Hidden dangers-prevalence of blood borne pathogens, hepatitis B, C, HIV and syphilis, among blood donors in Sierra Leone in 2016: opportunities for improvement: a retrospective, cross-sectional study

Introduction Transmissible blood-borne infections are a serious threat to blood transfusion safety in West African countries; and yet blood remains a key therapeutic product in the clinical management of patients. Sierra Leone screens blood donors for blood-borne infections but has not implemented prevention of mother-to-child transmission for hepatitis B. This study aimed to describe the overall prevalence of hepatitis B and C, HIV and syphilis among blood donors in Sierra Leone in 2016 and to compare the differences between volunteer versus family replacement donors, as well as urban versus rural donors. Methods Retrospective, cross-sectional study from January-December 2016 in five blood bank laboratories across the country. Routinely-collected programme data were analyzed; blood donors were tested with rapid diagnostic tests-HBsAg for HBV, anti-HCV antibody for HCV, antibodies HIV1&2 for HIV and TPHA for syphilis. Results There were 16807 blood samples analysed, with 80% from males; 2285 (13.6%) tested positive for at least one of the four pathogens. Overall prevalence was: 9.7% hepatitis B; 1.0% hepatitis C; 2.8% HIV; 0.8% syphilis. Prevalence was higher among samples from rural blood banks, the difference most marked for hepatitis C. The proportion of voluntary donors was 12%. Family replacement donors had a higher prevalence of hepatitis B, C and HIV than volunteers. Conclusion A high prevalence of blood-borne pathogens, particularly hepatitis B, was revealed in Sierra Leone blood donors. The study suggests the country should implement the prevention of mother-to-child transmission of hepatitis B and push to recruit more volunteer, non-remunerated blood donors.


Introduction
Blood transfusions save lives and improve health but in low income countries, particularly in Africa, many patients requiring blood are faced with two crucial blood transfusion-related issues--blood shortages and unsafe blood [1]. In the World Health Organization respectively [2,3]. This is very low compared to high-income countries whose mean donation rate is 36.4 donations per 1000 population with a range from 13.3-64.6 [4]. Many studies have shown a high prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV) and syphilis among blood donors in West African countries [5][6][7][8][9][10]. These infectious agents are serious threats to blood safety for the recipients and pose a public health problem. In 2001, the WHO African region adopted a strategy (document AFR/RC51/9) that aimed at improving blood transfusion safety and bridging the gap between blood needs and blood availability in health services. Its objectives were to recruit more low-risk donors to improve the safety of blood and blood products and to promote their appropriate use by clinicians. The strategy had defined targets: 100% of blood units transfused were to be screened for HIV and other blood-borne infections; and at least 80% of all donations were to be by volunteer, non-renumerated blood donors (VNRBD) [11]. In  However, Sierra Leone did screen donors for all the recommended pathogens, including HBV, HCV, HIV and syphilis. Blood remains a key therapeutic product in the clinical management of maternity and paediatric patients in Sierra Leone but often the demand is greater than the supply. The demand seems to be greater in the rural areas where malaria prevalence is higher and there are delays for referral of both maternal and paediatric cases from peripheral health units.
There are three types of blood donors in Sierra Leone-VNRBD, family replacement donors (FRD) and paid donors. VNRBD provide their blood for free and usually on a regular basis. FRD are sought when a patient requires a transfusion yet there is inadequate or no blood in the bank. When these two sources fail, paid donors offer theirs for a negotiable fee. Studies of blood-borne pathogens in blood donors are limited in Sierra Leone. One was conducted in a small private mission hospital in northern Sierra Leone, which showed a high prevalence of HBV, HCV and HIV [12]. Similarly, studies have been conducted among patient sub-groups (pregnant women and general medical patients) that have shown high prevalence especially for HBV [13][14][15]. Despite the high prevalence of HBV reported in these studies, Sierra Leone has yet to implement the 24-48 hour post-delivery administration of hepatitis B vaccination plus hepatitis B immunoglobulin to babies born to HBsAg positive mothers, a strategy that has immensely reduced HBV infection elsewhere [16]. The country, however, does have hepatitis B as part of its vaccination schedule for under-five children starting from six weeks after birth. Reports show that VNRBD are the safest group of donors, as the prevalence of blood-borne infections is lowest among this group [9,17]. However, a study in Kiribati reported that both voluntary and family replacement donors had similar positive viral and/or bacterial serological test results [18]. It is unclear in Sierra Leone if differences exist in the prevalence of these infections between VNRBD and FRD, as well as urban and rural blood donors, aspects of blood donation safety that have not been explored. Thirty studies conducted in Ghana reported a higher prevalence of HBV in rural than urban settings [19]. This study thus aimed to describe the overall prevalence of the blood-borne infections (HBV, HCV, HIV and syphilis) among blood donors in selected regions in Sierra Leone in 2016 and to compare differences between VNRBD versus FRD and those in urban versus rural donors.

Methods
Design: This was a retrospective, cross-sectional study conducted between June and August 2017.
General setting Sierra Leone is located in West Africa and has a population of 7.1 million, of whom 79% live in rural areas [20]. It borders on the Atlantic Ocean to the west, Guinea to the north and east, and Liberia to the south. The already weak and crippled health care system following the eleven year civil war (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)  Comparisons between different categorical groups used the Chisquare test and presented in odds ratios (95% confidence interval).
Level of significance was set at <5%.

Ethics approval: The Sierra Leone Ethics and Scientific Review
Committee granted approval to conduct the study. Similarly, the National Blood Bank Services and respective hospital in-charges granted their permission for the study. The study maintained confidentiality of data and subjects throughout. The study did not need to obtain informed consent from donors as the study was a

Results
There were 16865 blood donors whose samples were tested at the five blood banks; 58 samples had missing results for all the four pathogens (HBV, HCV, HIV and syphilis) and therefore could not be included in the analysis; hence 16807 samples were analyzed. Table   1 shows their demographic characteristics with most being males (80%) and from the age range of 18-38 years. Of the donors, 2285 (13.6%) tested positive for at least one of the four pathogens.
Finally, Table 4 shows the differences in prevalence of the bloodborne diseases among family replacement and volunteer donors.

Discussion
This is the largest study on the prevalence of transmissible bloodborne pathogens among blood donors in Sierra Leone; and probably the first study that investigated the differences in prevalence among VNRBD and FRD as well as urban versus rural blood donors. This study found the following levels of prevalence: HBV, 9.7%, was higher compared to studies in Ivory Coast, Ghana and Cameroon 9.7% and 10.0% respectively [2,3]. When compared to other African countries, Sierra Leone (at 12%) ranked as 3 rd lowest in Africa and the least in West Africa in the 2013 report [3].
Most importantly, the figure further indicates that Sierra Leone is far below the target (at least 80%) set by WHO [11]. FRD recorded slightly higher prevalence in all pathogens except for syphilis; this is consistent with previous studies conducted in Duala, Cameroon 2014 and Egypt 2014 [9,17]. However, this is in contrast to the study in Kiribati which reported that there was no difference between the two types of donors with regards to blood-borne infections [18]. The higher prevalence among FRD in general could be associated with the fact that VNRBD are recruited, monitored and followed up by the Sierra Leone Red Cross, unlike FRD who are recruited on an ad hoc basis from family members or paid donors.
Unfortunately, since paid donors were included among the group of FRD, we could not differentiate between these two groups. Analysis of purely paid donors may have shown an even higher prevalence. . The prevalence of all pathogens was slightly higher among rural blood donors compared to urban ones, which is in agreement with the studies in Ghana [19]. The reasons for this could be associated with two key factors-access to medical care, including diagnostics, is more limited in rural communities compared to urban ones in Sierra Leone. Secondly, the literacy level in rural areas, described as the percentage of the population that has never attended school (32.7%) is almost three times higher than in the urban areas (11.5%) [22]; this could make it more difficult for rural communities to understand health messages regarding transmission routes of diseases including blood-borne infections. Further studies aimed at determining the epidemiology of blood-borne infections among the general population will be of value in determining the population prevalence. Some of the key strengths of this study are: there was a large sample size and it covered all five regions in the country. Test kits, the method of testing samples, recording of information and data collection were standardized across all the laboratories. It also followed the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines as highlighted in the British Medical Journal (BMJ) 2007 [24]. However, the study had some limitations: it relied on routine programme data collected by the laboratory staff and therefore could not control for data quality at the data collection stage; commercial or paid donors could not be separated because they were not uniquely labelled; the registers did not specify whether the volunteer blood donors were first, second or subsequent blood donations; and the results from this study cannot necessarily be representative of the country as only five blood bank laboratories were studied.

Conclusion
This study found a high prevalence of blood-borne pathogens among blood donors in five blood bank laboratories in urban and rural Sierra Leone; hepatitis B virus infection was most common. There are also a number of operational implications from this study.
First, with almost 14% of all donations having at least one pathogen, there was a significant percentage of blood being unsuitable for donation. This is a loss in a context of stretched blood resources. All efforts to reduce these diseases will benefit the blood supply. Second, although the prevalence of pathogens was higher among family replacement blood donors, the positivity rate of test results among volunteer donors, the group WHO has confirmed the safest blood donors, was concerning and therefore suggests that the recruitment criteria to be re-examined and where necessary modified to promote safer blood donations. Third, with HBV prevalence most common in Sierra Leone, it is paramount that the country implement the prevention of mother-child-transmission, a programme that has been so successful elsewhere [16]. Finally, there should be some way to link positive blood donors of HBV, HCV and syphilis to care services if at all possible.
What is known about this topic  One study in Sierra Leone using blood donors in a rural hospital which showed a high prevalence of blood-borne diseases;  Two studies in patients seeking general healthcare services in hospital and showed a high prevalence of blood-diseases;  Another study in pregnant women in an urban hospital found the prevalence of hepatitis B virus infection at 6.2%.

What this study adds
 The prevalence of blood-borne infections could be higher in rural than urban settings;  Although the prevalence of blood-borne infections is lower among volunteer/non-remunerated blood donors, family replacement donors (including paid donors) were used much more commonly;  Given the high prevalence of hepatitis B, starting a neonatal immunization programme in Sierra Leone would be worthwhile.