Serological Status of Viral Hepatitis B and Associated Factors Among Sex Workers in Douala (Littoral-Cameroon)

Serological Status of Viral Hepatitis B and Associated Factors Among Sex Workers in Douala (Littoral-Cameroon


Introduction
Viral Hepatitis B (VHB) is a real concern for international organisations in general and the Cameroonian authorities in particular [1].It is a potentially fatal hepatic infection caused by the hepatitis B virus (HBV), contagious with humans as the only reservoir [2].The virus is classified as a Hepadnaviridae, with a circular, partially double-stranded, small DNA [3].Transmission of the disease occurs mainly through unprotected sex or contact with infected biological (Littoral-Cameroon) materials [2,3].According to the World Health Organisation (WHO), 296 million people worldwide are estimated to be living with chronic HBV, and the annual number of HBVrelated deaths is estimated to be more than 780,000 due to cirrhosis or liver cancer [4].In 2019, it is estimated to have caused almost 290,000 deaths worldwide [4,5].Furthermore, sub-Saharan Africa is an area of high HBV prevalence with a chronic carriage rate of over 8%, compared to less than 1% in Western Europe and North America [6].In Cameroon, the prevalence is 11.2%, making it one of the highest in Africa [7].However, in many countries, female sex workers (FSWs) are considered a high risk group for sexually transmitted infections.Studies by Zoumana et al, in Mali, and Ouedraogo et al, in Burkina Faso, on HBV carriage among FSWs found prevalences of 2.7% and 12.8% respectively [2,7].Furthermore, studies on HBV among SWs have not yet been conducted in the Cameroonian context, hence our objective to determine the serological status of HBV and associated factors among SWs in the city of Douala.

Method
Type of study and study population: We conducted a descriptive cross-sectional study among consenting sex workers living in the city of Douala.The study was carried out over a period of two months, from 1 August to 2 October 2022, in five districts of the city of Douala, namely: Douala 1 er , Douala 2 ème , Douala 3 ème , Douala 4 ème and Douala 5 ème .The recruitment of the latter was done consecutively.
Data collection tools and procedure: Data collection was carried out in prostitution venues (street and brothels) by direct interview using a questionnaire which collected sociodemographic data (age, sex, level of education, marital status), medical history (history of sexually transmitted diseases, use of antivirals) and data related to the profession of sex worker (years of experience, frequency of work, number of clients per day, use of contraceptives, history of STDs, use of sharp objects).
Selection criteria for the study population: The study population included HCV patients living in the city of Douala who gave free and informed consent.Participants on antivirals were excluded from the study.
Collection and laboratory analysis of blood samples: The conditions for proper collection were observed throughout the study.To obtain serum, we used collection tubes without anticoagulant (dry tubes).Each tube was coded and the collected specimens were centrifuged at room temperature at 3000 rpm for 03 minutes.The serum obtained was transferred to cryotubes previously labelled with the same starting code, then stored at a temperature between 2°c and 8°c pending further analysis.
Data analysis: Data were entered into CSPRO version 18.0 and exported to IBM SPSS statistics version 26 for analysis.Logistic regression analysis was performed to determine the degree of association of HBsAg carriage, with a significance level of 5%.
Ethical considerations: an ethical clearance was issued to us by the Institutional Ethics Committee of the University of the Mountains (CIE-UdM), under the reference N°2022/187/UDM/PR/CEAQ; then we also obtained an administrative research authorization issued by the Regional Delegate of Public Health of the Littoral Region under the N° 0347/AAR/MIINSANTE/DRSPL/BCASS; and finally we received a research authorisation under reference N° 2022/0888/L/HGOPED/DG/DRFI from the Director of the Gynaecological-Obstetric and Paediatric Hospital of Douala for the analysis of our specimens in the microbiology laboratory of his structure.

Discussion
The HBsAg was found exclusively in adult and unmarried participants, but was also present in the majority of sex workers with secondary school education who were based in the Douala 5 district ème ; in fact, the length of time in the profession, the high number of adult sex workers, and the lack of condom use could explain the exclusive presence of HBsAg in adult and unmarried participants.In addition, insufficient information and low general knowledge about viral hepatitis B could explain the presence of HBsAg in sex workers who had secondary school education [8].
Analysis of our data revealed an HBsAg prevalence of 10% (7/87), which is higher than the prevalence obtained by Doumbia et al in 2021 among female sex workers (2.7%) in the Kenieba mining area of Mali; and lower than that obtained by Ouedraogo et al in 2019, who obtained a crude prevalence of 12.8% among female sex workers in three cities of Burkina Faso [2,7].These fluctuations in prevalence could be explained by the different sample sizes in each study.In addition, as viral hepatitis B is a sexually transmitted infection, the presence of HBsAg in these sex workers could be associated with lack of condom use.
The prevalence of HBeAg in the present study is estimated at 1% (1/87), a result that is at odds with those obtained by Doumbia et al [2], whose HBeAg test was negative in female sex workers; however, Katilé et al [9] recorded a prevalence of 7.4% of HBeAg-positive persons in a study carried out in the regional hospital of Kayes.HBeAg positivity would increase the risk of virus spread within the population, this risk has been estimated at more than 90% if HBeAg is detected in serum [10,11].However, even in the absence of HBeAg, the risk of HBV transmission exists and the interpretation of the absence of HBeAg must take into account the possibility of viral replication in asymptomatic carriers and in the case of viral mutation of the C gene, in which case high levels of viremia are possible [12,13].
The prevalence of AcHbs, AcHbe and AcHbc in the present work was 33%; 23% and 33% respectively.These rates are high compared to those obtained by Zayet et al [14] who worked on 229 health workers with a positivity rate of 15.3%; 7.34%; 22.94% for AcHbs, AcHbe and AcHbc respectively.This difference could be explained by the lack of knowledge and awareness among sex workers about viral hepatitis B and preventive measures such as vaccination and condom use.
Univariate logistic regression analysis showed that the primary (OR= 0.042; 95% CI = 0.002-0.973;P=0.048) and secondary (OR= 0.034; 95% CI = 0.003-0.459;P=0.011) education level of participants was significantly associated with HBsAg carriage.This could be explained on the one hand by an insufficient level of information and on the other hand by the lack of implementation of the national plan to combat viral hepatitis B following the example of the national plan to combat HIV/AIDS and COVID-19.Emphasis should be placed on different sources of information such as the media and social networks, followed by awareness-raising in schools and at prostitution sites in this case.Establish vaccination coverage and free vaccines for adults.
Certain limitations were identified in the present work, namely, the small size of our sample linked to the reluctance of sex workers; the lack of use of more sensitive diagnostic tests such as Elisa or PCR (viral load) leading to an underestimation of the prevalence of HBsAg; and the quantitative crosssectional nature of the present work did not allow for causal associations to be found as would be the case in a case control study.Indeed, the latter has a more thorough level of evidence of causality than cross-sectional studies.

Conclusion
The present work shows that a variety of serological profiles of viral hepatitis B were found among female sex workers in the city of Douala, namely: infected (7/87); vaccinated (17/87); contact with the virus (11/87); not infected (46/87), former infection (6/87).In addition, primary and secondary education, as well as barmaid and shopkeeper occupation were significantly associated with HBsAg carriage.The implementation of large-scale awareness campaigns (via the media, social networks, and within schools) and expanded vaccination programmes against HBV throughout the country would help to reduce its prevalence.

Figure 1 .
Figure 1.Serological profiles of viral hepatitis B.

Table 1 .
General characteristics of the population according to HBsAg carriage.
Adolescent: 15 to 19 years; adult: 20 years and over Table

Table 2 .
Socio-demographic factors associated with HBsAg carriage.

Table 3 .
Occupational characteristics of sex workers associated with HBsAg carriage.