Objective: The objective of this study is to identify, in addition to the factors already known, other risk factors for hepatitis B in the Central African context and more particularly in donors. Methods: This is a case-control study carried out among regular blood donors in the city of Bangui, capital of the Central African Republic and Bimbo, a neighboring town. The study population consisted of regular donors who tested positive for hepatitis B or cases and donors who tested negative or controls. Three witnesses were chosen for a case. The sample resulting from an empirical survey consisted of 245 cases and 735 controls. The selected witness was from the same district and had the same sex and an age close to that of the case. The data collected by interview were entered and analyzed with Epi Info 7. Risk ratio (RR), adjusted RR and Khi2 test significant for p ˂5% served as a statistical test. Results: A total of 980 regular blood donors aged 18 to 53 years were interviewed, of whom 960 (97.95%) were male. Unprotected sex (RRa=10.5), multi-partner sexual (RRa=2.79), reuse of hairdressing equipment (RRa=6), touching (RRa=5), flute (RRa=4.36), storytelling (RRa=3.75), single status and low level of education were significantly associated with the occurrence of hepatitis B (p˂0.05). The non-exchange of purging material (RRa=0.97) and cigarette material (RRa=0.92) ensured a significant protective effect against hepatitis B. Conclusion: This study confirms the risk factors already known and has made it possible to identify other risk factors of the in the Central African context such as touching, flutes, reuse of hairdressing equipment and the notion of storytelling.

Background: Incidence, one of the most commonly used indicators of morbidity in epidemiology, measures the number of new cases of a disease over a period of time. Previous studies of hepatitis B in the Central African Republic are much more concerned with prevalence. Also, the residual risk of transmission of the disease by transfusion is not yet known. The aim of this study was to study the evolution of hepatitis B incidence among regular blood donors in the cities of Bangui and Bimbo in Central Africa and to estimate the residual risk of viral transmission during blood donations. Methods: This is a retrospective study conducted at the National Blood Transfusion Centre in Bangui, covering data from 2015 to 2019. The sample consisted of regular DBS (two or more blood donations) living in the cities of Bangui and Bimbo. The Monolisa immuno-enzymatic test was used for the search for the HBs antigen. The data collected was captured and analyzed with Epi Info 7. The average incidence rate was achieved by dividing the total annual rates by five. The exact Khi2 or Fisher test at the 5% threshold compared the proportions. Search authorization No 574/MSP/DIR. CAB/DR/SGRHF/ 2017 enabled the study to be carried out. Results: From 2015 to 2019, 19762 regular volunteer donors were monitored. These donors were between the ages of 18 and 64 (average age of 28 years) with a male predominance (n -95%). The number of donations ranges from 2 to 105. The incidence rate of hepatitis B was 47.87 degrees (240/5013) in 2015, 63.06 degrees (253/4012) in 2016, 75.33 (307/4075) in 2017, 100.56 (320/3182) in 2018 and 108.04 (376/3480) in 2019. The average incidence rate was 78.97 degrees. The incidence rate was significantly higher among donors aged 25 to 34, men, donors who made less donation (2 to 19 donations) and In Bangui. The estimated average residual risk of viral transmission was 6.02 per 1000 blood donations. Conclusion: The incidence of hepatitis among regular volunteer donors has increased steadily from year to year. Younger age, males, regular donors who made less donations and the city of Bangui were more affected. The presence of co-infection with HIV and syphilis suggests sexual transmission of hepatitis B. Advocacy for free vaccination of regular donors and the introduction of genomic testing will reduce the residual risk.