A descriptive and analytical cross-sectional study was carried out from 23 to 25 September 2022 in the Kara region in northern Togo, 420 km from Lomé, the capital of Togo.

The study population consisted of women of childbearing age in the Kara region. The eligibility criteria included: 1) being between the ages of 18 and 45, 2) having resided in the Kara region in the 12 months leading up to the survey, and 3) providing oral consent for enrollment in the study.

Given the context of a fairground campaign, an accidental non-probability sampling method was used to recruit the women.

The number of subjects required was calculated on the basis of estimates of the prevalence of HBsAg infection among women in Togo, estimated at 10% [15] . For this estimate to be accurate to 1%, i.e., a 95% confidence interval for HBsAg prevalence of between 8% and 12%, at least 384 subjects would need to be included.

The data was collected using a standardised questionnaire. The questionnaire was developed by an epidemiologist and a biologist and administered face-to-face by nurses who had been trained beforehand.

The average time taken to complete the questionnaire was five minutes. The questionnaire included items on socio-demographic characteristics, sexuality, gynaeco-obstetric history and condom use.

The questionnaire was pre-tested with 10 women to reformulate questions that were difficult to understand. The women who took part in the pre-test did not take part in the final survey.

A fairground campaign was organised by the Kara Regional Health Department. A space was set up to welcome the participants and to carry out the hepatitis B counselling and screening activities effectively. Only volunteers were enrolled in the study.

On-site screening for hepatitis B was carried out by laboratory technicians who had been trained beforehand. Capillary blood samples were taken from the fingertips and tested using the “SD-BIOLINE HBsAg WB” rapid immunochromatographic tests. Pre- and post-test advice on the hepatitis B virus was given, and the serological status was communicated to the participants 2 to 3 hours after the sample was taken. Once the results were available, the healthcare professionals explained the results to the participants. In the event of a positive result, appropriate medical advice was provided, and those concerned were referred to healthcare facilities for full medical follow-up and treatment if necessary. In the event of a negative result, participants were urged to take preventive measures such as vaccination (after additional tests had been carried out, including hepatitis B markers) and the use of safe sex practices to avoid future exposure to the hepatitis B virus.

After collection, the data was entered and saved on a database developed using EPIData (French version 3.1). The data were analysed using R © version 4.2.1 software. Quantitative variables were presented as medians with their interquartile ranges (IQR), and categorical variables were presented as numbers and proportions. The prevalence of hepatitis B was estimated with its 95% confidence interval. Univariate and multivariate logistic regression analyses were performed to identify factors associated with HBV infection. The significance threshold for statistical tests was set at 5%.

This study received favourable opinions from the Bioethics Committee for Health Research (opinion number 02/2022/CBRS dated 18 January 2022) and from the Regional Director of Health in Kara. The objectives of the study were explained to the participants. They were informed that their participation was voluntary and that they were free, without justification, to withdraw at any time without any negative consequences for them. They were given the necessary time to reflect before deciding whether or not to take part in the study. Verbal consent was obtained from each participant prior to inclusion. The confidentiality of the data collected was guaranteed by using a unique identifier.

A total of 327 women with a median age of 34 years, IIQ [25 - 43] were enrolled. The majority (89.0%) were married and only 19.3% had a university education. The socio-demographic characteristics of the participants are summarised in Table 1.

Almost half (49.5%) of the women had had their first sexual intercourse before the age of 18 and 2.1% had had 2 or more sexual partners at the time of the survey.

The majority (91.7%) had not used a condom the last time they had sex.

Table 2 describes sexuality. Participants’ obstetric history and condom use at last intercourse.

The prevalence of hepatitis B was 10.4% (95% CI: [7.5 - 14.2]).

In multivariable analysis, having had sexual intercourse for the first time after the age of 18 (ORa = 0.17; 95% CI [0.06 - 0.43]; p < 0.001) and a secondary (ORa = 0.24; 95% CI [0.09 - 0.61]; p = 0.003) or university (ORa = 0.25; 95% CI [0.77 - 0.86]; p = 0.028) level of education were protective factors against HBV infection.

The factors associated with viral hepatitis B infection are summarised in Table 3.