of the Study

The study will focus on the prevalence of hepatitis B virus infection among prospective blood donors in a selected tertiary hospital in Abia State, Nigeria. It will cover prospective donors who present for blood donation and meet the study’s eligibility criteria during the specified data collection period. The investigation will determine the proportion of donors who test positive for hepatitis B surface antigen and examine the distribution of positive results according to age and sex. It will also assess the association between selected demographic characteristics and HBV infection. The study will not be intended to estimate the prevalence of HBV in the entire population of Abia State, nor will HBsAg screening alone establish the full clinical status or duration of infection in a reactive donor.

1.8 Operational Definition of Terms

Hepatitis B virus (HBV): A virus that infects the liver and can cause acute or chronic hepatitis.

Hepatitis B virus infection: Infection with HBV, assessed in this study through the specified laboratory screening procedure, principally HBsAg testing.

Prevalence: The proportion of prospective blood donors who test positive for HBV infection according to the study’s laboratory definition during the study period.

Prospective blood donor: An individual who presents to the selected tertiary hospital for blood donation and is assessed for eligibility to donate.

Blood donor screening: The laboratory testing and donor assessment procedures used to identify infections or other conditions relevant to the safety of donated blood.

Hepatitis B surface antigen (HBsAg): A viral surface protein used as a marker of current HBV infection when detected through an appropriate diagnostic test.

Tertiary hospital: A healthcare institution that provides specialised medical services, including advanced diagnostic and treatment services, and may serve as a referral centre.

Transfusion-transmissible infection: An infection that can be transmitted to a recipient through transfusion of contaminated blood or blood components.

Seropositivity: The detection of a specified infection marker in a person’s blood sample using the relevant laboratory test.

Project – Prevalence of Hepatitis B Virus Infection Among Prospective Blood Donors in a selected tertiary hospital in Abia State