Antimicrobial therapy in the management of odontogenic infections: the penicillin-allergic patient.

This retrospective analysis was performed to investigate whether clindamycin remains the preferred antibiotic for penicillin-allergic patients with odontogenic infections. The medical records of 311 patients admitted to the study department with odontogenic infections between 2018 and 2022 and treated with either intravenous amoxicillin-clavulanic acid (Augmentin) or intravenous clindamycin were analyzed. The Augmentin-treated group included 268 patients (86.2%) and the clindamycin-treated group included 43 patients (13.8%). Severity parameters did not differ significantly between the two groups, except for a higher prevalence of abscesses in the clindamycin-treated group (58.1% vs 41.0% in the Augmentin-treated group; P = 0.035). The clindamycin-treated group required a longer duration of intravenous antibiotics (P = 0.001) and had a higher rate of treatment failure (14.0% vs 2.2%; P = 0.002) when compared to the Augmentin-treated group, with a seven-fold increased risk of treatment failure. Moreover, significantly more isolated organisms in the clindamycin-treated group were resistant to clindamycin (P = 0.015); these were all Streptococcus anginosus group. Given the higher risk of treatment failure with clindamycin, it is necessary to choose the antibiotic treatment for penicillin-allergic patients carefully. A detailed history and allergy testing followed by combination therapy is recommended, especially in severe cases.

Intraoperative blood loss and the need for preoperative blood preparations in transgender women undergoing facial feminization surgeries: implications for surgeons.

The aim of this retrospective study was to assess blood loss during facial feminization surgeries and to evaluate blood transfusion requirements. Data from the medical records of all male-to-female transgender patients (transwomen) treated with gender affirming hormones and undergoing facial feminization surgeries were analysed. The total blood loss was calculated based on the haemoglobin balanced method. Twenty transwomen (average age of 25.9 years) were enrolled. Group 1 included 10 transwomen who underwent cranioplasty, genioplasty, and mandibular angles refining, group 2 included six transwomen who underwent cranioplasty and genioplasty, and group 3 included four transwomen who underwent mandibular angles refining and genioplasty. The median calculated blood loss for groups 1, 2, and 3 was 1159.7 ml, 828.5 ml, and 546.2 ml, respectively. The group differences in surgical time, intraoperative fluid amounts, and calculated blood loss volumes were significant. None of the patients required an intraoperative blood transfusion and the hormonal treatment had no effect on the amount of calculated blood loss. Hence, blood loss during facial feminization surgeries is well controlled and does not lead to life-threatening events, precluding the possibility of providing generalized recommendations for preoperative blood transfusion preparations.

Submucosal Fibrotic Bands in Oral Lichen Planus: A Clinico-Pathological Investigation of a Newly Described Phenomenon.

Fibrosis is a recognized complication of chronic inflammatory conditions, which has not yet been described in oral lichen planus. To describe characteristics of submucosal fibrotic bands in oral lichen planus. Prospective study. Patients with biopsy confirmed lichen planus were included. Clinical examination recorded fibrotic bands, mouth opening, vestibular depth loss, gingival recessions adjacent to band, lichen subtypes, areas of affected mucosa, extra-oral manifestations. Patients completed the Chronic Oral Mucosal Disease Questionnaire, with additional questions regarding stiffness, restricted opening, symptom frequency, time from diagnosis of lichen, co-existing medical conditions. 73 patients were included, 14 M, 59 F, age 28-84 (mean 61) years. Buccal fibrous bands were palpated in 22 (30.1%), 13 (59%) were bilateral. Self-reported restricted opening/stiffness were significantly associated with fibrous bands (36% Vs. 11% in controls, p = 0.02). Mouth opening less than 40 mm was recorded in only 2 (9%) with bands, none in controls. Reduced vestibular depth was significantly associated with bands (11 (50%) Vs 3 (6%) in controls, p = 0.0001).Gingival recessions adjacent to bands were recorded in 3 (13.6%). No association was demonstrated between fibrous bands and erosive lesions, extra oral involvement, smoking, age, visual analogue scale, quality of life questionaire and disease duration. Histological evaluation of one case each with and without band and control showed increased mean width of connective tissue. Submucous fibrous band is first described in the present study. It is common in oral lichen planus, may lead to feeling restricted mouth opening, stiffness, loss of vestibular depth and adjacent gingival recession.

Medication-related osteonecrosis of the jaws associated with intravitreal administration of ranibizumab.

Medication-related osteonecrosis of the jaws (MRONJ) is a well-known complication that, in the majority of cases, is related to antiresorptive agents. Numerous articles have described cases of MRONJ in bisphosphonate-naïve patients treated with anti-angiogenic agents administered via various routes. A single case of MRONJ after intravitreal injection of bevacizumab has been reported. We report a case of MRONJ after intravitreal injection of a different anti-angiogenic agent - ranibizumab - for the treatment of neovascular age-related macular degeneration, in a bisphosphonate-naïve patient. Although it may be a rare complication, patients treated with multiple doses of anti-angiogenic agents should be monitored for the possible early diagnosis of MRONJ.

Endoscopic sinus surgery for dental implant displacement into the maxillary sinus-a retrospective clinical study.

The aims of this retrospective clinical study were to present our management protocol for the retrieval of impacted dental implants that have become displaced into the maxillary sinus cavity and to define the role of endoscopic sinus surgery in this setting. All 24 patients (25 implants) who underwent surgical retrieval of dental implants displaced into the maxillary sinus between 2012 and 2019 were included. Data on surgical interventions and complications were collected retrospectively. Eleven patients (46%) had chronic sinusitis associated with the migrated implant. All implants were successfully retrieved via transnasal endoscopic approach alone: 80% via a middle meatal antrostomy and 20% via a combined middle and inferior meatal antrostomy. Five patients required a concomitant transoral approach for oro-antral fistula repair. None required a transoral approach for displaced implant retrieval. All patients healed uneventfully without complications. Transnasal endoscopic sinus surgery via a middle meatal antrostomy or a combined middle and inferior antrostomy is recommended as the primary choice for dental implant retrieval from the maxillary sinus. A transoral approach should be performed simultaneously only for oro-antral fistula repair. This surgical protocol proved to be safe and efficient, and it obviated the need for osteotomies of the anterolateral maxillary wall.

Comparison of the histopathological characteristics of osteomyelitis, medication-related osteonecrosis of the jaw, and osteoradionecrosis.

The purpose of this study was to compare the histopathological parameters of chronic/suppurative osteomyelitis, medication-related osteonecrosis of the jaw (MRONJ), and osteoradionecrosis (ORN), and to examine the hypothesis that distinct histological features can be related to a specific disease, allowing for diagnosis based on microscopic evaluation alone. One hundred and ten samples were reviewed by two examiners in a blinded fashion, and a semi-quantitative histomorphometric analysis was performed. The parameters evaluated included the presence or absence of necrotic bone, inflammation, reactive bone formation, bacteria, and osteoclasts. No statistically significant differences were found between groups for any parameter. Necrotic bone was common to all three diagnoses. Inflammation and reactive bone formation were present in all three diagnoses. The presence of bacteria was a prominent feature in all cases. Osteoclasts were scarce in MRONJ and osteomyelitis, and non-existent in ORN. The results of this study failed to identify distinctive microscopic characteristics in any of the three entities that could be used to differentiate between them. Therefore, it is impossible to reach a specific final diagnosis based on microscopic findings alone. The role of microscopic analysis is to serve as an aid to diagnosis that must be complemented by the patient's history and imaging.

Incidence and clinical characteristics of transfusion-associated circulatory overload using an active surveillance algorithm.

BACKGROUND: The concordance of haemovigilance criteria developed for surveillance of transfusion-associated circulatory overload (TACO) with its clinical diagnosis has not been assessed. In a pilot study to evaluate an electronic screening algorithm, we sought to examine TACO incidence and application of haemovigilance criteria in patients with post-transfusion pulmonary oedema. STUDY DESIGN AND METHODS: From June to September 2014, all transfused adult inpatients at four academic hospitals were screened with an algorithm identifying chest radiographs ordered within 12 h of blood component release. Patients with post-transfusion pulmonary oedema underwent case adjudication by an expert panel. TACO incidence was calculated, and clinical characteristics were compared with other causes of post-transfusion pulmonary oedema. RESULTS: Among 4932 transfused patients, there were 3412 algorithm alerts, 50 cases of TACO and 47 other causes of pulmonary oedema. TACO incidence was 1 case per 100 patients transfused. TACO classification based on two sets of haemovigilance criteria (National Healthcare Safety Network and proposed revised International Society for Blood Transfusion) was concordant with expert panel diagnosis in 57% and 54% of reviewed cases, respectively. Although the majority of clinical parameters did not differentiate expert panel adjudicated TACO from other cases, improved oxygenation within 24 h of transfusion did (P = 0·01). CONCLUSIONS: The incidence of TACO was similar to that observed in prior studies utilizing active surveillance. Case classification by haemovigilance criteria was frequently discordant with clinical diagnoses of TACO in patients with post-transfusion pulmonary oedema. Improvements in oxygenation within 24 h of transfusion merit further evaluation in the diagnosis of TACO.

[One stage combined endoscopic and per-oral buccal fat pad approach for large oro-antral-fistula closure with secondary chronic maxillary sinusitis].

There are numerous surgical approaches for oro-antral-fistula (OAF) closure. Secondary sinus disease is still considered by many experts a relative contra indication for primary closure. To describe a single-stage combined endoscopic sinus surgery and per-oral buccal fat pad (BFP) flap approach for large OAF causing chronic maxillary sinusitis. The records of all the patients with OAF and chronic manifestations of secondary rhinosinusitis that were treated between 2010 and 2013 in our tertiary care medical center were reviewed. The exclusion criteria were: OAF 5 mm, resolved sino-nasal disease, OAF secondary to malignancy, recurrent fistula, medical history that included radiotherapy to the maxillary bone and age <18 years. Each procedure was performed by a team consisting of a rhinologist and a maxillofacial surgeon. The surgical approach included an endoscopic middle antrostomy with maxillary sinus drainage, and a per-oral BFP regional flap for OAF closure. Total OAF closure, complications and need for revision surgeries. Forty-five patients that underwent OAF closure together with sinus surgery using a combined endoscopic sinus surgery (ESS) and BFP flap approach met the inclusion criteria. There were 28 males and 17 females with a mean ± SD age of 53.5 ± 14.9 years (range 22-80 years). The presenting signs and symptoms included purulent rhinorrhea (n = 22, 48.9%), foreign body in sinus (n = 10, 22.2%) nasal congestion (n = 7, 15.5%), halitosis (n = 6, 13.3%) and pain (n = 5, 12.2%). Surgical complications included local pain (n = 2, 4.4%), persistent rhinitis (n = 2, 4.4%) and synechia (n = 1, 2.2%). One patient required revision surgery due, to an unresolved OAF. The OAF of all the other 44 patients (97.8%) was closed after the first procedure and the paranasal sinuses on the treated side were completely recovered. The mean follow-up time for the group was 7.6 ± 4.3 months (7-21 months), and no untoward sequelae or recurrence were reported. Combined, one step, endoscopic Maxillary sinus drainage together with per-oral BFP flap approach is an efficacious surgical approach for safe closure of OAFs that are complicated with secondary chronic maxillary sinusitis.

Platelet transfusion: a clinical practice guideline from the AABB

BACKGROUND: The AABB (formerly, the American Association of Blood Banks) developed this guideline on appropriate use of platelet transfusion in adult patients. METHODS: These guidelines are based on a systematic review of randomized, clinical trials and observational studies (1900 to September 2014) that reported clinical outcomes on patients receiving prophylactic or therapeutic platelet transfusions. An expert panel reviewed the data and developed recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. RECOMMENDATION 1: The AABB recommends that platelets should be transfused prophylactically to reduce the risk for spontaneous bleeding in hospitalized adult patients with therapy-induced hypoproliferative thrombocytopenia. The AABB recommends transfusing hospitalized adult patients with a platelet count of 10 × 109 cells/L or less to reduce the risk for spontaneous bleeding. The AABB recommends transfusing up to a single apheresis unit or equivalent. Greater doses are not more effective, and lower doses equal to one half of a standard apheresis unit are equally effective. (Grade: strong recommendation; moderate-quality evidence). RECOMMENDATION 2: The AABB suggests prophylactic platelet transfusion for patients having elective central venous catheter placement with a platelet count less than 20 × 109 cells/L. (Grade: weak recommendation; low-quality evidence). RECOMMENDATION 3: The AABB suggests prophylactic platelet transfusion for patients having elective diagnostic lumbar puncture with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 4: The AABB suggests prophylactic platelet transfusion for patients having major elective nonneuraxial surgery with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 5: The AABB recommends against routine prophylactic platelet transfusion for patients who are nonthrombocytopenic and have cardiac surgery with cardiopulmonary bypass. The AABB suggests platelet transfusion for patients having bypass who exhibit perioperative bleeding with thrombocytopenia and/or evidence of platelet dysfunction. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 6: The AABB cannot recommend for or against platelet transfusion for patients receiving antiplatelet therapy who have intracranial hemorrhage (traumatic or spontaneous). (Grade: uncertain recommendation; very-low-quality evidence).(AU)

Human neutrophil antibodies in a blood donor population: a lookback study.

BACKGROUND AND OBJECTIVES: Human neutrophil antibodies (HNA) have been associated with severe transfusion-related acute lung injury (TRALI). We identified HNA antibodies in a blood donor population and performed an observational lookback on patients who received products from these donors to determine whether TRALI was associated with these transfusions. MATERIALS AND METHODS: Human neutrophil antibodies were determined in 1171 blood donors (388 non-transfused males, 390 human leucocyte antigen (HLA) antibody-negative females and 393 HLA antibody-positive females) for IgG and IgM antibodies using a flow cytometric assay. Selected positive samples had a monoclonal antibody immobilization of granulocyte antigen (MAIGA) and neutrophil genotyping performed to confirm specificity. Lookback was performed on patients receiving blood from donors with positive samples by extracting recipient data from hospital medical records. An expert panel of three pulmonary critical care physicians reviewed the summarized data and assigned a diagnosis of TRALI, possible TRALI, cannot distinguish between TRALI and TACO, TACO and other. RESULTS: Eight donors had HNA antibodies of which five contributed to this lookback (3-HNA-specific antibodies, 2-HNA non-specific antibodies). Seventy-six blood products were transfused from these donors into individual patients. One patient developed TRALI that was associated with a donor with a non-specific HNA antibody as well as class-I and class-II HLA antibodies. CONCLUSION: The incidence of TRALI in this lookback was low and combined with low frequency of HNA antibodies in the donor population suggests not screening donors for HNA antibodies at this time is acceptable.

Nucleic acid testing (NAT) of organ donors: is the 'best' test the right test? A consensus conference report.

Nucleic acid testing (NAT) for HIV, HBV and HCV shortens the time between infection and detection by available testing. A group of experts was selected to develop recommendations for the use of NAT in the HIV/HBV/HCV screening of potential organ donors. The rapid turnaround times needed for donor testing and the risk of death while awaiting transplantation make organ donor screening different from screening blood-or tissue donors. In donors with no identified risk factors, there is insufficient evidence to recommend routine NAT, as the benefits of NAT may not outweigh the disadvantages of NAT especially when false-positive results can lead to loss of donor organs. For donors with identified behavioral risk factors, NAT should be considered to reduce the risk of transmission and increase organ utilization. Informed consent balancing the risks of donor-derived infection against the risk of remaining on the waiting list should be obtained at the time of candidate listing and again at the time of organ offer. In conclusion, there is insufficient evidence to recommend universal prospective screening of organ donors for HIV, HCV and HBV using current NAT platforms. Further study of viral screening modalities may reduce disease transmission risk without excessive donor loss.

Hepatitis B virus (HBV) DNA screening of blood donations in minipools with the COBAS AmpliScreen HBV test.

BACKGROUND: The risk of hepatitis B virus (HBV) transmission by blood transfusion (estimated at 1 in 63,000-1 in 205,000 units in the United States) exceeds that of hepatitis C virus (HCV) or human immunodeficiency virus (HIV). Reduction of window-period HBV transmissions through detection of HBV DNA-positive units by minipool nucleic acid testing (MP NAT) would be expected to decrease this risk. STUDY DESIGN AND METHODS: A large multicenter study of the COBAS AmpliScreen HBV test (Roche Molecular Systems) was conducted on minipools of 24 blood donation specimens. The yield of HBV DNA-positive, hepatitis B surface antigen (HBsAg)-negative window-period donations was determined relative to current and newly licensed HBsAg assays. Donors with selected HBV DNA, HBsAg, and anti-hepatitis B core antigen (HBc) results were further evaluated. RESULTS: The detection rate of window-period units was 1 in 352,451 (95% confidence interval, 1 in 2,941,176-1 in 97,561). Assay specificity was high (99.9964%). HBV DNA was detected in 84 percent of HBsAg-positive, anti-HBc-positive donations by MP NAT and in 94 percent when individual-donation (ID) NAT was added. HBV DNA was detected in 0.03 percent of HBsAg-negative, anti-HBc-positive donations by MP NAT and in 0.41 percent when ID NAT was added. CONCLUSIONS: Implementation of HBV MP NAT will provide an increment in safety relative to HBV serologic screening, similar to that for HCV and in excess of that for HIV. Our data indicate that the implementation of HBV MP NAT would likely interdict 39 HBV window-period units and prevent 56 cases of transfusion-transmitted HBV infection annually. The current data indicate that HBV MP NAT should not lead to discontinuation of anti-HBc testing but that discontinuation of HBsAg testing with retention of anti-HBc testing may be possible.

The RADAR repository: a resource for studies of infectious agents and their transmissibility by transfusion.

BACKGROUND: An ongoing issue in transfusion medicine is whether newly identified or emerging pathogens can be transmitted by transfusion. One method to study this question is through the use of a contemporary linked donor-recipient repository. STUDY DESIGN AND METHODS: The Retrovirus Epidemiology Donor Study Allogeneic Donor and Recipient (RADAR) repository was established between 2000 and 2003 by seven blood centers and eight collaborating hospitals. Specimens from consented donors were collected, components from their donations were routed to participating hospitals, and recipients of these units gave enrollment and follow-up specimens for long-term storage. The repository was designed to show that zero transmissions to enrolled recipients would indicate with 95 percent confidence that the transfusion transmission rate of an agent with prevalence of 0.05 to 1 percent was lower than 25 percent. RESULTS: The repository contains pre- and posttransfusion specimens from 3,575 cardiac, vascular, and orthopedic surgery patients, linked to 13,201 donation specimens. The mean number of RADAR donation exposures per recipient is 3.85. The distribution of components transfused is 77 percent red cells, 13 percent whole blood-derived platelet concentrates, and 10 percent fresh frozen plasma. A supplementary unlinked donation repository containing 99,906 specimens from 84,339 donors was also established and can be used to evaluate the prevalence of an agent and validate assay(s) performance before accessing the donor-recipient-linked repository. Recipient testing conducted during the establishment of RADAR revealed no transmissions of human immunodeficiency virus, hepatitis C virus, or human T-lymphotropic virus. CONCLUSIONS: RADAR is a contemporary donor-recipient repository that can be accessed to study the transfusion transmissibility of emerging agents.

Detection of West Nile virus RNA and antibody in frozen plasma components from a voluntary market withdrawal during the 2002 peak epidemic.

BACKGROUND: The US West Nile virus (WNV) epidemic in the summer and fall of 2002 included the first documented cases of transfusion-transmitted WNV infection. In December 2002, the FDA supported a voluntary market withdrawal by the blood banking community of frozen blood components collected in WNV high-activity areas. At the time, the prevalence of viremia and serologic markers for WNV in the blood supply was undefined. STUDY DESIGN AND METHODS: In collaboration with America's Blood Centers, 1468 frozen plasma components (of approx. 60,000 frozen units voluntarily withdrawn from the market) were selectively retrieved from the peak epidemic regions and season (June 23, 2002-September 28, 2002). These units were unlinked, subaliquoted, and tested by WNV enzyme immunoassays (EIAs; Focus Technologies and Abbott Laboratories) and nucleic acid amplification tests (NATs; Gen-Probe Inc. and Roche Molecular Systems). RESULTS: Of the 1468 EIA results from Abbott and Focus, 7 were anti-immunoglobulin M (IgM)- and anti-immunoglobulin G (IgG)-reactive by both assays, 8 and 1 were IgM-only-reactive, and 8 and 23 were IgG-only-reactive, respectively. NAT by Gen-Probe and Roche Molecular Systems yielded one RNA-positive, antibody-negative unit containing approximately 440 RNA copies per mL. An additional 10-fold replicate NAT testing by Gen-Probe on 14 of 15 IgM-reactive specimens yielded 2 additional IgM- and IgG-reactive units with low-level viremia (i.e., 7/10 and 2/10 replicates tested reactive). CONCLUSION: The prevalence of acute (RNA-positive) and recent (IgM-seroreactive) WNV infections indicates that transfusion risk in high-risk areas could have been considerable and that voluntary market withdrawal of frozen components likely averted some WNV transfusion transmissions. The existence of very-low-level viremic units raises concerns, because WNV minipool NAT screening will miss such units and individual NAT may not completely correct this situation.

Analytical and clinical sensitivity of West Nile virus RNA screening and supplemental assays available in 2003.

BACKGROUND: Transfusion-transmitted West Nile virus (WNV) infections were first reported in 2002, which led to rapid development of investigational nucleic acid amplification tests (NAT). A study was conducted to evaluate sensitivities of WNV screening and supplemental NAT assays first employed in 2003. STUDY DESIGN AND METHODS: Twenty-five member-coded panels were distributed to NAT assay manufacturers. Panels included five pedigreed WNV standards (1, 3, 10, 30, and 100 copies/mL), 15 or 16 donor units with very-low-level viremia identified through 2003 screening, and four or five negative control samples. Samples were tested neat in 10 replicates by all assays; for NAT screening assays, 10 replicates were also performed on dilutions consistent with minipool (MP)-NAT. The viral load distribution for 142 MP-NAT yield donations was characterized, relative to the analytical sensitivity of MP-NAT systems. RESULTS: Analytical sensitivities (50% limits of detection [LoD] based on Poisson model of detection of WNV standards) for screening NAT assays ranged from 3.4 to 29 copies per mL; when diluted consistent with MP pool sizes, the 50 percent LoD of screening NAT assays was reduced to 43 to 309 copies per mL. Analytical sensitivity of supplemental assays ranged from 1.5 to 7.7 copies per mL (50% LoD). Detection of RNA in donor units varied consistent with analytical LoD of assays. Detection of low-level viremia after MP dilutions was particularly compromised for seropositive units, probably reflecting lower viral loads in the postseroconversion phase. Based on the viral load distribution of MP-NAT yield donations (median, 3519 copies/mL; range, < 50-690,000), 13 to 24 percent of units had viral loads below the 50 percent LoD of screening NAT assays run in MP-NAT format. CONCLUSION: WNV screening and supplemental assays had generally excellent analytical sensitivity, comparable to human immunodeficiency virus-1 and hepatitis C virus NAT assays. The presence of low-level viremic units during epidemic periods and the impact of MP dilutions on sensitivity, however, suggest the need for further improvements in sensitivity as well as a role for targeted individual-donation NAT in epidemic regions.

Comparison of demographic and donation profiles and transfusion-transmissible disease markers and risk rates in previously transfused and nontransfused blood donors.

BACKGROUND: Increasing concern about transfusion transmission of variant Creutzfeldt-Jakob disease has resulted in indefinite deferral of transfused donors in France and the UK. Little is known, however, about the impact of indefinite deferral of transfused donors on blood safety and availability in the US. STUDY DESIGN AND METHODS: Data were collected on allogeneic donations at five US blood centers during 1991 through 2000. Donation characteristics, prevalence, and incidence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) were compared between transfused and nontransfused donors. Unreported deferrable risk (UDR) and reasons to donate were evaluated with data from a mail survey. RESULTS: Transfusion history was reported by 4.2 percent of donors. Prevalence and incidence of HIV and HBV were comparable between transfused and nontransfused donors. Although HCV incidence was similar in both groups, HCV prevalence was nearly three times higher in transfused than in nontransfused first-time donors. UDR and reasons to donate were similar in the two groups, except transfused donors were less likely to donate for screening test results (odds ratio, 0.5; 95% confidence interval, 0.3-0.8). CONCLUSION: Transfused and nontransfused donors had similar viral incidence and comparable UDR, suggesting that indefinite deferral of transfused donors would unlikely improve blood safety. Until more is known about the prevalence and transfusion transmissibility of emerging agents, indefinite deferral of previously transfused donors in the US does not appear warranted.