[Prevalence of HIV, HTLV, and hepatitis B and C viruses in blood donors in France, 1992-1996]

Prevalence of hepatitis B and C in blood transfusion center, Oujda Morocco (2013-2015)

Viral hepatitis is a serious public health problem. Its epidemiology is not precisely known in Morocco. Our objective was to assess the prevalence of HBV and HCV in a particular population of "blood donors" at the Regional Blood Transfusion Centre in Oujda. A retrospective study was conducted from May 1, 2013 to May 31, 2015. Thirty-one thousand nine hundred and fifty-two blood donors were tested. Antigen detection was made according to ELISA technique (Monolisa^TMHBs Ag ULTRA). HCV research was performed by ELISA using the kit « Monolisa HCV Ag-Ab ULTRA ». 177 blood donors included, they are divided into 155 male (87.6%) and 22 female (12.4%) subjects with a ratio of 7. The average age was 37.64 ± 12 years. Six cases were positive for HCV with an overall prevalence of 0.02%. The population study by sex shows a prevalence of 0.004% for 23177 male sera and 0.057% for 8775 female sera. Six donors were HCV positive, of which 05 were female (83.33%) and one was male (16.66%). The average age was 43 ± 14 years. Co-infection with HCV HBV-HCV and HCV-Syphilis and HCV-HIV are absent. Co-infection with HBV and HIV was found in one case. HBV-syphilis co-infection was found in 04 cases. Chronic viral hepatitis is a real global health problem. Its prevalence is currently estimated at 0.55% for HBV and 0.02% for HCV, reclassifying Morocco as a low endemic area. The prevention remains the most effective method to successfully control HBV and HCV infection.

Twenty-Year Evolution of Hepatitis B Virus and Human Immunodeficiency Virus Prevalence and Incidence in Voluntary Blood Donors in Côte d'Ivoire

Background

Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) share common risk factors. The parallel description of their frequency over time may help capture their similarities and differences.

Methods

Using data from the National Transfusion Center of Abidjan, we estimated the following over a 20-year period: (1) the prevalence of HIV and hepatitis B surface antigen (HBsAg) positivity at first contact; and (2) the incidence of HIV and HBsAg seroconversion in negative first-time blood donors.

Results

Between 1992 and 2012, 422319 donors (men [M] = 74%) provided 1063825 blood donations. For first-time donors, HIV prevalence decreased from 7.1% (M = 5.9%, women [W] =11.0%) in 1992-1994 to 1.1% (M = 0.8%, W = 2.0%) in 2010-2012. Prevalence of HBsAg positivity remained stable at 10.8% (M = 11.7%, W = 7.3%) in 1992-1994 to 11.1% (M = 12.5%, W = 7.1%) in 2010-2012. Among regular donors (N = 129256), the incidence of becoming HIV or HBsAg positive, respectively, decreased from 4.9 per 100 (M = 4.5, W = 8.6) and 7.3 per 100 person-years (M = 7.8, W = 2.3) in 1992-1994 to 0.07 (M = 0.06, W = 0.11) and 0.2 per 100 person-years (M = 0.2, W = 0.2) in 2010-2012.

Conclusions

Human immunodeficiency virus prevalence and incidence decreased dramatically over time, whereas HBV prevalence remained stable. Incidence of HBsAg seroconversion, although decreasing, still reached unexpected levels, suggesting that the risk of HBV infection in adults may be higher than expected. Hepatitis B surface antigen-negative blood-donors should be offered HBV vaccination.

Donor-derived infection--the challenge for transplant safety

Unusual clinical syndromes or clusters of infections in recipients of organs from the same donor suggest donor-derived infection as a possible source of transmission

The incidence of transmission of unexpected infection by organ allografts is low, but precise data are lacking

Screening of donors for common pathogens involves both epidemiologic history and microbiological assays, and is highly effective for preventing the transmission of HIV and hepatitis B and C viruses

Donor screening for uncommon pathogens must be guided by knowledge of changes in the local epidemiology of infection

The key element in the detection of donor-derived infection is suspicion on the part of the clinicians caring for organ recipients

Application of newer microbiological techniques will increase the speed of donor screening and enhance transplant safety

Each year, over 70,000 organs are transplanted worldwide. The degree of risk of transmission of infection from transplanted organs to the recipient is largely unknown and is difficult to assess for specific organs. Here, Jay A. Fishman and Paolo A. Grossi describe the major risk factors for organ donor-derived transmission of infection and discuss opportunities to reduce the incidence of such events.

Organ transplantation, including of the heart, lung, kidney, liver, pancreas, and small bowel, is considered the therapy of choice for end-stage organ failure. Each year, over 70,000 organs are implanted worldwide. One donor may provide multiple organs, as well as corneas and other tissues, for multiple recipients. The degree of risk for transmission of infection carried with grafts, notably of viruses, is largely unknown and, for a specific organ, difficult to assess. The approach to microbiological screening of organ donors varies with national and regional regulations and with the availability and performance of microbiological assays used for potential donors. Transmission of both expected or common, and unexpected infections has been observed in organ transplants, generally recognized after development of clusters of infections among recipients of organs from a common donor. Other than for unusual or catastrophic events, few data exist that define the incidence and manifestations of donor-derived infections or the ideal assays to use in screening to prevent such transmissions. Absolute prevention of the transmission of donor-derived infections in organ transplantation is not possible. However, improvements in screening technologies will enhance the safety of transplantation in the future.

Opportunistic infections--coming to the limits of immunosuppression?

Possible etiologies of infection in the solid organ recipient are diverse, ranging from common bacterial and viral pathogens to opportunistic pathogens that cause invasive disease only in immunocompromised hosts. The recognition of infectious syndromes in this population is limited by alterations in the clinical manifestations by immunosuppression. The risk of serious infections in the organ transplant patient is determined by the interaction between the patients' recent and distant epidemiological exposures and all factors that contribute to the patient's net state of immune suppression. This risk is altered by antimicrobial prophylaxis and changes in immunosuppressive therapies. In addition to the direct effects of infection, opportunistic infections, and the microbiome may adversely shape the host immune responses with diminished graft and patient survivals. Antimicrobial therapies are more complex than in the normal host with a significant incidence of drug toxicity and a propensity for drug interactions with the immunosuppressive agents used to maintain graft function. Rapid and specific microbiologic diagnosis is essential. Newer microbiologic assays have improved the diagnosis and management of opportunistic infections. These tools coupled with assays that assess immune responses to infection and to graft antigens may allow optimization of management for graft recipients in the future.

Transmission of infection with human allografts: essential considerations in donor screening

Transmission of infection via transplantation of allografts including solid organs, eyes, and tissues are uncommon but potentially life-threatening events. Donor-derived infections have been documented following organ, tissue, and ocular transplants. Each year, more than 70 000 organs, 100 000 corneas, and 2 million human tissue allografts are implanted worldwide. Single donors may provide allografts for >100 organ and tissue recipients; each allograft carries some, largely unquantifiable, risk of disease transmission. Protocols for screening of organ or tissue donors for infectious risk are nonuniform, varying with the type of allograft, national standards, and availability of screening assays. In the absence of routine, active surveillance, coupled with the common failure to recognize or report transmission events, few data are available on the incidence of allograft-associated disease transmission. Research is needed to define the optimal screening assays and the transmissibility of infection with allografts. Approaches are reviewed that may contribute to safety in allograft transplantation.

An autoregressive integrated moving average model for short-term prediction of hepatitis C virus seropositivity among male volunteer blood donors in Karachi, Pakistan

AIM: To identify the stochastic autoregressive integrated moving average (ARIMA) model for short term forecasting of hepatitis C virus (HCV) seropositivity among volunteer blood donors in Karachi, Pakistan.

METHODS: Ninety-six months (1998-2005) data on HCV seropositive cases (1000^-1× month^-1) among male volunteer blood donors tested at four major blood banks in Karachi, Pakistan were subjected to ARIMA modeling. Subsequently, a fitted ARIMA model was used to forecast HCV seropositive donors for 91-96 mo to contrast with observed series of the same months. To assess the forecast accuracy, the mean absolute error rate (%) between the observed and predicted HCV seroprevalence was calculated. Finally, a fitted ARIMA model was used for short-term forecasts beyond the observed series.

RESULTS: The goodness-of-fit test of the optimum ARIMA (2,1,7) model showed non-significant autocorrelations in the residuals of the model. The forecasts by ARIMA for 91-96 mo closely followed the pattern of observed series for the same months, with mean monthly absolute forecast errors (%) over 6 mo of 6.5%. The short-term forecasts beyond the observed series adequately captured the pattern in the data and showed increasing tendency of HCV seropositivity with a mean ± SD HCV seroprevalence (1000^-1× month^-1) of 24.3 ± 1.4 over the forecast interval.

CONCLUSION: To curtail HCV spread, public health authorities need to educate communities and health care providers about HCV transmission routes based on known HCV epidemiology in Pakistan and its neighboring countries. Future research may focus on factors associated with hyperendemic levels of HCV infection.

Prevalence of hepatitis C infection and risk factors in hospitalized diabetic patients: results of a cross-sectional study

OBJECTIVES

Although there may exist a nosocomial risk of hepatitis C virus (HCV) infection in patients with type 1 or type 2 diabetes, this risk has not been fully investigated thus far and its magnitude is unknown. The aim of this multicenter cross-sectional study was to evaluate the prevalence of, and risk factors for, hepatitis C infection in consecutive hospitalized patients with diabetes and to assess the nosocomial risk and magnitude of HCV infection in these patients.

PATIENTS AND METHODS

Consecutive hospitalized patients with diabetes seen in 11 French hepatogastroenterology and diabetology departments were studied. The prevalence of anti-HCV antibodies was compared with that observed in healthy blood donors and individuals seen during routine medical checkup. Diabetic patients with anti-HCV antibodies were compared with patients without anti-HCV antibodies for assessment of risk factors.

RESULTS

In total 1561 patients were studied. Independent risk factors for HCV infection were assessed through multivariate analysis. Thirty-three patients (2.11%) had anti-HCV antibodies and 21 (63.70%) had HCV identified risk factors. The prevalence of HCV infection was higher in patients with diabetes than in blood donors (0.08%) or healthy controls (0.20%) (P<0.001). Multivariate analysis identified four independent risk factors for HCV infection: blood transfusion before 1991 [odds ratio (OR)=2.88, P=0.033], intravenous drug use (OR=21.37, P=0.012), treatment in a hepatogastroenterology center (OR=4.17, P=0.002) and a high number (>2) of previous admissions since the onset of diabetes (OR=2.52, P=0.039).

CONCLUSION

A nosocomial source of HCV infection in hospitalized diabetic patients is suggested by the increased risk of HCV infection associated with the number of hospitalizations. This may account for at least 36% of cases of HCV infection.

Comparison of the risk of viral infection between the living and nonliving musculoskeletal tissue donors in Australia

Screening of musculoskeletal tissue donors with nucleic acid testing (NAT) for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) has been implemented in the United States and other developed nations. However, in contrast to the donor demographics in the United States, the majority of Australian musculoskeletal tissue donations are primarily from living surgical donors. The objective of our study was to determine and compare the risk of viral infection associated with musculoskeletal tissue donation from living and nonliving donors in Australia. We studied serum samples from 12 415 consecutive musculoskeletal tissue donors between 1993 and 2004. This included 10 937 surgical donations, and 1478 donations obtained from postmortem organ donation patients and cadaveric donors. Current mandatory retesting of surgical donors 6 months postdonation reduces the risk of viral infection by approximately 95% by eliminating almost all donors in the window period. The addition of nucleic acid amplification testing for nonliving donors would similarly reduce the window period, and consequently the residual risk by approximately 50% for hepatitis B virus, 55% for HIV, and 90% for HCV. NAT, using appropriately validated assays for nonliving donors, would reduce the residual risk to levels comparable to that in living donors (where the 95% reduction for quarantining pending the 180-day re-test is included).

The risk of HIV, HBV, HCV and HTLV infection among musculoskeletal tissue donors in Australia

In Australia, there are no current national estimates of the risks of transmission of human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) or human T-lymphotrophic virus (HTLV) by musculoskeletal tissue transplantation. We determined the prevalence rates of antibodies against HIV (anti-HIV), HCV (anti-HCV) and HTLV (anti-HTLV) and Hepatitis B surface antigen (HBsAg) for 12,415 musculoskeletal tissue donors from three major bone tissue banks across Australia for the period 1993-2004. The prevalence (per 100,000 persons) was 64.44 for anti-HIV, 407.13 for HBsAg, 534.63 for anti-HCV and 121.88 for anti-HTLV. The estimated probability of viremia at the time of donation was 1 in 128,000, 1 in 189,000, 1 in 55,000 and 1 in 118,000, respectively. With the addition of nucleic acid amplification testing (NAT), the probability of donor viremia would be reduced to 1 in 315,000 for HIV, 1 in 385,000 for HBV and 1 in 500,000 for HCV. The prevalence of HIV, HBV, HCV and HTLV although low, are higher among musculoskeletal tissue donors than among first-time blood donors. The risks associated with musculoskeletal donation will be reduced with NAT, though further cost analysis is required prior to its implementation.

Epidemiologic study of chronic hepatitis B virus infection in male volunteer blood donors in Karachi, Pakistan

Background

The magnitude of chronic infection with hepatitis B virus (HBV) varies substantially between the countries. A better understanding of incidence and/ or prevalence of HBV infection and associated risk factors provides insight into the transmission of this infection in the community. The purpose of this investigation was to estimate the prevalence of and to identify the risk factors associated with chronic infection with HBV, as assessed by HBV surface antigen (HBsAg) positivity, in asymptomatic volunteer male blood donors in Karachi, Pakistan.

Methods

Consecutive blood donations made at the two large blood banks between January 1, 1998 and December 31, 2002 were assessed to estimate the prevalence of HBsAg positivity. To evaluate the potential risk factors, a case-control study design was implemented; cases (HBsAg positives) and controls (HBsAg negatives), were recruited between October 15, 2001 and March 15, 2002. A pre-tested structured questionnaire was administered through trained interviewers to collect the data on hypothesized risk factors for HBV infection. Sera were tested for HBsAg using commercially available kits for enzyme linked Immunosorbant assay-III.

Results

HBsAg prevalence in the male volunteer blood donors was 2.0 % (7048/351309). Multivariate logistic regression analysis showed that after adjusting for age and ethnicity, cases were significantly more likely than controls to have received dental treatment from un-qualified dental care provider (adjusted odds ratio (OR) = 9.8; 95% confidence interval (CI): 2.1, 46.1), have received 1–5 injections (adjusted OR = 3.3; 95% CI: 1.1, 9.6), more than 5 injections (adjusted OR = 1.4; 95% CI: 1.4, 12.7) during the last five years or have received injection through a glass syringe (adjusted OR = 9.4; 95% CI: 2.6, 34.3). Injury resulted in bleeding during shaving from barbers (adjusted OR = 2.3; 95% CI: 1.1, 4.8) was also significant predictor of HBsAg positivity.

Conclusion

Prevalence of HBsAg positivity in the male volunteer blood donors in Karachi was 2%. Infection control measures in health-care settings including safe injection practices and proper sterilization techniques of medical instruments and education of barbers about the significance of sterilization of their instruments may reduce the burden of HBV infection in this and similar settings. There is also an urgent need of developing locally relevant guidelines for counseling and management of HBsAg positive blood donors.

La responsabilité du médecin prescripteur de produits sanguins labiles

Blood transfusion presents mainly virological, bacteriological, immunohaematological and volemic risks; with the latter two particularly concerning health establishment employees. This article tackles the physician's responsibility in blood transfusion. Taking into account the regulations that surround the activity, prescribing physicians must know and put into action the relative requirements in their practises in order to avoid taking on its responsibility, or that of the health establishment in which they work, as any lack of respect for the rules and regulations could result in being held liable for any side affects suffered by the patient. The article has the objective of identifying the main regulation requirements in order to control them despite a difficult environment, from the point of view of patients' rights regarding the benefits and the consequences of transfusion. These requirements focus mainly on information and patient consent, the prescription of blood products as well post transfusion information and the follow-up care. Proof of respect for these rule requirements must be available for each of these aspects.

Cloning and expression of surface antigens from occult chronic hepatitis B virus infections and their recognition by commercial detection assays

Occult hepatitis B virus (HBV) infections show little or no serological markers of viral infection, including the absence of hepatitis B surface antigen (HBsAg) which is the main marker of ongoing HBV infection. Such infections can be important in the context of blood and/or organ donations. To study whether mutations contribute to HBsAg seronegativity, S gene sequences from such patients were amplified and cloned. Sequencing revealed 12 clones from seven different patients which contained potentially important mutations. The sequences were subcloned into an expression vector and mutant HBsAgs were expressed in cell culture. The capacity of three HBsAg detection assays to recognise the mutant HBsAgs was studied. Three categories were found: mutant HBsAgs that are not recognised by the assays, those that are recognised as well as wild-type (WT) antigen and an intermediate category where detection of the mutant HBsAgs is reduced with respect to WT. Most of the isolates fall into the second category. Mutations can therefore contribute to HBsAg seronegativity in occult HBV infections, but in most cases the explanation is probably the low level of viral replication.

Potential exposure to hepatitis C virus through accidental blood contact in interventional radiology

PURPOSE

To quantify the prevalence of accidental blood exposure (ABE) among interventional radiologists and contrast that with the prevalence of patients with hepatitis C virus (HCV) undergoing interventional radiology procedures.

MATERIALS AND METHODS

A multicenter epidemiologic study was conducted in radiology wards in France. The risk of ABE to radiologists was assessed based on personal interviews that determined the frequency and type of ABE and the use of standard protective barriers. Patients who underwent invasive procedures underwent prospective sampling for HCV serologic analysis. HCV viremia was measured in patients who tested positive for HCV.

RESULTS

Of the 77 radiologists who participated in 11 interventional radiology wards, 44% reported at least one incident of mucous membrane blood exposure and 52% reported at least one percutaneous injury since the beginning of their occupational activity. Compliance with standard precautions was poor, especially for the use of protective clothes and safety material. Overall, 91 of 944 treated patients (9.7%) tested positive for HCV during the study period, of whom 90.1% had positive viremia results, demonstrating a high potential for contamination through blood contacts.

CONCLUSIONS

The probability of HCV transmission from contact with contaminated blood after percutaneous injury ranged from 0.013 to 0.030; the high frequency of accidental blood exposure and high percentage of patients with HCV could generate a risk of exposure to HCV for radiologists who perform invasive procedures with frequent blood contact. The need to reinforce compliance with standard hygiene precautions is becoming crucial for medical and technical personnel working in these wards.

[Prevalence of HBV, HCV, HIV and HTLV in autologous blood donors in France between 1993 and 2000]

The epidemiological surveillance of autologous blood donors has been carried out in France since 1993. The number of autologous donors increased regularly from 1993 to 1997 but has decreased during the last three years to become less than 50,000 in 2000. The sex-ratio was stable over time (0.85 male for 1 female). The population of autologous donors grew older between 1993 and 2000: the proportion of those aged under 50 years old decreased from 29% in 1993 to 18% in 2000 while the proportion of those over 69 increased from 22 to 34%. Between 1993 and 2000, HbsAg prevalence decreased by a factor of 2.5 and HCV prevalence by a factor of 5. For HIV, a slight decrease was observed and the prevalence of HTLV was stable over time. In 2000, HCV prevalence (0.23%) was two times higher than HBsAg prevalence (0.12%), fifteen times higher than HTLV prevalence in Continental France (0.015%) and one hundred times higher than HIV prevalence (0.002%). The prevalence was similar in men and women for HCV, about two times higher in men than in women for HBsAg and three times higher for HIV. On the contrary, HTLV prevalence was about two times higher in women than in men. HBsAg and HCV prevalence rates were also calculated by age group. The prevalence rates for HBsAg increased up to the 30-39 age group among women and the 40-49 age group among men; then the rates decreased but were higher in men than in women. For HCV, while the prevalence increased continuously with age among women, a peak was reached for men in the 30-39 age group followed by a decrease up to the 50-59 age group and the prevalence was stable afterwards. The very low level of the current risk of transmitting viral infections by homologous transfusion and technical changes in autologous transfusion seem to be the two main factors that contributed to the recent decline in the number of autologous donors. The decrease in HBsAg and anti-HCV prevalence between 1993 and 2000 is multifactorial, but the drop observed for HCV is probably linked to a decrease in HCV prevalence of the general population over the last ten years.

Incidence rates of viral infections among repeat donors:are frequent donors safer?

BACKGROUND

Incidence rates (IRs) for viral infections may vary with the frequency of donation among repeat, community, whole-blood (WB) donors, with IRs thought to be lower among donors with higher frequency of donation.

STUDY DESIGN AND METHODS

IRs for HIV, HTLV, HCV, and HBV infection were stratified by frequency of donation among 868,403 repeat WB donors who gave approximately 4 million donations at five United States blood centers from 1991 through 96. All donors had given at least 2 donations during those years, with the first donation being nonreactive on confirmatory testing. Frequency of donation was measured in three ways: by the number of donations per year; at the time of donation, by the number of donations given within the preceding 2-year period; and by the number of donations given from 1991 through 1993.

RESULTS

The IRs for HIV, HCV, and HBV infection did not appear to differ among donors with lower or higher numbers of donation per year. However, the IR for HTLV infection decreased as the number of donations per year increased (p = 0.0004). IRs for all viral markers remained stable, regardless of the number of donations given within the 2-year period before the donation. Although IRs for HIV, HTLV, and HCV infection did not vary by the number of donations given in 1991 through 1993, the IR for HBV infection appeared to be lower in donors who gave more donations in that period (p = 0.01).

CONCLUSION

These findings do not provide evidence of a lower IR for transfusion-transmissible viral infections among repeat WB donors who give more frequently. Abbreviated screening histories for frequent repeat donors might not be advisable.

Including polymerase chain reaction in screening for hepatitis C virus RNA in blood donations is not cost-effective

BACKGROUND AND OBJECTIVES

To assess the cost and effectiveness of adding a system of polymerase chain reaction (PCR) testing to the current enzyme-linked immunosorbent assay (ELISA) screening for hepatitis C virus (HCV) in blood donations.

MATERIALS AND METHODS

We performed a cost-effectiveness analysis comparing three HCV screening strategies in French blood donors: detection of antibodies against HCV by an ELISA on blood donations (the current policy) vs. ELISA and PCR either on each blood donation or on blood pools. We combined national surveillance data on HCV antibody-positive blood donors with a literature review in a Markov model for natural history of HCV disease and its treatment.

RESULTS

PCR testing performed in parallel with ELISA will potentially add less than 1 year of life for all French recipients compared to ELISA screening alone. The incremental costs per life year saved were, respectively, epsilon84.6 million with ELISA and PCR testing of blood pools, and epsilon891.1 million with testing of individual blood donations.

CONCLUSION

PCR testing performed in parallel with antibody screening, either on pools or on single donations is not currently a cost-effective option for the detection of HCV RNA virus in blood donors.

Hepatitis C virus: routes of infection and genotypes in a cohort of anti-HCV-positive French blood donors

BACKGROUND

We evaluated and analysed risk factors of HCV-infected blood donors according to HCV genotypes in order to improve the transfusion policy and safety of blood supply.

MATERIALS AND METHODS

HCV-RNA was analysed in sera from 518 anti-HCV-positive blood donors, who were invited to medical consultation and interview as to risk factors by means of an extensive questionnaire. HCV genotyping was done on all samples positive for HCV-RNA.

RESULTS

Of the 518 sera, 399 (77%) were HCV-RNA positive, and 394 of 399 HCV genotypes were identified. Major genotypes were 1b (34.3%), 3a (24%), 1a (19.5%) and 2 (11.4%). Of the donors, 289 (55.8%) were interviewed regarding their risk behaviour: 27% were former intravenous drug users (IVDUs), 26% had been transfused, 8% had a history of invasive diagnostic procedures, and 13% a history of surgery. Among the 224 interviewed donors, genotypes 1a and 3a were mainly associated with IVDU (51 and 45% respectively) and genotype 1b, with transfusion and nosocomial infections (40 and 25%, respectively).

CONCLUSION

In this population of anti-HCV-positive blood donors, nosocomial infection may be a route of HCV spread, but the main risk factor remains IVDU, particularly in young men. The transfusion policy will improve if predonation interviews of such young men are done with a specific and sensitive questionnaire.

[Viruses and unconventional transmissible agents: update on transmission via blood ]

The blood borne viruses must be separated into major and minor agents. Major viruses transmissible by blood transfusion are human immunodeficiency virus (HIV) and hepatitis B and C viruses (respectively HBV, HCV). The prevalence of virological markers in French blood donors has been continuously decreasing since the implementation of serological screening methods as soon as they were available. In 1998, the prevalences (per 10,000 donations) were 0.17 for antibody to HIV, 0.08 for antibody to human T-cell leukemia virus (HTLV), 2.23 for hepatitis B surface antigen (HBs Ag) and 2.52 for antibody to HCV. The values are, of course, higher in new donors when compared to regular donors: approximately five-fold for HIV, 50-fold for HCV and 300-fold for HBs Ag. The remaining major questions concern the residual risk due to infectious donations which could escape the preventive measures. It seems evident that the major risk is imputable mainly to donations collected during the window period. During the 1996-1998 period, the residual risk for HIV was 1 out of 1,350,000 donations, 0 for HTLV, 1 out of 375,000 for HCV, and 1 out of 220,000 for HBV. A few cases of "immunosilent" patients have been reported. They remain exceptional. The first data collected after the implementation of nucleic acid technology (NAT) confirm the very low residual risk. The recent introduction of leukodepletion probably brought an important contribution to diminishing the risk of transmission of leucotropic viruses such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesviruses-6, -7 and -8, and HTLV. If the purification process of plasma-derived medicinal products including inactivation procedures makes it possible to be confident with the elimination of infectivity due to enveloped viruses, the detection of nucleic acid sequences derived from naked viruses in plasma pools such as parvovirus B19 or hepatitis A virus (HAV), and/or the introduction of a nanofiltration step during the purification process, when possible, may greatly contribute to their safety. The emergence of a new form of the Creutzfeldt-Jakob disease (nvCJD) introduces a new series of questions about the safety of blood products that, although the risks appear limited, are not yet resolved.

[Screening for markers of infections transmitted by transfusions in the blood collected in France from 1996 to 1998]

From 1996 to 1998, a decrease in positive donation rates has been observed for HIV, HCV and HBs Ag in first-time donors, while these rates remained stable for HTLV. In repeat donors, the same decrease was observed for HCV and HBs Ag while the rates remained stable for HIV. No HTLV-positive donations from repeat donors were noted in 1998. About half of the HIV-positive repeat donors were regular donors (less than two years between the two donations), as well as 88% of HBV-infected repeat donors. Inversely, only 20% of HCV-positive repeat donors were regular donors. Anti-HBc antibodies have been found in 20% of HIV-infected donors, in 22% of HCV-infected donors, and were associated with HBs Ag in 99% of the cases. Elevated ALT was observed in 47% of donors with anti-HCV and in 10% of donors with HBs Ag. The major risk factors are at-risk sexual behavior for HIV and use of intravenous drugs and nosocomial infections for HCV. Being a native of an endemic country has been found to be the major risk for HBV. The major HTLV risk factor was directly or indirectly linked to the Caribbean area.

[Controlled viral risks]

The prevalence of virological markers in blood donors has been continuously decreasing since the implementation, as soon as they were available, of serological screening methods. In 1998, the prevalences (per 10,000 donations) were 0.17 for antibody to HIV, 0.08 for antibody to HTLV, 2.23 for HBs Ag and 2.52 for antibody to HCV. The values are of course higher in new donors when compared to regular donors: approximately five-fold for HIV, 50-fold for HCV and 300-fold for HBs Ag. The remaining major questions concern the residual risk due to infectious donations which could escape the preventive measures. It seems evident that the major risk is imputable mainly to donations collected during the window period. During the 1996-1998 period, the residual risk for HIV was one out of 1,350,000 donations, 0 for HTLV, one out of 375,000 for HCV, and one out of 220,000 for HBV. A few cases of 'immuno-silent' patients have been reported. They remain exceptional. The first data collected after implementation of Nucleic Acid Technology (NAT) confirm the very low residual risk. The molecular epidemiology of the concerned viruses applied to the evaluation of screening assays highlighted the impact of the genetic diversity on the efficiency of these assays. This is particularly evident for HIV and HBV. The recent introduction of leucodepletion probably brought an important contribution in diminishing the risk of transmission of leucotropic viruses such as cytomegalovirus, Epstein-Barr viruses, human herpesviruses 6 and 7, and HTLV. If the purification process of plasma derived medicinal products including inactivation procedures permits confidence in the elimination of infectivity due to enveloped viruses, the detection of nucleic acid sequences derived from naked viruses in plasma pools may greatly contribute to their safety.

[Risk behavior among blood donors: efficacy of a new questionnaire]

The clinical selection of volunteers for blood donation is essential to reduce the risk of viral transmission by blood transfusion. The aim of this study was to evaluate a new questionnaire for a pre-donation medical interview. This questionnaire was developed by transfusion practitioners, epidemiologists and professional investigators, and focused on risk behaviors of blood donors and their partners. Five blood banks in the French Ile-de-France region (around Paris), participated in the study from May 1995 to January 1996. All participating doctors were specifically trained by professional investigators. The sex and the age of donors, the type of collection, the duration of interviews and the reasons for exclusion from donation were recorded. The results were compared to those of a prior study dealing with a sample of 15,000 donors presenting the same characteristics, whose blood was taken of at the same collection sites in 1993. Of the 1,527 volunteers donating blood, 14% were interviewed in fixed centers and 86% by moving teams (38% in firms, 22% in towns, 13% in civil service facilities, 13% in school or academic centers). For 15.9% of the volunteers, this was the first donation (range: 7.3% in fixed centers to 41.5% in school and academic centers). The mean duration of the interview was 11 min (10 min for volunteers included, 14 min for donors excluded from donation). It decreased from 14 min at the beginning of the study to 10 min by the end of the study. The percentage of donors excluded for risk behavior (3.7% in 1995-96 vs 1.5% in 1993, P < 0.001), or medical reasons (12.2% in 1995-96 vs 8.4%, in 1993, P < 0.001) was significantly greater in 1995-96 than in 1993 (15.9% vs 9.9%, P < 0.001). In 1995-96, 35.0% of exclusions for risk behavior were related to male homosexuality, multiple partners or the risk behavior of the partner vs 12% in 1993 (P < 0.001). The risk of exclusion was 5.5 times higher for donors not living in a couple. The results obtained demonstrated the value of this new approach to the medical interview.