Évaluation du risque infectieux résiduel chez les donneurs de sang au Centre national de transfusion sanguine de Conakry

Prevalence of HIV and Viral Hepatitis Markers among Healthcare Workers in the Republic of Guinea

Healthcare workers are much more likely to be infected with HIV and hepatitis viruses compared to the general population. Although healthcare workers are more aware of HIV and hepatitis viruses, several countries in Africa lack a comprehensive grasp of disease routes and transmission risks. The aim of this study was to assess the prevalence of the serological and molecular biological markers of HIV and viral hepatitis among healthcare workers in the Republic of Guinea. The study material was 74 blood serum samples collected from healthcare workers who received additional training at the Institute of Applied Biological Research of Guinea (IRBAG, Kindia, Republic of Guinea). The markers examined included HBsAg, HBeAg, anti-HBs IgG, anti-HBcore IgG, anti-HCV qualitative determination, anti-HEV IgM and IgG, anti-HAV IgM and IgG, and anti-HIV. For viral DNA and RNA detection, nucleic acids were extracted from blood serum, and viral presence was inferred using real-time PCR with hybridization fluorescence detection. A high prevalence of viral hepatitis B markers was shown, and significantly fewer cases of viral hepatitis C and HIV were detected. Almost all examined medical workers had anti-HAV IgG antibodies, but no antibodies to hepatitis E virus. Apparently, the identified markers depend on the general prevalence of certain pathogens in the region and are associated with the traditions and characteristics of the country's residents.

[Prevalence of viral hepatitis B markers among blood donors in the Republic of Guinea]

INTRODUCTION

The problem of transfusion safety in relation to parenteral viral hepatitis still remains relevant. Viral hepatitis B (HB) remains the most common viral infection transmitted through transfusion procedures. One of the natural phases of chronic hepatitis B (CHB) is occult hepatitis B infection (OBI), characterized by an undetectable HBsAg (regardless of the other serological markers content) in the presence of hepatitis B virus (HBV) DNA in the liver tissue and an extremely low, up to undetectable, level of viral load in the blood. In the Republic of Guinea, as in most countries on the continent, the prevention of HBV transmission through transfusion is still based on HBsAg serological testing of donors only. In this connection, OBI remains as a potential threat to blood transfusion safety. Detection of HBV DNA is a reliable preventive measure against transmission of the virus from donors with HBsAg-negative HBV infection, especially in highly endemic regions. In this regard, the study was conducted to substantiate recommendations for improving blood safety against the background of significant HBV prevalence in the Republic of Guinea.The aim of the work was the evaluation of serological and molecular markers of HBV infection in blood donors in the Republic of Guinea.

MATERIAL AND METHODS

We examined 250 blood samples obtained from donors living in Conakry, Republic of Guinea. Samples were tested for the presence of serological (surface antigen, HBsAg; antibodies (ABs) to surface (anti-HBs IgG) and core (anti-HBc IgG) antigens) and molecular (DNA) markers of HBV infection.

RESULTS AND DISCUSSION

The overall detection rate of hepatitis B markers was 83.2%; HBsAg was detected in 16.4% of all individuals. The high incidence of HBsAg in men (19.55%) compared to women (8.45%) was shown, the relative risk of HBV infection with the formation of HBsAg-positive chronic hepatitis B in males was also significantly higher. The prevalence of the HBV DNA in the study group was 30.4%, the OBI cases accounted for 15.6%. The prevalence of this form of the disease was shown in donors aged 30-49 years (24.78%), in the group of people younger than 30 years, the incidence was lower (8.73%), and at the age of over 50 years, OBI was not detected. Based on the phylogenetic analysis of 76 virus isolates, it was shown that genotype E prevails in the examined group (85.53%).Cases of pathogen DNA detection occurred in HBsAg-negative blood donors in the presence of anti-HBs IgG (n = 4), as well as in the simultaneous presence of ABs anti-HBs IgG and anti-HBc IgG (n = 7). The viral load exceeded 200 IU/ml in OBI samples. Escape mutations were detected by sequencing in each OBI sample, contributing to the virus escaping from diagnostic based on screening for HBsAg.

CONCLUSION

Assessment of the prevalence viral hepatitis B markers in blood donors, determination of genotypes and clinically significant mutations of virus variants are necessary to ensure safe medical manipulations, control and prevention of the spread of this infectious agent.

Hepatitis B virus infection and its associated factors among medical waste collectors at public health facilities in eastern Ethiopia: a facility-based cross-sectional study

BACKGROUND

The risk of hepatitis B virus infection among medical waste handlers who undergo collection, transportation, and disposal of medical wastes in the health institutions is higher due to frequent exposure to contaminated blood and other body fluids. There is limited evidence on the seroprevalence of hepatitis B among medical waste handlers in eastern Ethiopia. The study was aimed at studying the seroprevalence of Hepatitis B Virus and associated risk factors among medical waste collectors at health facilities of eastern Ethiopia.

METHODS

A facility-based cross-sectional study was conducted among randomly selected medical waste collectors from public health facilities in eastern Ethiopia from March to June 2018. A pre-tested and well-structured questionnaire was used to collect data on socio-demographic characteristics and hepatitis B infection risk factors. A2.5ml venous blood was also collected, centrifuged and the serum was analyzed for hepatitis B surface antigen using the instant hepatitis B surface antigen kit. Descriptive summary measures were done. Chi-square and Fisher exact tests were used to assess the risk of association. Multivariate logistic regression was conducted with 95% CI and all value at P-value < 0.05 was declared statistically significant.

RESULTS

From a total of 260 (97.38%) medical waste collectors participated, HBV was detected in 53 (20.4%) of the participants [95%CI; 15.8, 25.6]. No significant differences were observed in the detection rates of HBV with respect to socio-demographic characteristics. In both bivariate and multivariable logistic regression analysis, being unvaccinated (AOR = 6.35; 95%CI = [2.53-15.96], P = 0.001), history of blood transfusion (receiving) (AOR; 3.54; 95%CI; [1.02-12.24], P = 0.046), history of tattooing (AOR = 2.86; 95%CI = [1.12-7.27], p = 0.03), and history of multiple sexual partner (AOR = 10.28; 95%CI = [4.16-25.38], P = 0.001) remained statistically significantly associated with HBsAg positivity.

CONCLUSION

This cross-sectional study identified that HBV infection is high among medical waste collectors in eastern Ethiopia. Immunization and on job health promotion and disease prevention measures should be considered in order to control the risk of HBV infection among medical waste collectors in eastern Ethiopia.

Prevalence, incidence and residual risk of transfusion-transmitted HBV infection before and after the implementation of HBV-NAT in northern Brazil

Background

Nucleic acid testing (NAT) for virus detection during blood screening has helped to prevent transfusion-transmitted infections worldwide. In northern Brazil, NAT was implemented in 2012 for HIV and HCV and more recently, in January 2015, the screening for HBV was included and currently used concomitant with serological tests (HBsAg and anti-HBc). This study aims to evaluate the prevalence and the incidence of HBV infection among voluntary blood donors at ten regional blood centers of HEMOPA Foundation in Pará state and to compare the residual risk of transfusion-transmitted HBV infection before and after the Brazilian HBV-NAT implementation.

Methods

The prevalence (restricted to first time donors- FT) and seroconversion rate (restricted to repeat donors- RP) of HBV were calculated based on rates of confirmed positive samples. Residual risk was based on the incidence and window period (WP) model described by Schreiber and coauthors. Logistic and Poisson regression were used in the statistical analysis by SPSS v20.0. A p value <0.05 was considered statistically significant.

Results

HBV prevalence in the periods before and after the implementation of HBV-NAT were 247 and 251 per 100,000 donations, respectively. Seroconversion rates were 114 and 122 per 100,000 donations in the two periods, respectively. The residual risk (RR) for HBV decreased significantly in the posterior period to the HBV-NAT implementation, when compared to RR before implementation, with a reduction of 1:144,92 to 1:294,11 donations (p <0,001).

Conclusions

The RR to HBV decreased after the implementation of HBV-NAT, increasing significantly the transfusional security in the North region of Brazil at HEMOPA Foundation.

[The francophone Africa blood transfusion research network: a five-year report]

There has been little blood safety research in sub-Saharan Africa, often consisting of local efforts whose findings had limited impact The "Francophone Africa Transfusion Research Network" was created in May 2007 with the objective of developing common evidence-based blood safety policies that may be adapted to each country's situation. The Group's activities to date have focused mainly on obtaining epidemiological and laboratory data on blood transfusion and on suggesting blood safety strategies, particularly in the field of TTIs. To carry out such research activities, the group works closely with the National Blood Transfusion Services (NBTS), the Regional Blood Transfusion Services (RBTS), the hospital blood banks (HBB) and collection stations. For the first 5years, four research priorities were identified: (i) descriptive studies of the characteristics of francophone African blood donors and blood centers; (ii) estimation of the residual risk of transfusion-transmitted major viral infections; (iii) an analysis of blood donor deferral strategies; and (iv) a description of TTI screening strategies and an external quality assurance system (EQAS) project. During this period, seven projects have been implemented at the national level and published and five multicenter studies were conducted and published. The present review reports the main observations and recommendations from those studies that could improve blood safety statute in Africa.

Residual Risk of Hepatitis-B-Infected Blood Donations: Estimation Methods and Perspectives

Despite a considerable reduction of the risk of HBV-infected blood donation entering blood supply (residual risk) due to improved screening by HBV NAT in the developed countries, the bulk of the people with HBV living in the developing countries still needs to be screened by serologic tests such as HBsAg and anti-HBc. Many of these countries lack resources for implementing NAT and are likely to remain so in the next decade or longer, thus depending on the HBV residual risk monitoring based on serologic testing and corresponding estimation methods. This paper reviews main HBV residual risk findings worldwide and the methods based on serology used for their calculation with repeat donors, as well as their extension to the first-time donors. Two artificial datasets with high (4.36%) and low (0.48%) HBV prevalence were generated to test the performance of five methods: the original incidence/window-period model based solely on HBsAg, its modification by Soldan in 2003, the Müller-Breitkreutz model, the HBsAg yield model, and its extension to include anti-HBc seroconversions within a year. The last model was closest to the true values of residual risk and had smallest variation of the estimates in both high and low prevalence data. It may be used for residual risk evaluation in relatively small samples, such as regional blood banks data.

[Prevalence and incidence of HIV and hepatitis B among blood donors and estimated residual risk of transmission of HIV and HBV virus by blood transfusion. A study at the Provincial General Referee Hospital Bukavu, Democratic Republic of the Congo]

BACKGROUND

To estimate the residual risk of transmission of HIV and HBV virus by blood transfusion in Bukavu.

METHODS

Retrospective cohort study designed for exploratory purposes, which took place in Bukavu (DR Congo) between January 2001 and December 2005, among 3292 blood donors. The incidences were estimated by survival curves and Cox models. The adjusted relative risks with their confidence interval at 95% were derived from Cox models. The residual risk of viral transmission associated with the serological window is equal to the incidence rate multiplied by the duration of the serological window divided by 365.

RESULTS

The prevalence among blood donors in Bukavu was 1% for HIV and 3.7% for HbsAg. The number of incident cases observed was seven for HIV and 40 for hepatitis B between 2001 and 2005. The incidence rates obtained were 3.57 for 1000 person-years (0.93/1000-6.23/1000) and 25.4 per 1000 person-years (17.6/1000-33.36/1000), respectively for HIV and hepatitis B. The residual risk was 1/4608 donations for HIV or 0.22 (0.02-0.65) and 1/257 donations for HBV or 3.90 (1.20-9.96). Also there were more seroconversions among family blood donors than in volunteer donors. The risk of seroconversion in family donors compared to volunteer donors adjusted for age, sex and residence was 7.09 (3.75-13.39) for HIV and 4.03 (2.63-6.20) for HBsAg. The same result was observed with the survival curves.

CONCLUSION

The prevalences of HIV and HBsAg in Bukavu are lower than in most major cities in sub-Saharan Africa. Residual risks are especially important for hepatitis B.

[Implementation of hemovigilance in Sub-Saharan Africa]

PURPOSE OF THE STUDY

Hemovigilance being an essential part of blood transfusion safety, many countries have set legislation for its organization and its establishment. In Sub-Saharan Africa, where transfusion practice is facing many challenges, hemovigilance does not always appear as a priority. Nevertheless, in 2000, Burkina Faso decided to reorganize its blood transfusion system according to the World Health Organisation recommendations and other international standards. A national blood transfusion center and regional blood transfusion centers were created. From 2005 to 2009, a hemovigilance pilot project was conducted by the regional blood transfusion center of Bobo-Dioulasso.

METHODS

The implementation of this hemovigilance project included the following steps: training of medical and paramedical personnel of the health facilities provided with blood and blood products by the regional blood transfusion center, distribution of post transfusion and hemovigilance forms, and the creation of a hemovigilance and transfusion committee.

RESULTS

During the period 2005-2009, 34,729 blood products were distributed for 23,478 patients. The return rate of the post-transfusion and hemovigilance forms (number of files completed partially or completely and returned to the regional blood transfusion center compared to the number of units distributed) raised from 83.1 to 94.8%, the rate of traceability (rate of forms returned to the regional blood transfusion center and totally completed) raised from 71.6 to 91.6%, and the concordance between the patient for which the blood was delivered and the patient transfused moved from 92.9 to 98.0%. The notification rate of transfusion incidents raised from 1.1 to 16.1 per 1000 units transfused during that period.

CONCLUSION

The implementation of a hemovigilance system is possible in the Sub-Sahara African countries. This constitutes a major element in the improvement of different steps of transfusion safety. The implementation of a hemovigilance system requires negotiations between transfusion centers and the hospital personnel, and should be facilitated by the official regulation on blood transfusion practices.

[Viral infection risk in polytransfused adults: seroprevalence of seven viruses in central Tunisia]

The aim of this study is to evaluate the prevalence of seven transfusion-transmitted viruses in polytransfused adults and children comparatively with a group of healthy control subjects. We studied 107 polytransfused patients (59 adults and 48 children) and 160 control subjects (100 blood donors and 60 children). Immunoenzymatic tests were used for detection of HBs antigen (HBs Ag), antibodies against hepatitis C Virus (anti-HCV), and human immunodeficiency virus (anti-HIV), and IgG antibodies against human cytomegalovirus (IgG anti-CMV), human parvovirus B19 (IgG anti-PB19), and hepatitis E virus (IgG anti-HEV). An immunofluorescent assay was performed for the detection of human herpesvirus 8 antibodies (anti-HHV8). Prevalence of HBs Ag, anti-HCV, anti-HIV, IgG anti-CMV, IgG anti-PB19, IgG anti-HEV, and anti-HHV8 in polytransfused group was 8.4, 4.7, 0, 86.9, 60.7, 28.9, and 47.6%, respectively, and 1.8, 0.6, 0, 86.2, 53.1, 10, and 12.5%, respectively, in the control group. The difference in prevalence between the two groups was statistically significant for HBs Ag (P = 0.01), anti-HCV (P = 0.03), IgG anti-HEV (P < 10(-4)), and IgG anti-HHV8 (P < 10(-4)). Categorization according to age showed that hepatitis B and C risk was limited in adult polytransfused group. HHV8 infection was higher in polytransfused subjects born before the use of leucocyte-depleted blood components. Our results corroborate literature data on the risk of HEV and HHV8 infection by blood transfusion. Hepatitis B vaccination and improvement in screening tests have an important role in reduction of hepatitis B and C risk in transfusion, especially in young polytransfused persons. However, a residual risk of transmitting viral infections persists, and efforts are needed to improve transfusion safety.

Moving on from voluntary non-remunerated donors: who is the best blood donor?

Blood transfusion safety in sub-Saharan Africa (SSA) is marred by the high prevalence of infectious agents, chronic blood shortage and lack of resources. However, considerable pressure is applied by richer countries and international transfusion bodies to establish voluntary, non-remunerated blood donors (VNRD) as the only source of blood, excluding the traditional family/replacement donors on the grounds of a higher level of safety. Such a policy increases the cost of a unit of blood by two to fivefold and exacerbates the pre-existing blood shortage. This review provides compelling evidence that first-time VNRD are no safer than family/replacement donors and that only repeat donation provides improved blood safety. In order to limit blood shortage and maintain affordability of the blood supply in SSA, both types of donors should be accepted and both should be encouraged to donate regularly.

The challenges of meeting the blood transfusion requirements in Sub-Saharan Africa: the need for the development of alternatives to allogenic blood

As a resource, allogenic blood has never been more in demand than it is today. Escalating elective surgery, shortages arising from a fall in supply, a lack of national blood transfusion services, policies, appropriate infrastructure, trained personnel, and financial resources to support the running of a voluntary nonremunerated donor transfusion service, and old and emerging threats of transfusion-transmitted infection, have all conspired to ensure that allogenic blood remains very much a vital but limited asset to healthcare delivery particularly in Sub-Saharan Africa. This is further aggravated by the predominance of family replacement and commercially remunerated blood donors, rather than regular benevolent, nonremunerated donors who give blood out of altruism. The demand for blood transfusion is high in Sub-Saharan Africa because of the high prevalence of anemia especially due to malaria and pregnancy-related complications. All stakeholders in blood transfusion have a significant challenge to apply the best available evidenced-based medical practices to the world-class management of this precious product in a bid to using blood more appropriately. Physicians in Sub-Saharan Africa must always keep in mind that the first and foremost strategy to avoid transfusion of allogenic blood is their thorough understanding of the pathophysiologic mechanisms involved in anemia and coagulopathy, and their thoughtful adherence to the evidenced-based good practices used in the developed world in a bid to potentially reduce the likelihood of allogenic blood transfusion in many patient groups. There is an urgent need to develop innovative ways to recruit and retain voluntary low-risk blood donors. Concerns about adverse effects of allogenic blood transfusion should prompt a review of transfusion practices and justify the need to search for transfusion alternatives to decrease or avoid the use of allogenic blood. These strategies should include the correction of anemia using pharmacological measures (use of antifibrinolytics to prevent bleeding and the use of erythropoietin and oral and intravenous iron to treat anemia) use of nonpharmacologic measures (preoperative autologous blood transfusion, perioperative red blood cell salvage and normothermia to reduce blood loss in surgical patients). All these strategies will help optimize the use of the limited blood stocks.

Risk behaviors in volunteer blood donors who seroconverted for HIV, Abidjan, Côte d'Ivoire 1997 to 2005

BACKGROUND

The residual risk of human immunodeficiency virus (HIV) transmission from blood products in the Abidjan National Blood Transfusion Center was estimated to be 1 in 5780 blood donations over the period 2002 through 2004. We aimed at describing risk behaviors in blood donors who seroconverted for HIV in Abidjan to improve the pre-blood donation selection.

STUDY DESIGN AND METHODS

We investigated the behavioral profile of HIV seroconverters assessed before their HIV diagnosis, during the blood donation selection at the blood bank of Abidjan, and compared it to the profile documented after this HIV diagnosis, at enrollment in the PRIMO-CI cohort. Since 1997, enrollment in this cohort is offered to every blood donor whose delay since HIV seroconversion was 36 months or less.

RESULTS

Among the 418 blood donors who seroconverted for HIV between 1997 and 2005, 241 were enrolled in the cohort. Median age was 28 years and 63% were men. The median time between the last HIV-negative test and the first positive test was 7 months. Since the last blood donation, 29% of donors reported unprotected sexual intercourse with multiple casual sexual partners, 55% unprotected sexual intercourse with one casual sexual partner, and 36% sharing of nail clippers. During the pre-blood donation questionnaire, 69% of HIV seroconverters had reported unprotected sexual intercourse since the last blood donation (vs. 89% reported after donation), and 7% had had multiple casual sexual partners (vs. 32%).

CONCLUSION

Volunteer blood donors who seroconverted for HIV in Abidjan reported a high proportion of unprotected sexual intercourse with casual sexual partners.

Deletions and recombinations in the core region of hepatitis B virus genotype E strains from asymptomatic blood donors in Guinea, west Africa

The prevalence of hepatitis B virus (HBV) surface antigen (HBsAg) chronic carriage in west Africa is the highest in the world, but its molecular epidemiology remains relatively poorly investigated. Plasma samples from random asymptomatic carriers of HBsAg in Conakry, Guinea, were studied and the complete genome sequences of 81 strains were obtained. Three additional samples from Kumasi, Ghana, were also included in the analysis. Phylogenetic analyses confirmed the dominance of genotype E (95.1%), including 8.6% of strains (viral load, 5x10(3)-2.6x10(8) IU ml(-1)) comprising dominant variants with large deletions in the core region and minority wild-type variants. The presence of two different patterns of deletions in two and four donors suggested targeted genome fragility between nt 1979 and 2314. The remaining sequences included one subgenotype A3 (1%) and six A/E recombinant forms (4-7%). A/E strains with identical points of recombination in three donors suggested strongly that these recombinant HBV strains are circulating and transmitted in the population. Recombination points were concentrated in the core gene. The detection of similar A/E recombinant strains in Ghana suggested a geographical extension of recombinant HBV to the region. The quasispecies of one additional Ghanaian strain sequenced in the pre-surface/surface region resolved into dominant clones of either the A or E genotype, but also three different patterns of A/E recombinant variants. The observation that both deletions of genotype E strains and A/E recombination points are mostly located in the core gene at specific positions indicates a region of the genome where genetic rearrangements preferentially take place.

Blood safety in Sub-Saharan Africa: a multi-factorial problem

Although the World Health Organization (WHO) has set targets for safe blood by 2012, Sub-Saharan Africa remains confronted with multi-factorial issues that compromise blood safety in most countries of the region. Some of these include the development and implementation of national policies for transfusion, the recruitment of voluntary and unpaid donors, proper screening of collected blood as well as a strategy for its rational use in a setting already plagued by a high prevalence of blood-borne agents, poverty, and sometimes organizational deficits. Furthermore, the organization of hemovigilance, as well as quality systems that could monitor transfusion practices is lacking in these settings. There is no funding and global improvement of blood safety has to be cheap to be feasible. Specific solutions for the African continent need to be developed and implemented. This paper examines the current status and difficulties of blood safety in Africa and reviews available data on transfusion medicine in the region.

Behavior Assessment of Blood Donors Facing the Risk of HIV Infection, Abidjan, Côte D'Ivoire, 2001-2002

Despite precautions taken to guarantee blood safety, in the National Blood Transfusion Center (CNTS) of Abidjan, about 30 regular blood donors are detected with HIV seroconversion each year, two-thirds of them men. A survey through face-to-face interviews was carried out at the CNTS of Abidjan from September 2001 to March 2002 among HIV-positive and HIV-negative regular blood donors, informed about their serologic status. HIV-negative regular blood donors informed about their serologic status since a median time of 67 months (n = 50) disclosed more risky behaviors such as multiple sexual partners (68%) than HIV-positive blood donors informed about their status (n = 112) since a median time of 35 months (41%) (P < 0.001). Condoms were systematically used by 17% of HIV-negative blood donors and 55% of HIV-positive blood donors (P < 0.001). Enhanced counseling and awareness could reduce in the future the number of cases of seroconversion among regular blood donors and improve their subsequent behavior. Blood donors who have unprotected sex with partners of unknown HIV serologic status and especially with casual partners are strongly exposed to HIV transmission and should be discouraged to continue giving blood, after adequate counseling.