Two-year follow-up of donors in a large national study of ferritin testing.

BACKGROUND: We assessed donor return rates, donation frequency, and factors related to the evolution of ferritin levels 2 years after entering donors into a large operational study of ferritin testing. STUDY DESIGN AND METHODS: Ferritin testing was done on donors from representative clinics (n = 12,595). Low-ferritin donors (<25 µg/L) were informed and not called for 6 months to book a donation. Approximately 37% of donors had ferritin retested on a return donation. Return rate and donation frequency were monitored, and a logistic regression model was constructed. RESULTS: The return rate was lower in low-ferritin donors (67% vs. 78%), particularly in women who were first-time donors (36% vs. 61%). Returning low-ferritin donors made fewer donations in the 2 years after notification compared to the 2 years prenotification (4.5 vs. 7.5 for men, 3.0 vs. 5.0 for women), while donation frequency was lower and increased slightly for normal-ferritin donors (4.7 vs. 4.4 for men, 3.6 vs. 3.1 for women). An increased number of donations, shorter interdonation intervals, female sex, and younger age are associated with low ferritin levels on initial and repeat testing. Some recovery of ferritin occurred, but most low-ferritin donors continued to have low or borderline levels on retesting. CONCLUSION: Informing donors of low ferritin results had a long-lasting impact on return rates and donation frequency, requiring recruitment efforts to maintain adequacy of supply. Increasing the interdonation interval leads to some improvement in ferritin levels; more sustained efforts to encourage donors to improve iron intake are needed to achieve long-term benefit.

Assignment of cytomegalovirus infection status in infants awaiting solid organ transplant: Viral detection methods as adjuncts to serology.

Assignment of CMV infection status in infants awaiting SOT is challenging as passive maternal antibody can lead to false-positive serology. Since 2000, our protocol has recommended sending throat and urine samples for CMV viral detection, culture, or NAAT, for CMV-seropositive infants <18 months awaiting SOT. We reviewed pretransplant CMV serology for 152 infants and, for CMV seropositives, examined relationships between CMV IgG OD values, age, and CMV viral detection to explore time to clearance of maternal CMV IgG and evaluate viral detection in assignment of pretransplant CMV infection status. The proportion of CMV-seropositive infants decreased from 52% in infants 0-6 months of age to 28% in those 12-18 months. Among CMV-seropositive infants, median OD was significantly higher in the 6- to 12- and 12- to 18-month groups compared to the 0- to 6-month group. Distribution of OD by age group suggested that maternal antibody cleared before 12 months. Of 59 eligible CMV-seropositive infants, 49 (83%) had CMV viral detection studies and 18 of 49 (36.7%) had detectable CMV: 9 of 30 (30.0%) infants 0-6 months, 7 of 15 (46.7%) infants 6-12 months, and 2 of 4 (50.0%) infants 12-18 months. CMV viral detection studies are useful to confirm positive CMV infection status in CMV-seropositive infants awaiting SOT. Maternal CMV IgG likely clears before 12 months.

A large national study of ferritin testing in Canadian blood donors.

BACKGROUND: We assessed risk groups for iron deficiency and the feasibility and efficacy of ferritin testing in a large blood center. STUDY DESIGN AND METHODS: Donors were informed of possible testing in the predonation pamphlet. Plasma ferritin was measured on retention samples (n = 12,595) from representative clinics. Low-ferritin donors (<25 µg/L) were sent a letter and information sheet and not called for 6 months. Ferritin testing was repeated on 25% of donors; donor return rate and frequency were monitored. RESULTS: Low-ferritin donors represented 2.9% of first-time and reactivated (no donation in past 12 months) male donors, 32.2% of first-time and reactivated female donors, 41.6% of repeat male donors, and 65.1% of repeat female donors. A mean of 11.7 months after index donation, the return rate was 76% for normal and 58% for low-ferritin donors; returning low-ferritin donors had made approximately one fewer donation. Ferritin increased by 16.3 and 12.1 µg/L in male and female low-ferritin donors and decreased by 17 µg/L in male and female normal-ferritin donors. CONCLUSION: The minimum hemoglobin level will be increased to 130 g/L for male donors and the minimum interdonation interval changed to 84 days (four donations yearly) for female donors based on iron deficiency risk groups. Large-scale ferritin testing was feasible. Donors informed of low-ferritin results had a lower return rate, donated less often, and had an increase in ferritin on return, approximately 1 year after initial testing, compared to donors with normal ferritin results.

Hepatitis E in Canadian blood donors.

BACKGROUND: Hepatitis E virus (HEV) is a virus of emerging importance to transfusion medicine as studies on blood donors and other populations demonstrate that the prevalence of endemic cases is higher than previously recognized and the risk to vulnerable transfusion recipients is not insignificant. STUDY DESIGN AND METHODS: We carried out an HEV prevalence study on 13,993 Canadian blood donors with polymerase chain reaction (PCR) testing on all donors and antibody testing on a subset of 4102 donors. HEV antibody-positive and age- and sex-matched antibody-negative donors were invited to participate in a scripted telephone interview about risk factors. RESULTS: There were no PCR-positive samples found (95% confidence interval [CI], 0%-0.026%). The seroprevalence of HEV in our tested population was 5.9% (95% CI, 5.16%-6.59%). HEV antibody positivity was associated with male sex and increasing age. In case-control analysis history of living outside Canada (odds ratio [OR], 2.9; 95% CI, 1.56-5.32) and contact with farm animals (OR, 1.5; 95% CI, 1.01-2.28) were associated with HEV seropositivity. CONCLUSION: This is the largest data set to date on HEV infection in Canada. Results suggest low lifetime exposure to HEV and that infectious donations are rare.

Residual risk of HIV, HCV and HBV in Canada.

BACKGROUND: Residual risk is estimated as the product of the incidence and the infectious window period, the time during which a blood donation could be infectious but the assay may not detect it. In 2011 nucleic acid multiplex testing (MPX) was implemented in 6 unit minipools (previously 24 unit minipools). MPX also included hepatitis B (HBV) NAT for the first time (complementing HBsAg screening) in addition to HIV-1 and hepatitis C (HCV) as before. We aimed to estimate window period risk-day equivalents for MPX, and the residual risk of viral infections in blood donations updated to reflect current incidence and testing. METHODS: Transmissible disease conversions of repeat donations to Canadian Blood Services within the three-year period 2012-2014 divided by person-years estimated incidence for HIV, HCV and HBV (adjusted for transient viremia). Window period risk-day equivalents for MPX were estimated using a published method. Residual risk was the product of incidence and window period risk-day equivalents. 95% confidence intervals were estimated using Monte Carlo simulation of the window period risk-day equivalents and the incidence density 95% confidence intervals. RESULTS: The incidence rate per 100,000 person years for HIV was 0.28, HCV 1.0 and HBV 0.26. The residual risk of HIV was 1 per 21.4 million donations, HCV 1 per 12.6 million donations and HBV 1 per 7.5 million donations. CONCLUSION: The residual risk of infection is very low, similar to 2006-2009. The safety benefit of further shortening of the infectious window period is below the threshold to quantify.

Impact of informing donors of low ferritin results.

BACKGROUND: Informing donors of their ferritin status is one possible mitigating strategy to reduce iron deficiency in donors. STUDY DESIGN AND METHODS: We evaluated the impact of informing donors of their ferritin status on their donation frequency, understanding of iron needs, and actions to improve iron intake 2 years after their inclusion in a prospective observational cohort study. RESULTS: Informing donors of low ferritin results decreased return rate in first-time and repeat donors, and the median number of donations declined from three to two donations/year in returning donors with low ferritin on index donation compared to an increase from 1.5 to 2.5 donations/year in donors with normal ferritin. An electronic questionnaire demonstrated that approximately 60% of low ferritin donors saw their primary medical practitioner, and half of this group started iron. Qualitative interviews revealed suboptimal understanding of iron needs and poor compliance with iron supplementation. CONCLUSION: Providing donors with results of ferritin testing may reduce return rates and donation frequency in the 2 years after testing. Simply providing donors with ferritin results and an information sheet is often inadequate to improve donors' understanding of iron needs and may not lead to a substantive increase in iron intake over time.

Seroprevalence of Babesia microti infection in Canadian blood donors.

BACKGROUND: Human babesiosis, caused by the intraerythrocytic protozoan parasite Babesia microti, is primarily transmitted by tick bites and is also transmitted by transfusion. Infections have been identified in U.S. blood donors close to Canadian borders. We aimed to assess the risk of transfusion-transmitted babesiosis in Canada by examining infections in ticks and seroprevalence in blood donors. STUDY DESIGN AND METHODS: Passive surveillance (receipt of ticks submitted by the public) was used to identify regions for tick drag sampling (active surveillance, 2009-2014). All ticks were tested for B. microti using an indirect immunofluorescent antibody assay (Imugen, Inc.). Between July and December 2013, blood donations from selected sites (southern Manitoba, Ontario, Québec, New Brunswick, and Nova Scotia) near endemic U.S. regions were tested for antibody to B. microti. Donors completed a questionnaire about risk travel and possible tick exposure. RESULTS: Of approximately 12,000 ticks submitted, 14 were B. microti positive (10 in Manitoba, one in Ontario, one in Québec, two in New Brunswick). From active tick surveillance, six of 361 ticks in Manitoba were positive (1.7%), three of 641 (0.5%) in Québec, and none elsewhere. There were 26,260 donors at the selected sites of whom 13,993 (53%) were tested. None were positive for antibody to B. microti. In 2013, 47% of donors visited forested areas in Canada, and 41% traveled to the United States. CONCLUSION: The data do not suggest that laboratory-based testing is warranted at this time. However, there are indicators that B. microti may be advancing into Canada and ongoing monitoring of tick populations and donor seroprevalence is indicated.

Incidence of gammopathies in long-term plasmapheresis donors at Canadian Blood Services.

BACKGROUND: To investigate the long-term consequences of repeated plasmapheresis on donor health, their donation histories and demographic data were reviewed to determine the frequency of development of monoclonal (Mc) gammopathies or other gamma globulin abnormalities (OGGAs). STUDY DESIGN AND METHODS: Samples from apheresis plasma donors collected at Canadian Blood Services were tested initially and every 4 months for total protein (TP) followed by serum protein electrophoresis (SPE). Out-of-range samples or those showing abnormal band patterns were forwarded to a hospital laboratory for additional investigation. RESULTS: Of 52,972 donors who donated 471,446 apheresis plasmas over 9 years, 89,490 samples were sent for TP and SPE testing. Of 3005 samples forwarded for further investigation, abnormal immunofixation electrophoresis (IFE) results were found in 209 (0.4%) donors, 85 from first-time (FT) and 124 from repeat (RPT) plasma donors during participation in the program. There were 167 donors with Mc gammopathies (73 FT, 94 RPT) and 42 with OGGAs (12 FT, 30 RPT). FT or RPT donors with Mc gammopathies or OGGAs were significantly older than those with normal SPEs. RPT donors with Mc gammopathies or OGGAs also had a longer donation period than donors with normal SPEs. CONCLUSIONS: The incidence of Mc gammopathies (2.41 per 1000 donors) did not significantly increase from 2004 to 2012. Older donors had a higher incidence of Mc gammopathies and longer donation periods than their healthy counterparts. Overall, gammopathy rates were below those reported over the same age range in the general population.

Iron deficiency in Canadian blood donors.

BACKGROUND: The adequacy of communication and knowledge of donors and physicians regarding iron needs and the relationship between hemoglobin (Hb) and iron stores require evaluation to address donor iron deficiency. STUDY DESIGN AND METHODS: A prospective cohort study was performed on 550 successful donors and 50 donors deferred for low Hb (<125 g/L on repeat fingerstick). Donors participated in an on-clinic interview and had serum ferritin measured. They were mailed their results and recontacted regarding follow-up. RESULTS: Most donors are unaware of possible health impacts of donation and do not discuss donation with their physician. In successful donors, mean ferritin levels were 37 and 131 µg/L in first-time and reactivated (no donation for 2 years) females and males and 19 and 29 µg/L in frequent repeat females and males, respectively (p < 0.0001), with infrequent donors having intermediate results. Mean ferritin was 12 µg/L in donors deferred for low Hb. Twenty of 22 donors failing initial Hb testing and passing on repeat testing had ferritin below 25 µg/L. On follow-up, 63 of 164 donors (38%) with low ferritin were taking iron supplements 2 months postdonation. CONCLUSION: Iron deficiency is frequent, particularly in female donors and frequent donors. A fail on initial Hb testing followed by a pass on repeat testing is likely to be due to iron deficiency and borderline anemia. Donors and physicians need to be more aware of iron needs associated with blood donation and appropriate treatment for low iron stores.

Evaluation of selective screening of donors for antibody to Trypanosoma cruzi: seroprevalence of donors who answer "no" to risk questions.

BACKGROUND: Selective testing of donors for Trypanosoma cruzi infection relies on identification of at-risk donors with screening questions. Using risk modeling and a seroprevalence study, we evaluated the risk of questions failing to identify T. cruzi antibody-positive donors. STUDY DESIGN AND METHODS: The rate of donors with unreported risk was estimated by a telephone survey of 2677 donors who answered "no" to risk questions. The number of T. cruzi antibody-positive donors missed by risk questions was estimated from the product of this rate and the selective testing T. cruzi antibody-positive rate. The 95% confidence interval (CI) was estimated by Monte Carlo simulation. To test the model, 60,132 donors were tested for T. cruzi antibody (26% of donors in selected regions, Phase I). In Winnipeg, Manitoba, the highest-risk region, 26,915 donors were tested (92.5% of donors, Phase II). RESULTS: In the telephone survey, 21 (0.8%) donors reported risk factors that would have identified them for selective testing. Seven were born in Mexico or Central or South America, five had travel risk, and nine had mother or maternal grandmother risk. The 95% CI for predicted number of T. cruzi antibody-positive donors answering "no" to risk questions was 0.71 to 4.38. In Phase I, one Winnipeg donor confirmed positive but had answered risk questions correctly. No other positive donations were identified. CONCLUSION: The estimated risk of T. cruzi-positive donors who answer "no" to risk questions is low and is confirmed by the seroprevalence among these donors.

Selective testing for Trypanosoma cruzi: the first year after implementation at Canadian Blood Services.

BACKGROUND: Various testing strategies may reduce the risk of Chagas disease transmission in nonendemic, low-prevalence countries. Results of the first year of selective testing of at-risk donors at Canadian Blood Services are reported. STUDY DESIGN AND METHODS: Since February 2009, platelets were not produced from at-risk donors. Since May 2010, at-risk donors were tested for Trypanosoma cruzi antibodies. Donors testing positive were interviewed about risk factors, and lookback studies were initiated. RESULTS: There were 7255 at-risk donors of 421,979 donors screened (1.72%). Risk factors were born in Latin America (50.6%), mother or maternal grandmother born in Latin America (28%), and 6 months or more travel history or residence in Latin America (19%). Sixteen (16) at-risk donors had T. cruzi repeat-reactive test results of whom 13 confirmed positive. Eleven of 13 were born in Latin America (nine in Paraguay and two in Argentina), and the other two were born in Canada but had short-term travel history and mothers who had been born in Latin America. Ten of the donors spoke German as their first language (all of those born in Paraguay and one born in Canada). There were 148 previous donations (176 components transfused) evaluated by lookback, of which 28% of recipients could be tested. None were positive. CONCLUSION: Selective testing has mitigated a small risk to the blood supply with very few false-positive results. Most positive donors were born in a risk country, with a concentration of German-speaking immigrants from Paraguay. Residency or travel alone were not clear risk factors.

A case of vertical transmission of Chagas disease contracted via blood transfusion in Canada.

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and is endemic in many countries in Latin America, where infected bugs of the Triatominea subfamily carry the parasite in the gut and transmit it to humans through fecal contamination of a bite. However, vertical transmission and transmission through blood transfusion and organ transplantation is well documented. Increasing immigration from endemic countries to North America has prompted blood operators, including Canadian Blood Services and Hema Quebec, to initiate blood donor testing for Chagas antibody. In the present report, an unusual case of vertical transmission from a mother, most likely infected through blood transfusion, and detected as part of a concurrent seroprevalence study in blood donors is described.

La maladie de Chagas est causée par le parasite protozoaire Trypanosoma cruzi. Elle est endémique dans de nombreux pays d'Amérique latine, où des insectes infectés de la sous-famille des Triatominea sont porteurs du parasite dans leur intestin et le transmettent aux humains par contamination fécale secondaire à une morsure. Cependant, la transmission verticale, par transfusion sanguine et par transplantation d'organe, est bien étayée. L'immigration croissante de pays endémiques en Amérique du Nord a incité les organismes transfusionnels, y compris la Société canadienne du sang et Héma-Quebec, à amorcer le dépistage de l'anticorps de la maladie de Chagas dans le sang des donneurs. Dans le présent rapport, les chercheurs décrivent un cas inhabituel de transmission verticale par la mère, probablement infectée par une transfusion sanguine, dépistée dans le cadre d'une étude concomitante sur la séroprévalence chez les donneurs de sang.

Evaluation of particle gel immunoassays for the detection of severe immunoglobulin A deficiency and anti-human immunoglobulin A antibodies.

BACKGROUND: Immunoglobulin A (IgA)-deficient patients with anti-IgA (Ab) require transfusions using blood components with less than 0.05 mg IgA/dL as they are known to be safe for these patients. Identification of severely IgA-deficient (IgA SD) donors involved preliminary screening by the Ouchterlony double immunodiffusion assay followed by confirmatory testing at the required level of sensitivity for IgA and Ab at an external reference laboratory. Two in vitro particle gel immunoassays (ID-PaGIA IgA deficiency test and anti-IgA test) were also evaluated for their suitability in identifying IgA SD individuals and determining their Ab status. STUDY DESIGN AND METHODS: Samples from 198 donors and 36 patients, subjected to confirmatory testing for IgA SD and Ab over a 2-year period, were also evaluated using the ID-PaGIA kits. RESULTS: DiaMed test sensitivity and specificity for detection of IgA SD in donors was 98% whereas for Ab, test sensitivity was 91% at a specificity of 94%. In patients, sensitivity was 94% for IgA SD and 67% for Ab, both tests at a specificity of 100%. CONCLUSIONS: The ID-PaGIA IgA deficiency test was a sensitive and specific tool for identifying IgA SD donors or patients. Sensitivity of the Ab test was high for donors but reduced for patients and of high specificity in both groups. Further studies with patients are needed to confirm this latter observation. Implementation of these tests would make it possible to supply appropriate products from IgA SD donors to prevent anaphylactic transfusion reactions in patients.

West Nile virus in 2006 and 2007: the Canadian Blood Services' experience.

BACKGROUND: The Canadian blood supply has been screened for West Nile virus (WNV) since 2003. A strategy for targeted individual-donation nucleic acid testing (ID-NAT) was implemented in 2004 to identify potentially infectious donations that may be missed by minipool (MP) testing. In 2007, Canada experienced a larger epidemic than in previous years providing an opportunity to evaluate the ID-NAT triggering algorithm in higher-risk areas. STUDY DESIGN AND METHODS: A specially created database and internal-external communication identified regions for targeted ID-NAT using MP and community triggers. WNV-positive donations identified by ID-NAT were reexamined in MP to assess the efficacy of targeted ID-NAT in identifying potentially infectious donations that may have been missed by MP testing. WNV-positive donation data from 2006 and 2007 were analyzed to examine temporal and geographic trends. A telephone survey about symptoms was carried out after the 2007 season. RESULTS: In total 78 WNV-positive donations were identified (66 true-positives and four false-positives being in 2007). Most positive donations were in the late summer, concentrated in the same western provinces as community cases. Fifty-two donations were identified by ID-NAT and 46% were consistently positive in MP. Of the other 54%, 74% were immunoglobulin (Ig)M- and/or IgG-positive. Fifty-six percent of donors experienced mostly mild symptoms before or after donation (but all said they were well at the time of donation). CONCLUSION: WNV-positive donations correspond geographically with the epidemic. MP testing identifies most potentially infectious donations with a smaller potential benefit from targeted ID-NAT. Mild symptoms are common but may not deter donation.

Screening of Canadian Blood Services donors for severe immunoglobulin A deficiency.

BACKGROUND: Immunoglobulin A (IgA)-deficient patients with antibodies to IgA require transfusions with IgA-deficient blood components to either avoid or reduce the frequency of serious adverse reactions. To supply compatible blood components for these individuals, the Canadian Blood Services (CBS) National Testing Laboratory must initially screen and subsequently identify, after confirmatory testing at the American Red Cross (ARC), donors severely deficient in IgA (<0.05 mg/dL). STUDY DESIGN AND METHODS: The Ouchterlony double immunodiffusion assay was used as an initial screen at CBS to identify IgA-deficient donors (test sensitivity 2-4 mg/dL). Sample aliquots from these donors were then sent to the ARC for confirmatory testing using an enzyme-linked immunosorbent assay method for severe IgA deficiency (<0.05 mg/dL) and a passive hemagglutination assay to detect anti-IgA. RESULTS: From November 2007 to December 2008, of 54,594 samples screened initially at CBS there were 137 samples (0.251%) identified as possibly IgA deficient. Of these 137, there were 100 reports returned from ARC confirming severe IgA deficiency in 65 donors (25 female, 40 male) without detectable anti-IgA and in 35 donors (18 female, 17 male) with anti-IgA. The remaining 37 donors had IgA levels of more than 0.05 mg/dL. CONCLUSION: Results from the ARC confirmed a frequency of 1 in 546 in the CBS' blood donor population for severe IgA deficiency (<0.05 mg/dL), 1 in 840 for those without anti-IgA, and 1 in 1560 for those with antibody. Donors repeatedly confirmed as severely IgA deficient without anti-IgA were considered eligible for the CBS IgA-deficient donor registry program.

Impact of a policy to permit the return of donors repeat-reactive to the Abbott PRISM antibody to hepatitis B core antigen assay.

BACKGROUND: The expected donor loss from recent implementation of antibody to hepatitis B core antigen (anti-HBc) testing in Canada was uncertain but potentially significant based on US experience. To reduce donor loss from false-reactive tests, repeat-reactive donors without other evidence of infection were eligible to return. The aim was to evaluate the impact of anti-HBc testing on donor loss and to evaluate the effectiveness of this policy. STUDY DESIGN AND METHODS: For each donor in the first year of implementation (April 9, 2005-April 8, 2006) repeat-reactive for the presence of anti-HBc only but eligible to return (screening test for hepatitis B surface antigen-negative, plus not reactive to antibody to hepatitis B surface antigen [anti-HBs] and hepatitis B virus [HBV] DNA supplemental tests), 10 matched donors not reactive to the anti-HBc assay were selected. Return rates over 2 years were compared using conditional logistic regression. Testing outcomes were tabulated. RESULTS: Over the first year of testing, 412,236 donors (951,423 donations) were tested for anti-HBc, and 4,489 donors were repeat-reactive (1.3% of first-time donors, 1.0% of repeat donors). Of these 85.6 percent were also reactive for the presence of anti-HBs and/or HBV DNA supplemental tests leaving less than 15 percent eligible to return, of whom 73 percent returned (vs. 90% of controls, p < 0.001). Of the 300 anti-HBc repeat-reactive returning donors, 74 percent were anti-HBc repeat-reactive again (thus permanently deferred), 19 percent were deferred for other reasons versus 14 percent of controls (p < 0.05), and 7 percent (21 donors) did not react and were eligible to continue donating. CONCLUSION: Most donors repeat-reactive for the presence of anti-HBc likely have past exposure to HBV. If eligible, most are willing to return, but likely to test anti-HBc repeat-reactive again.

Hepatitis E Virus Infection in Blood Donors and Risk to Patients in the United States and Canada.

Hepatitis E virus (HEV) is the most common cause of acute hepatitis worldwide including large water-borne outbreaks, zoonotic infections and transfusion transmissions. Several countries have initiated or are considering blood donor screening in response to high HEV-RNA donation prevalence leading to transfusion-transmission risk. Because HEV transmission is more common through food sources, the efficacy of blood donor screening alone may be limited. HEV-nucleic acids in 101 489 blood donations in the United States and Canada were studied. A risk-based decision-making framework was used to evaluate the quantitative risks and cost-benefit of HEV-blood donation screening in Canada comparing three scenarios: no screening, screening blood for all transfused patients or screening blood for only those at greatest risk. HEV-RNA prevalence in the United States was one per 16 908 (95% confidence interval [CI], 1:5786-1:81987), whereas Canadian HEV-RNA prevalence was one per 4615 (95% CI, 1:2579-1:9244). Although 4-fold greater, Canadian HEV-RNA prevalence was not significantly higher than in the United States. Viral loads ranged from 20 to 3080 international units per mL; all successfully typed infections were genotype 3. No HEV-RNA false-positive donations were identified for 100 percent specificity. Without donation screening, heart and lung transplant recipients had the greatest HEV-infection risk (1:366962) versus kidney transplant recipients with the lowest (1:2.8 million) at costs of $225 546 to $561 810 per quality-adjusted life-year (QALY) gained for partial or universal screening, respectively. Higher cost per QALY would be expected in the United States. Thus, HEV prevalence in North America is lower than in countries performing blood donation screening, and if implemented, is projected to be costly under any scenario.

Epidemiology of hepatitis B in Canadian blood donors.

BACKGROUND: The residual risk of hepatitis B is higher than for other markers such as human immunodeficiency virus and hepatitis C virus in nonendemic countries. Evaluating the potential for further risk reduction requires a better understanding of the relationship between donor selection criteria, immigration from endemic countries, and public health vaccination strategies. STUDY DESIGN AND METHODS: Age and sex trends of hepatitis B surface antigen (HBsAg)-positive donors from 1997 to 2006 were analyzed using a Poisson model. All HBsAg-positive donors in 2005/2006 plus four matched control donors for every HBsAg-positive donor who participated were invited to participate in a risk factor interview and predictors of HBsAg positivity identified by logistic regression. A survey of 40,000 donors who did not react for all markers asked about vaccination history and country of birth. RESULTS: Most HBsAg-positive donations were from first-time donors (86%), have been decreasing in donors under the age of 30 (p < 0.01), and were correlated with geographic regions with more donors from higher-prevalence countries (p < 0001). Birth in a higher-prevalence country predicted HBsAg positivity (p < 0.01). Fifty-six percent of donors reported being vaccinated for hepatitis including approximately 80 percent of donors under age 30 who reported being vaccinated as part of regular school programs. CONCLUSION: HBsAg-positive donations are decreasing in donors under age 30, those most frequently vaccinated through provincial vaccination programs. HBsAg-positive donations largely reflect immigration from high-prevalence countries without other deferrable risk factors, mainly chronic cases that will be detected by current testing. Furthermore, risk of incident infections should decrease with increasing vaccination rates in donors, especially the younger cohort now receiving universal vaccination.