Hepatitis B, an inflammation of the liver, is caused by the hepatitis B virus, a small DNA virus with reverse transcriptase, belonging to the Hepadnaviridae family [1]. Infection with the hepatitis B virus (HBV) is a major public health problem in several regions of the world due to its frequency, complications, and socioeconomic consequences [2]. The World Health Organization (WHO) estimates that more than 2 billion people worldwide have been infected with HBV. Of these, 240 million are chronic carriers of the HBs antigen (HBsAg) [3]. In 2022, the WHO estimated that hepatitis B virus (HBV) infections caused 1.5 million deaths, most of which were attributable to complications related to chronic infections, cirrhosis, and hepatocellular carcinoma (HCC). Despite the availability of a vaccine, 296 million people were chronically infected in 2019. Africa is one of the continents most affected by this infection, with approximately 100 million people infected [4]. Sub-Saharan Africa is a highly endemic area with a prevalence of between 8% and 18% [5]. Senegal is a country where the hepatitis B virus (HBV) is endemic.

It is estimated that approximately 8% of the population is chronically infected with HBV, representing approximately 1,250,000 people [6]. According to the WHO, HBV is responsible for 80% of liver cancers, which are the most common cancers among men in Senegal [7]. Without screening and treatment, chronic HBV infection can lead to serious complications and death. Hence, the importance of good patient follow-up. The overall objective of this study is to evaluate the different serological profiles of hepatitis B obtained during screening and follow-up of patients carrying the hepatitis B virus at the Fann National University Hospital Center (CHNU).

HBV infection is a public health problem in a resource-limited country such as Senegal. This is due to its prevalence and high mortality rate from serious complications, including cirrhosis and primary liver cancer. The average age obtained in our study was 38.49 years, ranging from 2 months to 97 years. This figure is comparable to that of Mor Talla in Senegal (1645 patients) in 2021, which was 36.1 years, with extremes ranging from 0 to 86 years (Mor Talla, 2021). These results could be explained by the demographic structure of Senegal, which is characterized by a predominantly young population, thus influencing the average ages observed. The most represented age group was 30 to 40 years old (45.28%). This result is similar to that of a study conducted in Mali (1035 patients), where this age group reached 36.5% [8]. The age range obtained in these studies shows the predominance of this group in the working population, its more frequent participation in screening due to its professional and social responsibilities, as well as exposure factors such as risk behaviors, history of blood transfusions, or occupational exposure (caregivers, personnel in contact with biological fluids). In our study, outpatient patients had a prevalence of 89.45% compared to 10.55% for hospitalized patients. Among the latter, seroprevalence was characterized by a high proportion of patients from infectious and tropical disease, pulmonology, and neurology departments, with respective rates of 30.16%, 15.87%, and 15.87%. Our results are comparable to those of the study conducted in Bamako (Mali) in 2024 by Mamadou, which revealed a prevalence of 22.92% among outpatients in a sample of 505 patients. Internally, the infectious and tropical diseases department had the highest prevalence (20.83%), followed by the internal medicine department (14.58%) [9]. In addition, a study conducted in Algeria on 3,845 patients also showed that the majority came mainly from the infectious diseases department, with a prevalence of 41.50%, followed by the hemodialysis department with 32.07% [10]. Hepatitis B is frequently observed in the infectious diseases department due to its specialization in diagnosis, treatment, and follow-up. Patients with hepatitis B are often referred to or admitted to this department to receive specialized care tailored to their condition. It is therefore essential to focus hepatitis B surveillance and treatment efforts in this department in order to ensure appropriate patient care and prevent the spread of the disease. We looked for markers of chronicity in HBs antigen-positive subjects, including HBe antigen, which is a marker of active viral replication, and anti-HBe antibodies. A total of 92.56% of subjects were HBe antigen negative, and 75.11% were HBe antibody negative; of the HBe negative subjects had antibodies anti-HBe. These are markers of the cessation of viral replication. Our results differ from those of Lo et al. (n = 466), who found a seroprevalence of 24.4% for HBe antigen and 69.2% for anti-HBe antibodies in people living with HIV (PLHIV) who were HBs antigen carriers [11].This difference could be explained by the sample size and HIV-related immunosuppression, which has an impact on the immune response and viral replication markers. Regarding anti-HBs antibodies, we were able to divide our study population into two categories: those with anti-HBs antibody titers below 10 mIU/mL and those with anti-HBs antibody titers ≥ 10 mIU/mL. The threshold of 10 mIU/mL for anti-HBs antibodies is considered the threshold for protection [12]. Individuals with insufficient anti-HBs antibody titers should be vaccinated in accordance with WHO recommendations [13]. For individuals with protective levels of anti-HBs antibodies (greater than 10 IU/L), screening for anti-HBc IgG antibodies would have allowed us to distinguish those who developed immunity after resolution of the infection. In our study, we identified 174 requests for anti-HBs antibody titration in HBsAg-negative patients. Among these requests, 141 patients (81.03%) had a titer below 10 IU/L, and 33 patients had a titer above 10 IU/L, or 18.97%. In Chkouri’s study in Senegal, out of a total of 227 requests for anti-HBs antibody titration, 91 patients (40.08%) had a titer below 10 IU/L, and 136 patients had a titer above 10 IU/L, or 59.92% [14]. This difference compared to our results can be explained by a different study population, a different study period, and the patients’ varied vaccination histories. This immunity could be due to vaccination or spontaneous recovery with the production of antibodies against the virus. In our study, 411 patients presented for an anti-HBc antibody screening test, the majority of whom tested positive at a rate of 68.86%. Our results are comparable to those obtained by Mor Talla in Senegal (n = 516), who found a seroprevalence of 78.5%. These observations could be explained by the fact that Senegal is a country with a high prevalence of HBV. A large proportion of the population is exposed to the virus during their lifetime, which explains the prevalence of total anti-HBc antibodies [15]. In our study, the absence of anti-HBc IgM antibody testing is a limitation, as it would have allowed us to differentiate between acute and chronic hepatitis B infections.

Hepatitis B is a serious public health problem, and Senegal is one of the countries most affected. These observations highlight the need to strengthen awareness and vaccination campaigns, particularly among young adults and men, to promote systematic screening in high-risk services such as services for infectious diseases, and to ensure prolonged clinical follow-up in order to prevent complications.