Blood transfusion saves lives and reduces morbidity and mortality for many diseases and clinical conditions, but it is not without risk [1] . Every patient who receives a blood transfusion is at risk of contracting a post-transfusion infection such as HIV, hepatitis B virus (HBV), hepatitis C virus (HCV) or syphilitic infection, due to the shortcomings of the various national blood transfusion programmes, which often have inadequate infrastructure and limited financial resources, and sometimes have unqualified staff [2] . In 2023, according to the WHO, the prevalence of blood transfusion-related infection in low-income countries was 2.00 to 6.02% for HIV, 0.5 to 1.67% for HBV and 0.60 to 1.81% for HCV [3] .

In 2016, in a study of 599 donors in the Democratic Republic of the Congo (DRC), researchers found a prevalence of 8.01% for HBV and 2.67% for HIV [2] . In the same year, another group of researchers found an overall seroprevalence of 9.7% for HBV and 5.8% for HIV in 4458 donors [4] . Finally, a study carried out in Senegal in 2021 on 2613 donors showed that 10.5% were HBsAg positive, compared with 0.38% carrying HIV markers [5] . In a study of 8055 donors, researchers also found that 14.77% carried HBsAg, compared with 2.16% for HIV [6] . In Guinea, the first study available online, carried out in 2012 on 6401 blood donations to the Centre National de Transfusion Sanguine of Guinea (CNTS), revealed a seroprevalence of 14.94% for HBV and 1.63% for HIV [7] . An annual report from Guinea’s CNTS reported 9.02% for hepatitis B and 3.75% for HIV [8] . In the recent literature, studies of HIV and HBV marker carriage data are incomplete in Guinea. There are no studies in the N’Zérékoré region on HIV and HBV markers in blood donors. The results of this study, the aim of which was to determine the seroprevalence of HIV and hepatitis B, as well as the factors associated with seropositivity for these pathogens in blood donors received at the N’Zérékoré regional blood transfusion centre in Guinea, are thus reported.

We conducted this study to determine the seroprevalence of HIV and hepatitis B among blood donors at the N’Zérékoré Regional Blood Transfusion Centre ( Figure 2 ). The study was faced with a number of limitations, including the lack of information due to the deterioration or unavailability of certain donor registers, the illegibility of the handwriting in places (erasures, overwriting), the use of rapid diagnostic tests for the detection of serological markers, and the lack of molecular biology tests or nucleic acid detection tests which are capable of identifying infections in blood earlier and with greater sensitivity. The latter remain inaccessible and unaffordable for countries with limited resources [10] . Although they are sometimes rejected, their use is increasingly desirable, with good sensitivity, as older methods such as ELISA and Western blots have become more widely used [11] . It should be remembered that certain clinical situations, such as HIV seropositivity, can reduce the sensitivity of the rapid test [12] and also the quality of some rapid diagnostic tests, which remains to be desired and raises the issue of the use of accurate tests and safe transfusions. As for the availability of health information, this is a real problem in developing countries in general, and in Guinea in particular, because of the lack of computerisation of the system and the humidity of our landscape.

In this study, donor age ranged from 18 - 60 years, with a predominance of donors aged 25 - 34 (44.2%). Similar results have been reported by some authors in Mali, with a proportion of 40.36% of the population studied [6] . Other researchers have also reported that the 26 - 35 age group was more represented, with proportions of 57.1%, 38.4% and 36.75% respectively [13] [14] [15] . The high representation of young people in this study could be explained by the fact that they are potentially the most active and supposed to be in good health, and therefore more likely to donate blood.

Male donors were the most represented in this study (79.0%). A similar finding has been reported by other authors, in which the majority of donors were male (90.7%) [16] [17] [18] . The most represented occupational category was farmers (19.9%), followed by manual workers (19.5%). It should be remembered that agriculture is the activity practised by the majority of the Guinean population, with manual workers in second place. In the blood group determination, more than half of the donors were of blood group O (55.6%). Similar results have been reported by researchers in Gabon [19] and several other researchers in Cameroon [20] [21] [22] . In this cohort, first-time donors were more heavily represented (89.5%). This can be explained by the fact that donors are volunteers, and it is difficult to build donor loyalty. In this study, we observed a seroprevalence of 3.6% for HIV, 13.4% for HBsAg and 0.2% for HIV/HBV co-infection. In the case of HIV, this prevalence far exceeds the national figure of 1.5% according to the latest Guinea Demographic and Health Survey [23] . The prevalence of hepatitis B is similar to that reported in the literature, as Guinea is in a high-prevalence area [24] . With regard to co-infection, the proportion of 0.2% seems to be much lower than the reality in Guinea, as shown by Keita et al. [25] . In Sub-Saharan Africa, blood transfusion represents a potential risk of contamination. However, the high HIV seroprevalence in this study could be attributed partly to the performance of the system set up at the regional blood transfusion centre in N’Zérékoré (Guinea), and partly to the diagnostic tests used, which may result in false positives in the absence of confirmatory molecular biology tests. Although the study was unable to determine whether the infections were recent or chronic, it did help to improve transfusion safety, since the presence of just one of these immunoserological markers is sufficient to discard a blood bag and thus avoid contamination [11] [26] . The results of HBV screening in blood transfusion centres vary. They are 9.7% in Sierra Leone [27] , 20.4% in Burkina Faso [28] , 7.3% in Gabon [17] and 10.5% in Senegal [5] . With regard to coinfection, contrary proportions have been reported by several researchers. It was 8.49% of HBV/HIV-positive patients in Guinea [24] ; 6.47% in the Central African Republic [9] , in Mali in two studies it was 1.90% and 2.9% respectively [15] [16] . The association between HIV and hepatitis B can be explained by their modes of transmission and the risk factors associated with these infections, which are identical. The occupational category most affected was farmers (22.7%), P = 0.001). Contrary results have been reported by authors in Mali 4.13% [15] . In this study, age, serological status and history of blood donation were factors associated with HIV positivity (P < 0.05).

The study assessed the seroprevalence and associated factors of HIV and HBsAg among blood donors at the Centre Regional de la Transfusion Sanguine de N’Zérékoré (Guinea). We reported a high prevalence of HIV and HBsAg, with a predominance of men, a high representation of people from urban areas, generally farmers and with blood group O for both diseases. Almost all of the donors had never given blood. Sex, serological status and history of blood donation were factors associated with HIV positivity. For HBsAg, HIV serostatus and blood donation history were factors associated with seropositivity. Strict pre-donation screening of all donors could be a solution to ensure a good supply of quality blood for transfusion safety.

The authors would like to thank the technical staff. We would also like to thank all the participants in this study.

All the authors have contributed to the design, translation or layout of this paper, albeit to different degrees. Contributed to conception and data collection: AC, ET, INH, YY, ISD, MSD, KK and AT. Contributed to study design: AC, ET, INH, KK and AT. Contributed to data analysis: ET, INH, AT, YY, AC, JC and MC. Wrote the paper: ET, AC, INH, DK, KK, TMT, BM and SB. Correction and formatting: AC, AT, KK, MSD, BM and SB.