Transfusion-transmitted Viral Infections Research Articles

Clinical significance of viral markers testing by ELISA and Individual Donation Nucleic Acid Testing (ID-NAT) for blood screening in blood bank: Single center study in Egypt

Prevention of transfusion-transmitted viral infections and insurance of safe blood transfusion are the main goals of all blood banks worldwide. Despite the high sensitivity and specificity of currently used enzyme linked immunosorbent assay (ELISA) for hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) testing, viral transmission could still occur during the window period. Introducing viral individual donation nucleic acid testing (ID-NAT) can greatly decrease such risk providing an additional layer in securing blood transfusion. We aimed to assess the clinical significance of viral markers testing by ELISA and ID-NAT for blood screening in the Blood Bank of Suez Canal University Hospital. We studied all donations (2132) collected during a two-months period. Blood donor samples were screened by ELISA and ID-NAT tests for HBV, HCV, and HIV. Serological testing results for HCV by ELISA revealed 2,122 (99.5 %) negative donations compared to 2,131 (99.95 %) negative donations by ID-NAT testing. Of the positive ELISA samples, only one was NAT positive. For HBV ELISA testing, 2,115 (99.2 %) donations were negative, also by ID-NAT testing 2,115 (99.2 %) donations were HBV DNA negative. Out of the negative ELISA samples, two samples were ID-NAT reactive donors which were missed by serology assay being in the window period. HIV ELISA testing revealed negative 2,130 (99.9 %) donations while ID-NAT testing showed 2,131 (99.95 %) negative donations and one positive donation. In conclusion, this is the first study carried out in the Suez Canal and Sinai region, Egypt to assess the importance of ID-NAT implementation. The introduction of ID-NAT in blood banks is an effective method for increasing safety of the blood transfusion.

Human immunodeficiency virus, hepatitis C virus and hepatitis B virus incidence in blood donors from 2000 to 2020 in France: Trends and lessons from haemovigilance surveillance.

Data from 21 years (2000-2020) of haemovigilance were used to assess human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) incidence rates in repeat blood donors and the occurrence of transfusion-transmitted (TT) viral infections. Blood donors who converted for HIV, HCV or HBV markers within serial three-year analysis periods were included. Epidemiological and virological data were retrieved from the national epidemiological donor database and were supplemented with information on blood components and the infection status of recipients of the previous negative donation (D.N-1) of donors who seroconverted. Incidence rates declined from 1.27 to 0.35/100,000 person-years for HIV, from 0.59 to 0.19 for HCV and from 1.66 to 0.18 for HBV. Risk factors and lookback for 232 HIV, 90 HCV and 74 HBV seroconversions were investigated. The main risk factor identified at post-donation interview was having sex with men (47.8% of males) for HIV and a sexual risk for HCV (30.6%) and HBV (37.1%). The viral loads and sequences were retrospectively tested in 191 HIV, 74 HCV and 62 HBV D.N-1 archived samples. Six (five HBV and one HIV-1) were positive all low viral loads. Two recipients were infected by red blood cells from two HBV seroconverting donors before the introduction of HBV-nucleic acid testing. HIV, HCV and HBV incidence rates in blood donors declined over the two past decades in France. There is a very small risk of a blood component that tests negative entering the blood supply resulting in TT infections, especially after introduction of molecular assays in donor screening.

Seroprevalence and trends of hepatitis B virus, hepatitis C virus and human immunodeficiency virus in Syrian blood donors at Damascus University Blood Center between 2004 and 2021.

Seroprevalence of transfusion-transmitted viral infections (TTVIs) is a valuable indicator for assessing blood safety, population health and health system performance in the times of peace and conflicts. Only scarce information is available on the impact of the decade-long violent conflict on the prevalence of TTVIs in Syria. Moreover, hepatitis B vaccine was introduced to the national vaccination program in 1993; however, no data is available on the vaccine effectiveness. In this retrospective cross-sectional study, we compiled the screening results for major TTVIs, namely hepatitis B virus (HBV), hepatitis C virus (HCV), and human immuno-deficiency virus (HIV), of volunteer donors at Damascus University Blood Center from May 2004 to October 2021. Prevalence was expressed in percentages for the entire study group and subgroups. Chi-square test and linear regression were used to examine the differences and describe trends in prevalence, respectively, based on demographic characteristics (i.e., age and gender) and time. P-value of <0.005 was considered statistically significant. Of the total 307,774 donors (82.27% males, median age 27 years), 5,929 (1.93%) had serological evidence of at least one TTVI, and 26 (0.0085%) had multiple infections. The lowest prevalence (1.09%) was detected in donors aged 18-25 years old, and a higher prevalence (2.05%) was evident in males in comparison with females (1.38%). The seroprevalence of HBV, HCV, and HIV was 1.18, 0.52, and 0.23%, respectively. Trend analyses revealed a significant regression in HBV and HIV prevalence from 2011 to 2021. HBV seropositivity depicted a temporal decline by ~80%, from 0.79% in 2011 to 0.16% in 2021 in those born in 1993 and thereafter. The seroprevalence of HBV, HIV, and to a lesser extent HCV dropped over the study 18-year period. Possible explanations may include implementation of the HBV vaccine, robust national health system, conservative sociocultural values, and isolation.

Seroprevalence of hepatitis B, hepatitis C, and human immunodeficiency virus in hemophilia A patients: A descriptive study

Background: Hemophilia A (Factor VIII deficiency) is a X-linked coagulopathy that affects approximately 1/10,000 male live births. In the past, the treatment of hemophilia A consisted of cryoprecipitated plasma and purified factor preparations. As a result, they experienced unusually high incidence of hepatitis and human immunodeficiency virus (HIV) seroconversion. Aims and Objectives: The aims of this study were to find out the seroprevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV infection, among hemophiliacs attending a tertiary care center in Kerala, southern India. Materials and Methods: A cross-sectional study was conducted on hemophilia A patients who attended the departments of medicine and pediatrics. Demographic details and treatment history were obtained by questionnaire. Enzyme-linked immunosorbent assay was used to detect HBV surface antigen, HCV antibodies, and HIV. The statistical data analysis was performed using SPSS software version. Results: Out of 90 hemophilia A patients who underwent testing for the seroprevalence of transfusion-transmitted viral infections, one (1.1%) patient tested positive for HIV, two (2.2%) for HCV, and one (1.1%) for HBV. Among patients with hemophilia A, the prevalence of transfusion-transmitted infection was 4.4%. Patients with HIV- and HCV-positive tests belonged to the severe hemophilia A group. Moreover, the HBV-positive patient belonged to moderate hemophilia A. Conclusion: The present paradigm of management of hemophilia A patients is with plasma-derived or recombinant Factor VIII concentrates, cryoprecipitates, and fresh frozen plasma. Due to the risk, however remote, of transfusion-transmitted viral infections, all hemophiliacs should receive the hepatitis B vaccine and undergo routine testing for HIV, HCV, and HBV viruses.

Viruses Special Issue “Transfusion-Transmitted Viral Infections”

Blood transfusion is a life-saving treatment that requires patients to have access to safe and adequate blood products that are available in a timely manner [...].

The Effect of Viruses on Blood Transfusion, an Applied Study on the Hafr Al-Batin Blood Bank

The fact that blood groups can act as receptors/coreceptors for bacteria, viruses, and parasites demonstrates the importance of blood groups in infection. Blood group antigens also aid in cell adsorption, signal transmission, and/or membrane micro-domain retention. Furthermore, blood type can influence the innate immune response to infection. This data was compiled using the risk perception of blood transfusion scale, which is part of a larger risk perception questionnaire. Blood transfusion risk perception is measured on a 7-point Likert scale based on a set of qualitative characteristics; 119 participants in Hafr Al-Batin blood bank had a significant difference in risk perception of blood transfusion due to receiving blood, whereas those who had never received blood had no risk perception. as much risk perception of blood transfusion, and because of viral hepatitis infection, those who did not have viral hepatitis had more risk perception of blood transfusion, but there is no significant difference in risk perception of blood transfusion due to gender, age, educational level, and blood donation. The implementation of strict donor pre-screening and preventative measures to control infections in the general population, as well as the introduction of new, more sensitive screening tests, could significantly reduce transfusion-transmitted viral infections across eastern Saudi Arabia.

Antibacterial Action of Visible 405-nm light for Bacterial Reduction in Blood Plasma

The introduction of risk prevention measures, such as blood screening and donor deferrals have dramatically reduced the incidence of transfusion-transmitted viral infections. Nevertheless, bacterial contamination of blood transfusion products remains a concern to patient health, and a range of pathogen reduction technologies have been developed to reduce this risk. Visible violet-blue light, in the region of 405-nm, has recently demonstrated potential for in situ treatment of ex vivo stored plasma and platelet products, without the need for additional photosensitizers. This study assessed the broad-spectrum efficacy of 405-nm light against a range of bacteria implicated in transfusion-transmitted infections: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniaeandYersinia enterocolitica. Plasma was seeded with clinically-relevant low-level bacterial contamination (102-103CFUmL-1) and exposed to a 405-nm light dose of 360 Jcm-2 (1-hr at 100mWcm-2) using a small-scale exposure system. Broad spectrum antibacterial efficacy was observed, with 99.0 – 100% inactivation achieved for all bacterial species tested. Bacterial inactivation tests were then scaled-up to expose large volumes of prebagged plasma seeded with S. aureusat ~103 CFUmL-1, to 22mWcm-2 405-nm light, under agitation, (≤396 Jcm-2). Successful bacterial inactivation was observed using the large-scale exposure system, with a dose of 238 Jcm-2 (3-hr at ~22mWcm-2) achieving complete (3.5-log10) reductions in prebagged bacterial-seeded plasma (P=0.001). Results from this study support further development of visible 405-nm light technology as a bactericidal tool for application in transfusion medicine. This abstract reflects the views of the author and should not be construed to represent FDA’s views or policies.

Overt and occult hepatitis B among immigrants and native blood donors in Madrid, Spain.

Background:The risk of transfusion-transmitted viral infections is very low in developed countries. Recent massive migration flows from highly hepatitis B virus (HBV), hepatitis C virus (HCV) and/or HIV endemic regions to Europe may have changed this scenario.Methods:During 2017 and 2018, a total of 491,753 blood donations (291,762 donors) were evaluated at the Madrid Regional Transfusion Center. All were tested for hepatitis B surface antigen (HBsAg), anti-HCV and anti-HIV, as well as for HBV-DNA, HCV-RNA and HIV-RNA.Results:Overall, 35 donors were positive for HIV-RNA and 26 for HCV-RNA. HBV markers were found in 111 (0.022%) donors, split out into three categories: HBsAg+ (n = 93; 0.019%), occult B infection (OBI) (n = 17; 0.003%), and acute HBV window period (n = 1; 0.0002%). All 17 OBI donors were positive for anti-HBc and confirmed as viremic in repeated testing. Viral load amounts were uniformly below 100 IU/mL. Ten OBI donors were repeated donors and look-back studies could be completed for eight of them. Fortunately, none of all prior recipients experienced transfusion transmitted hepatitis B. Compared with HBsAg+ donors, OBI donors were more frequently native Spaniards (76% versus 40%) and older (median age 52 versus 42 years old).Conclusion:Active HBV infection is currently found in 0.022% of blood donations (0.038% of donors) in Madrid. This rate is 3-fold greater than for HIV and/or HCV. On the other hand, HBsAg+ donors are 3-fold more frequent than OBI donors and more often immigrants than native Spaniards. No transfusion-transmitted HBV infections were identified during the study period, including retrospective checking of former recipients of OBI donors.

Confirming transfusion-transmitted viral infections in the molecular age: time to get back to the basic definition of infection for hemovigilance.

Confirming transfusion-transmitted viral infections in the molecular age: time to get back to the basic definition of infection for hemovigilance.

Evolution of the residual risk of HBV, HCV and HIV transmission through blood transfusion in the Region of Valencia, Spain, during a 15-year period (2003-2017).

Towards the end of the 20th century, transfusion-transmitted viral infections (TTVI) represented a huge problem for public health. From the beginning of the screening of blood donations, this risk has decreased to the point that it is no longer possible to measure it directly and it is necessary to use mathematical models. Using one of these models, the aim of this study was to analyse the evolution of the residual risk of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) transmission through blood transfusion from 2003 to 2017 in the Region of Valencia, Spain. Using data from the Blood Transfusion Centre of the Valencian Community, the incidence rate in donors and the residual risk were calculated for each agent and year by applying the most updated version of the incidence/window period model. For the set of the three viruses, these magnitudes were calculated as the algebraic sum of the specifics ones for each of them. The evolution of both magnitudes was analysed by the Mann-Kendall trend test and the Sen estimation of trend slope. The residual risks obtained vary depending on the agent and the year. Considering the three viruses jointly, they range from 1 per 360,380 to 1 per 44,715 donations. During the study period, there was a statistically significant downward trend in the incidence rate of HBV (p<0.05, trend slope -0.88), the residual risk of HBV (p<0.0005, slope -0.98), and the joint residual risk for the three viruses (p<0.0001, slope -0.99). The current risk of TTVI is very low in the Region of Valencia. In the last 15 years, there has been a reduction in the donor incidence rate and in the residual risk for the case of HBV; such a reduction cannot be confirmed for HCV and HIV. Consideration of the three viruses jointly confirms a reduction in the residual risk; we are unable to establish whether the evolution of the joint incidence rate has contributed to this reduction or whether it is due only to the shortening of window periods.

Role of Nucleic Acid Test (NAT) in Detection of Transfusion Transmitted Viruses in Comparison to Other Methods

Background: over the two last decades, much attention has been given to the prevention of transfusion-transmitted viral infections. Given the potential transmission of viruses during the window period, novel non-serology based approaches such as viral nucleic acid testing (NAT) have been established. Objective: a comparative study of different methods to detect transfusion transmitted viral infections. Materials and methods: this cross-sectional study was conducted at the Egyptian National Blood Transfusion Center (NBTC), Giza. The duration of the research was 2 months from June 2018 to august 2018. In our study 1000 donor samples were tested by ELISA and NAT tests for HBV, HCV and HIV. Results: regarding ELISA tests of the three viruses, only 14 (1.4%) samples were finally HBsAg reactive. Finally, reactive HCVAb were 22 (2.2%) samples, while only 4 (0.4%) samples were HIV Ag-Ab finally reactive. We found highly statistical significant difference between initial and final results of ELISA (p<0.001). Regarding NAT testing of the three viruses. HBV: 5 (0.5%) samples were NAT and ELISA reactive, 1 was NAT yield. HCV: 9 (0.9%) samples were NAT and ELISA reactive. HIV one sample (0.1%) was NAT and ELISA reactive, one (0.1%) was NAT yield. Statistical significant difference was found in comparison between NAT and ELISA in HBV, HCV, and HIV p values <0.001, <0.001, and = 0,008 respectively. Conclusion: we concluded that NAT and ELISA are complementary to each other. NAT is an effective method for safeguarding the blood supply.

Frequency of Hepatitis B core antibody and Hepatitis B Virus DNA among apparently healthy male blood donors in Eastern Libya

Background/Objectives: Hepatitis B virus (HBV) infection represents one of the most serious blood transfusion-transmitted viral infections. By implementation of the hepatitis B surface antigen (HBsAg) screening assay, blood banks in Libya have been considerably increased blood transfusion safety in term of protecting against the transmission of HBV infection. However, several studies demonstrated that donors who are HBsAg negative and hepatitis B core antibody (anti-HBc) positive maybe a potential source for posttransfusion hepatitis B. The aim of this study is to determine the presence of anti-HBc and HBV DNA (hepatitis B viral DNA) in healthy HBsAg-negative blood donors in eastern Libya (Tobruk region). Materials and Methods: A total of 500 serum samples were tested for HBsAg and obtained from healthy blood donors in blood bank unit in Tobruk Medical Center. All donors were tested for anti-HBc, using commercial ELISA and microwell methods (MBS-SRL, Milano, Italy). The reactive samples were further tested for the presence of HBV DNA using polymerase chain reaction (PCR). Results: In this study, the seroprevalence rate of anti-HBc sample was 54 (10.8%) among donors. The majority of anti-HBc-positive cases (52 of 54) were in the age group of 20–49 years. Of the 54 anti-HBc-positive samples, 4 (7.4%) were tested positive for HBV DNA by PCR. Conclusion: Among all the samples, the rate of anti-HBc was 10.8%. This finding is comparable to a previous study performed in northwestern Libya. The present study estimated the expected exclusion rate of anti-HBc-positive donated blood that would be an important factor to consider before adopting anti-HBc testing in addition to HBsAg testing as a mandatory screening test to further enhance transfusion safety.

Incidence and Residual Risk of HIV, HBV and HCV Infections Among Blood Donors in Tehran.

Estimation of residual risk is essential to monitor and improve blood safety. Our epidemiologic knowledge in the Iranian donor population regarding transfusion transmitted viral infections (TTIs), is confined to a few studies based on prevalence rate. There are no reports on residual risk of TTIs in Iran. In present survey, a software database of donor records of Tehran Blood Transfusion Center (TBTC) was used to estimate the incidence and residual risk of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections, by applying the incidence rate/window period (IR-WP) model. A total of 1,207,155 repeat donations was included in the analysis and represented a mean of 8.4 donations per donor over 6years. The incidence amongst repeat donors was estimated by dividing the number of confirmed seroconverting donors by the total number of person-years at risk. The residual risk was calculated using the incidence/window period model. Incidence rate and residual risk for HBV, HCV and HIV infections were calculated for total (2005-2010) and two consecutive periods (2005-2007 and 2008-2010) of the study. According to the IR-WP model, overall residual risk for HIV and HCV in the total study period was 0.4 and 12.5 per million units, respectively and for HBV 4.57/100,000 donations. The incidence and residual risk of TTIs, calculated on TBTC's blood supply was low and comparable with developed countries for HIV infection but high for HCV and HBV infections. Blood safety may therefore be better managed by applying other techniques like nucleic acid amplification tests.

Prevalence of hepatitis B, hepatitis C, and human immunodeficiency virus infections among hemophilia patients in Shiraz, south of Iran

Transfusion-transmitted viral infections, including hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV) infections continue to be a major challenge in hemophilia patient. This study was conducted to assess the seroprevalence of HBV, HCV, and HIV infections among Iranian hemophilia patients. A cross-sectional study was conducted on 580 hemophilia patients (mean age ± SD = 27.11 ± 14.9) referred to the Namazi hospital, Shiraz University of medical sciences, Shiraz, Iran during July 2012 to August 2015. Blood samples were taken from the patients and tested for HBV surface antigen (HBsAg), antibody to HBV surface antigen (anti-HBs), antibody to HBV core antigen (anti-HBc), anti-HCV antibody (HCVAb), and anti-HIV antibody (HIVAb). The association of HBV, HCV, and HIV infections with age, sex, type of hemophilia (A or B), severity of hemophilia, blood group system, history of blood transfusion, and surgery were statistically analyzed using SPSS software and chi-square/Fisher exact tests. The seroprevalence of HCVAb and HBsAg were 11.4 % (66/580) and 0.2 % (1/580), respectively. None of the hemophilia patients were positive for HIV antibody. There was a significant association between HCV seropositivity and age (P < 0.001), severity of hemophilia (P < 0.0001), and history of blood transfusion (P = 0.050). It seems that strategies for prevention of HBV and HIV infections have been successful in south of Iran, but HCV is still a major infection of concern in multi-transfused patients.

Automated nucleic acid amplification testing in blood banks: An additional layer of blood safety.

Context:A total of 30 million blood components are transfused each year in India. Blood safety thus becomes a top priority, especially with a population of around 1.23 billion and a high prevalence rate of human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) in general population. Nucleic acid amplification testing (NAT) in blood donor screening has been implemented in many developed countries to reduce the risk of transfusion-transmitted viral infections (TTIs). NAT takes care of the dynamics of window period of viruses and offers the safest blood pack for donation.Aims:The aim of this study is to show the value of NAT in blood screening.Settings and Design:Dhanavantari Blood Bank, Rajahmundry, Andhra Pradesh, India.Subjects and Methods:Over a period of 1 year from January 2012 to December 2012, a total number of 15,000 blood donor samples were subjected to tests for HIV, HBV, and HCV by enzyme-linked immunosorbent assay (ELISA) method and 8000 ELISA nonreactive samples were subjected for NAT using multiplex polymerase chain reaction technology.Results:Of the 15,000 donors tested, 525 were seroreactive. In 8000 ELISA negative blood samples subjected to NAT, 4 donor samples were reactive for HBV. The NAT yield was 1 in 2000.Conclusions:NAT could detect HIV, HBV, and HCV cases in blood donor samples those were undetected by serological tests. NAT could interdict 2500 infectious donations among our approximate 5 million annual blood donations.

Estimating window period blood donations for human immunodeficiency virus Type 1, hepatitis C virus, and hepatitis B virus by nucleic acid amplification testing in Southern Pakistan

Recently, strategic planning was initiated by the National Blood Transfusion Services Pakistan to improve its blood bank facilities. Emphasis has been placed on appropriate screening of blood products. Located in the southern region, Aga Khan University Hospital is a 700-bed tertiary care academic institute with comprehensive blood banking. Screening of blood donors has been based on verbal screening and serologic testing to date. Additionally, the need of implementing nucleic acid testing (NAT) was considered in 2011 because of an upsurge in hepatitis epidemiology. The aim of this study was to analyze the efficacy of this additional donor screening program and to evaluate the impact of NAT on the yield and residual risk of transfusion-transmissible viral infections. A total of 42,830 blood donations collected between 2011 and 2012 were screened for routine serologic assays. Only serologically negative donors (n=41,304) were tested for NAT. The frequency of viral infections was evaluated through serologic techniques and NAT yield for viral agents was estimated for computing window period donors. Residual risk per million donors was computed for viral infections in seronegative blood donors. Serologic work-up showed 1571 abnormal screening results in 1526 blood donors with the following results: hepatitis C virus antibodies (anti-HCV; n=708), hepatitis B surface antigen (n=555), human immunodeficiency virus antibodies (anti-HIV; n=29), malaria (n=30), VDRL (n=249), and coinfection (n=45). Thirty-five NAT-reactive samples were identified: HIV-1, one; HCV, 27; and hepatitis B virus (HBV), seven. Incident rates per 10(5) donors were highest for HCV (453.3) followed by HBV (171.5) and HIV (72.2). Calculated residual risk per million donors was highest at 1 in 10,900 for HBV, intermediate at 1 in 13,900 for HCV, and least at 1 in 62,600 for HIV. Incidence rates and estimated residual risk indicate that the current risk of transfusion-transmitted viral infections attributable to blood donation is relatively high in this country. The study recommends the parallel use of both serology and NAT screening of donated blood in countries that have high seroprevalence of these viral infections.

Incidence of Transfusion-Transmitted Viral Infections in the Hematology Department of Baghdad Teaching Hospital

Incidence of Transfusion-Transmitted Viral Infections in the Hematology Department of Baghdad Teaching Hospital

Le groupe de recherches transfusionnelles d’Afrique francophone : bilan des cinq premières années

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.

The risk of transfusion-transmitted viral infections at the Gabonese National Blood Transfusion Centre.

Blood transfusions carry the risk of transmitting blood-borne infections. In contrast to the situation in the developed world, there is a limited number of studies examining this problem in sub-Saharan Africa. In this study we aimed to calculate the risks of acquiring human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infection from units of blood issued by the Gabonese Blood Transfusion Centre between 2009 and 2011. All the donations were tested for infectious diseases and the seroconversion incidence rates of HIV, HBV and HCV were calculated. The residual risk of transfusion-associated transmission for each virus was calculated by multiplying the seroconversion rates by the window period expressed in fractions of a year. The risks of becoming infected with HIV, HCV, and HBV in subjects receiving units of blood from the Gabonese Blood Transfusion Centre were 64.7, 207.94 and 534.53 per million donations, respectively. This study, which is the first to quantify the true risks of transfusion-transmitted infections in Gabon, reveals and confirms the need to reinforce preventative and screening strategies to improve transfusion safety in sub-Saharan Africa.

Evolução do Risco Residual Infeccioso para o VIH, VHC e VHB, nas Dádivas de Sangue do Centro Hospitalar de S. João, entre os Anos de 1999 e 2010

Monitoring the residual risk of transfusion-transmitted viral infections is important to evaluate the improvement achieved in the blood donation safety and to adopt policies to reduce risks. The present study calculates the incidence of the key infectious diseases, human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) as well as the residual risk of transfusion-transmitted viral infections, during twelve years, 1999 through 2010. Data were analyzed over 3 periods of 4 years (1999-2002, 2003-2006 and 2007-2010). The risk estimates were compared to those previously obtained for blood donations occurred between 1991 and 1998. The study included 209 640 blood donations, from 42 634 regular, volunteers and unpaid donors. The residual risk of transfusion-transmitted infection per million donations was calculated, for each virus, through mathematical model "Incidence rate/window period", described by Schreiber et al. All donations were screened according to Portuguese legislation. In January 2001, the nucleic acid testing in minipool was implemented on all blood donations, for screening simultaneously HIV-1 and HCV ribonucleic acid (RNA) (Cobas Amplicor Ampliscreen-Roche©). This test was replaced, in January 2007, by the simultaneous screening of HBV deoxyribonucleic acid, HCV RNA and HIV-1/HIV-2 RNA, in minipool (Cobas Taqscreen MPX Test-Roche©). The residual risk of transmitting viral infections during the transfusion of blood components is very small and has declined over the years. After the implementation of the nucleic acid testing in minipool for the three viruses, the risk of giving blood during an infectious window period was estimated as follows: for human immunodeficiency virus, 1 in 1.67 million, for hepatitis C virus 1 in 3.33 million and for hepatitis B virus 1 in 526 000. During the 12 years under study, we found a decrease in residual risk for the three viruses, by a factor around five for human immunodeficiency virus and hepatitis B virus, and 32 for hepatitis C virus. If we compare the estimates previously calculated for 1991-1998 period to 2007-2010 period (over 20 years), the decrease is still more relevant with a residual risk of human immunodeficiency virus, hepatitis B virus and hepatitis C virus respectively 19-fold, 6-fold and 54-fold lower.