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.

Rapid evaluation of risk of white particulate matter in blood components by a statewide survey of transfusion reactions.

BACKGROUND: In January 2003, white particulate matter (WPM) was detected in blood components. Because the composition and cause of WPM was not understood at that time, there was uncertainty about whether WPM could endanger patient safety. To investigate possible adverse patient events associated with WPM, transfusion reaction rates were examined. STUDY DESIGN AND METHODS: A questionnaire was distributed to Georgia medical centers. Data collected included the number of components transfused and reported adverse reactions by component type from January 2002 through January 2003, and date, reaction type, and blood supplier for events in January 2003. RESULTS: Of 124 transfusion services contacted, 108 (87%) responded. During the survey period, there were 1213 reported transfusion reactions and 528,412 units transfused, or 2.3 reactions per 1000 units transfused; for RBCs, 2.4 (range, 1.8-3.1); plasma, 1.5 (range, 0.6-3.5); and PLTs, 3.4 (2.1-5.4) per 1000 units. Transfusion reaction rates by component for January 2003 did not differ significantly from the rate for January 2002 or for the calendar year. The 86 reported reactions that occurred in January 2003 were attributed to bacterial contamination (n = 2, 2.3%), other febrile nonhemolytic (n = 49, 57.0%), allergic (n = 14, 16.3%), and "other" reactions (n = 21, 24.4%); the proportions of reaction types did not differ significantly during the month. CONCLUSION: No overall changes in reported adverse reaction rates occurred over the survey period or in the proportion of reaction types during January 2003 when WPM was detected. Statewide surveillance of transfusion reactions could be useful to evaluate potential threats to blood safety.

Simian foamy virus infection in a blood donor.

BACKGROUND: Infections with simian foamy virus (SFV) are widely prevalent in nonhuman primates. SFV infection was confirmed in a worker, occupationally exposed to nonhuman primates, who donated blood after the retrospectively documented date of infection. Human-to-human transmission of SFV through transfusion and its pathogenicity have not been studied. STUDY DESIGN AND METHODS: Recipients of blood from this donor were identified and blood samples from such recipients were tested for SFV infection by Western blot and PCR assay. RESULTS: One recipient of RBCs and another recipient of FFP had died; retroviral infections were not implicated. One platelet recipient could not be tested. Recipients of RBCs (two), a WBC-reduced RBC unit (one), and a platelet unit (one) tested SFV-negative 19 months to 7 years after transfusion. Tested recipients had transfusions 3 to 35 days after blood donation. Samples of one lot of albumin and three lots of plasma protein fraction (manufactured from recovered plasma from two donations) tested negative both for antibodies and for viral RNA. CONCLUSION: SFV transmission through transfusion was not identified among four recipients of cellular blood components from one SFV-infected donor. Derivatives containing plasma from that donor tested negative for SFV.

Emerging infectious disease issues in blood safety.

Improvements in donor screening and testing and viral inactivation of plasma derivatives together have resulted in substantial declines in transfusion-transmitted infections over the last two decades. Most recently, nucleic acid testing techniques have been developed to screen blood and plasma donations for evidence of very recent viral infections that could be missed by conventional serologic tests. Nonetheless, the blood supply remains vulnerable to new and reemerging infections. In recent years, numerous infectious agents found worldwide have been identified as potential threats to the blood supply. Several newly discovered hepatitis viruses and agents of transmissible spongiform encephalopathies present unique challenges in assessing possible risks they may pose to the safety of blood and plasma products.

Risk and management of blood-borne infections in health care workers.

Exposure to blood-borne pathogens poses a serious risk to health care workers (HCWs). We review the risk and management of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infections in HCWs and also discuss current methods for preventing exposures and recommendations for postexposure prophylaxis. In the health care setting, blood-borne pathogen transmission occurs predominantly by percutaneous or mucosal exposure of workers to the blood or body fluids of infected patients. Prospective studies of HCWs have estimated that the average risk for HIV transmission after a percutaneous exposure is approximately 0.3%, the risk of HBV transmission is 6 to 30%, and the risk of HCV transmission is approximately 1.8%. To minimize the risk of blood-borne pathogen transmission from HCWs to patients, all HCWs should adhere to standard precautions, including the appropriate use of hand washing, protective barriers, and care in the use and disposal of needles and other sharp instruments. Employers should have in place a system that includes written protocols for prompt reporting, evaluation, counseling, treatment, and follow-up of occupational exposures that may place a worker at risk of blood-borne pathogen infection. A sustained commitment to the occupational health of all HCWs will ensure maximum protection for HCWs and patients and the availability of optimal medical care for all who need it.

Failure of routine HIV-1 tests in a case involving transmission with preseroconversion blood components during the infectious window period.

CONTEXT: Current screening practices for blood donations have been successful in reducing human immunodeficiency virus (HIV) transmission through receipt of contaminated blood products. However, HIV-infected blood donations made prior to seroconversion and before high levels of viral replication occur could test negative using both serologic antigen and antibody tests. Testing based on nucleic acid amplification (NAT) is being implemented to screen for HIV-infected blood donated during this period, yet the issue of single vs minipool donation screening remains unresolved. OBJECTIVES: To determine HIV-1 genetic linkage between virus in 2 HIV-1-infected recipients of blood components and virus in the donor, who was HIV antigen and antibody negative at the time of donation; to screen the blood donor's plasma with HIV NAT assays, including those currently proposed for use in US blood donation screening. DESIGN AND SETTING: Case study conducted in October 1997 involving the Communicable Disease Centre, Singapore General Hospital, and the Singapore Blood Transfusion Service, Singapore. SUBJECTS: The blood donor and the 2 recipients of donor platelets and red blood cells. MAIN OUTCOME MEASURES: Genetic analysis of the HIV-1 p17 coding region of gag and the C2V5 region of env to determine the genetic relatedness of virus from the donor and recipients; reactivity in quantitative and qualitative assays, and reactivity in donor screening HIV NAT assays in single donation and minipool screening contexts. RESULTS: Direct DNA sequencing demonstrated identical HIV-1 subtype E viral sequences in the donor and recipients. Based on comparisons of a qualitative and quantitative assay for HIV-1 RNA levels, a low level of viremia (range, 5-39 copies/mL in plasma) was estimated to be in the donor's undiluted blood at the time of donation. Additional testing using donor-screening NAT assays showed consistent detection of HIV RNA in the undiluted donor plasma whereas detection was inconsistent at the 1:16 and 1:24 dilution levels currently used in minipool screening of blood donations in the United States. CONCLUSIONS: Transmission of HIV from a blood donor to a platelet recipient and a red blood cell recipient occurred in the preseroconversion infectious window period. The viral load in the implicated donation was estimated to be less than 40 copies/mL of plasma. Current US minipool HIV NAT screening protocols may not be sufficiently sensitive to detect all infectious window-period donations. JAMA. 2000;284:210-214

The nature and frequency of blood contacts among home healthcare workers.

OBJECTIVE: To estimate the frequency of, and assess risk factors for, percutaneous, mucous membrane, and cutaneous blood contacts sustained by healthcare workers (HCWs) during the delivery of infusion therapy and the performance of procedures involving sharp instruments in the home setting. DESIGN: Prospective surveillance of percutaneous, mucous membrane, and cutaneous blood contacts. SETTING: Eleven home healthcare agencies in the United States and Canada from August 1996 through June 1997. PARTICIPANTS: HCWs who provided home infusion therapy or performed procedures using hollow-bore needles and other sharp instruments in the home setting. METHODS: Each participating worker recorded information about the procedures performed and blood contacts experienced during each of his or her home visits for a 2- to 4-week period using standard questionnaires. HCWs also completed questionnaires regarding job duties, reporting of previous occupational blood contacts, and their use of protective barriers in the home setting. RESULTS: Participating HCWs provided information about 33,606 home visits. A total of 19,164 procedures were performed during 14,744 procedure visits. Fifty-three blood contacts occurred during these visits, for a blood-contact rate of 2.8 blood contacts per 1,000 procedures and 0.6 percutaneous injuries per 1,000 procedures with needles or lancets. Gloves were worn for 52%, masks for 5%, gowns for 3%, and protective glasses or goggles for 2% of all procedure visits. HCWs used barriers for 53% of visits during which at least 1 procedure was performed and for 27% of other visits. CONCLUSIONS: HCWs involved in home health care are at risk for blood contact. Infection control barrier use was low in our study. The majority of skin contacts could have been prevented by glove use.

Surveillance for bloodborne infections.

At the close of the 20th century, the blood supply in the U.S. is among the safest in the world. Multifaceted and overlapping strategies that include comprehensive donor history-taking and screening (soon to include nucleic acid testing for HCV and HIV), and viral inactivation of plasma derivatives have resulted in significant declines in transfusion-transmitted infections. Nonetheless, we and our blood supply remain vulnerable to new or re-emerging infections as a consequence of changes in human behavior and demographics, improvements in technology and industry, economic development and land use, and microbial change. The second phase of CDC's strategic plan to improve our national capacity against emerging infectious diseases targets diseases transmitted through blood and blood products as one of its nine special focus areas. One of our mainstays against emerging threats must include surveillance, integrated with a multi-disciplinary approach that includes epidemiology and laboratory sciences. Enhanced surveillance can play an important role in helping to ensure the continued safety of blood and plasma products.

Surveillance for transfusion-transmitted viral infections in the United States.

Surveillance is part of a multi-faceted programme to monitor the safety of the U. S. blood supply. The Centers for Disease Control and Prevention administers several national surveillance programmes, including pathogen- and disease-specific systems (e.g. human immunodeficiency virus, hepatitis) and programmes that focus on donors and recipients of blood and plasma products (e.g. persons with haemophilia). Data collected in these systems can be used to monitor temporal and epidemiological trends, identify risk factors for infection, facilitate identification and investigation of potential outbreaks, and evaluate intervention and prevention strategies.

Blood safety.

Since blood is a biologic product, it is unlikely that the risk for transfusion-transmitted infection will ever be reduced to zero. The approach to emerging infections associated with transfusion of blood and blood products includes assessing the transmissibility of the agent by this route; developing effective prevention strategies, including screening tests and donor deferral policies; improving viral and bacterial inactivation procedures; and surveillance for known, as well as emerging and poorly characterized, transfusion-transmitted agents. Vigilance is needed to help ensure proper balance between safety and the availability of blood. Finally, vigilance needs to extend to the developing world, where the basic elements to reduce transfusion-transmitted infections and systems of disease surveillance are often not available.

Use of the hepatitis-B vaccine and infection with hepatitis B and C among orthopaedic surgeons. The American Academy of Orthopaedic Surgeons Serosurvey Study Committee.

We used a questionnaire, with a guarantee of anonymity to the respondents, and conducted serological testing of 3411 attendees at the 1991 Annual Meeting of The American Academy of Orthopaedic Surgeons to evaluate the prevalences of infection with the hepatitis-B and C viruses and the use of the hepatitis-B vaccine among orthopaedic surgeons. There was evidence of infection with hepatitis B in 410 (13 per cent) of 3239 participants who had reported having no non-occupational risk factors; 2103 (65 per cent) reported that they had been immunized with the hepatitis-B vaccine. Of 3262 participants who reported having no non-occupational risk factors and who were evaluated for infection with hepatitis C, twenty-seven (less than 1 per cent) tested positive for the antibody to the hepatitis-C virus. The prevalence of previous infection with hepatitis B increased with increasing age; four (3 per cent) of 136 surgeons who were twenty to twenty-nine years old had evidence of infection, whereas ninety-six (27 per cent) of 360 surgeons who were sixty years old or more had evidence of infection. The prevalence of infection with hepatitis C also increased with increasing age; none of 135 surgeons who were twenty to twenty-nine years old had evidence of infection, and five (1 per cent) of 360 surgeons who were sixty years old or more had evidence of the virus. The prevalence of vaccination decreased steadily with age: 123 (90 per cent) of 136 surgeons who were twenty to twenty-nine years old reported that they had received the hepatitis-B vaccine, whereas 127 (35 per cent) of 360 surgeons who were sixty years old or more reported that they had received the vaccine. The prevalence of infection with hepatitis B or hepatitis C was not associated with the measured indices of exposure to the blood of patients (the number of cutaneous or mucosal contacts with blood that had occurred within the previous month or the number of percutaneous injuries that had occurred within the previous month or year, as recalled by the participants). In conclusion, the prevalence of immunization with the hepatitis-B vaccine was high among the orthopaedic surgeons studied. Although the prevalence of infection with the hepatitis-C virus was several times greater in the current investigation than has been reported in studies of blood donors in the United States, infection with this virus was not associated with the indices of occupational exposure to blood measured in this study.

Skin and mucous membrane contacts with blood during surgical procedures: risk and prevention.

OBJECTIVE: To study the epidemiology and preventability of blood contact with skin and mucous membranes during surgical procedures. DESIGN: Observers present at 1,382 surgical procedures recorded information about the procedure, the personnel present, and the contacts that occurred. SETTING: Four US teaching hospitals during 1990. PARTICIPANTS: Operating room personnel in five surgical specialties. MAIN OUTCOME MEASURES: Numbers and circumstances of contact between the patient's blood (or other infective fluids) and surgical personnel's mucous membranes (mucous membrane contacts) or skin (skin contacts, excluding percutaneous injuries). RESULTS: A total of 1,069 skin (including 620 hand, 258 body, and 172 face) and 32 mucous membrane (all affecting eyes) contacts were observed. Surgeons sustained most contacts (19% had > or = 1 skin contact and 0.5% had > or = 1 mucous membrane-eye contact). Hand contacts were 72% lower among surgeons who double gloved, and face contacts were prevented reliably by face shields. Mucous membrane-eye contacts were significantly less frequent in surgeons wearing eyeglasses and were absent in surgeons wearing goggles or face shields. Among surgeons, risk factors for skin contact depended on the area of contact: hand contacts were associated most closely with procedure duration (adjusted odds ratio [OR], 9.4; > or = 4 versus < 1 hour); body contacts (arms, legs, and torso) with estimated blood losses (adjusted OR, 8.4; > or = 1,000 versus < 100 mL); and face contacts, with orthopedic service (adjusted OR, 7.5 compared with general surgery). CONCLUSION: Skin and mucous membrane contacts are preventable by appropriate barrier precautions, yet occur commonly during surgery. Surgeons who perform procedures similar to those included in this study should strongly consider double gloving, changing gloves routinely during surgery, or both.

Occupational risk of infection with human immunodeficiency virus.

The risk of HIV infection in surgical settings is a composite of overlapping risks related to the local prevalence of HIV, the route of exposure to HIV-infected blood, and the susceptibility of the worker. Studies continue to suggest that the risk of blood contact, including percutaneous injuries, remains appreciable. Prevention of such exposures in the operating and delivery room by adoption of safer instruments, work practices, and techniques and by the consistent use of appropriate personnel protective equipment must be viewed as a priority.

Preventing bloodborne pathogen transmission from health-care workers to patients. The CDC perspective.

The development of recommendations to manage the risk of bloodborne pathogen transmission from health-care workers to patients during invasive procedures has been difficult, primarily because of the limitations of available scientific data. Ultimately, both health-care workers and patients will be protected best by compliance with infection control precautions and by development of new instruments, protective equipment, and techniques that reduce the likelihood of intraoperative blood exposure without adversely affecting patient care.

Percutaneous injuries in dentistry: an observational study.

The authors conducted an observational study of the frequency and circumstances of percutaneous injuries among dental residents. Their findings suggest that most percutaneous injuries sustained by these dental residents occurred extraorally and were associated with denture impression procedures. Some injuries may be preventable with changes in techniques or instrument design.

Investigations of patients of health care workers infected with HIV. The Centers for Disease Control and Prevention database.

OBJECTIVE: To assess the risk for transmission of the human immunodeficiency virus (HIV) from an infected health care worker to patients. DESIGN: Survey of investigators from health departments, hospitals, and other agencies who had elected to notify patients who had received care from health care workers infected with HIV. MEASUREMENTS: Information was collected about infected health care workers, their work practices, their patients' HIV test results, procedures that they did on those of their patients who were tested for HIV, and patient notification procedures. RESULTS: As of 1 January 1995, information about investigations of 64 health care workers infected with HIV was reported to the Centers for Disease Control and Prevention; HIV test results were available for approximately 22,171 patients of 51 of the 64 health care workers. For 37 of the 51 workers, no seropositive patients were reported among 13,063 patients tested for HIV. For the remaining 14 health care workers, 113 seropositive patients were reported among 9108 patients. Epidemiologic and laboratory follow-up did not show any health care worker to have been a source of HIV for any of the patients tested. CONCLUSION: Despite limitations, these data are consistent with previous assessments that state that the risk for transmission of HIV from a health care worker to a patient is very small. These data also support current recommendations that state that retrospective patient notification need not be done routinely.

Human immunodeficiency virus infection among health care workers who donate blood.

OBJECTIVE: To estimate the prevalence of human immunodeficiency virus (HIV) infection among health care workers who donate blood. DESIGN: Point prevalence survey of blood donors. SETTING: 20 U.S. blood centers that participate in an ongoing interview study of HIV-seropositive blood donors. MEASUREMENTS: Prevalence rates for HIV in persons who reported being health care workers were measured directly for 6 of the 20 blood centers. For the other 14 centers, we derived the numerator from the interview study in the same manner used for the 6 centers; we estimated the denominator using blood collection logs at those centers and extrapolations from the survey completed at the 6 blood centers. RESULTS: Between March 1990 and August 1991, 8519 health care workers donated blood at 6 hospitals and other medical facilities. Three persons were HIV seropositive: Two reported being health care workers and having nonoccupational risk factors for HIV infection; the occupation and other possible risk factors of the third seropositive donor could not be determined. Therefore, the highest overall prevalence of HIV infection among health care worker donors at these 6 centers was 0.04% (3 of 8519; upper limit of 95% CI, 0.1%). We estimated that during the same period, approximately 36,329 health care workers were tested for HIV at all 20 centers. Twenty-seven persons infected with HIV who donated at hospitals were identified; 7 did not return for interviews, so their health care occupations could not be verified. Thus, the highest estimated overall prevalence of HIV infection among health care worker donors at the 20 centers was 0.07% (27 of 36,329; upper limit of CI, 0.1%). Of the 20 known health care worker donors, 11 reported nonoccupational risks for HIV infection; 3 of the remaining 9 health care workers described occupational blood exposures that could have resulted in transmission of HIV. CONCLUSIONS: Blood donors can serve as a sentinel cohort when evaluating the risk for occupationally acquired HIV infection. These findings suggest that among the many health care worker donors in this study, HIV infection attributable to occupational exposure was uncommon.

A survey of occupational blood contact and HIV infection among orthopedic surgeons. The American Academy of Orthopaedic Surgeons Serosurvey Study Committee.

OBJECTIVE: To study the seroprevalence of human immunodeficiency virus (HIV) among orthopedic surgeons, and correlate the results with occupational and nonoccupational risk factors. Orthopedic surgeons are one of several groups of health care workers at risk for occupationally acquired HIV infection; however, few HIV seroprevalence studies in health care workers, and none in surgeons, have been performed to assist in estimating the extent of occupational risk. DESIGN: A voluntary, anonymous HIV serosurvey at an annual meeting. To assess the representativeness of participants, a mail survey of orthopedic surgeons was conducted 5 months prior to the annual meeting. SETTING: The 1991 annual meeting of the American Academy of Orthopaedic Surgeons held in Anaheim, Calif. PARTICIPANTS: United States or Canadian orthopedic surgeons in training, in practice, or retired from practice who attended the annual meeting. MAIN OUTCOME MEASURES: Participants' HIV serostatus and reporting of occupational and nonoccupational risk factors for HIV infection. RESULTS: Of 7147 eligible orthopedists at the annual meeting, 3420 (47.9%) participated. Compared with the 10,411 orthopedic surgeons responding to the mail survey, serosurvey participants had at least as many opportunities for occupational contact with blood and with HIV-infected patients. Among participants, 87.4% reported a blood-skin contact and 39.2% reported a percutaneous blood contact in the previous month. Among 3267 participants without reported nonoccupational risk factors for HIV infection, none was positive for HIV antibody (0%; upper limit of the 95% confidence interval [CI] = 0.09%); among 108 participants with reported nonoccupational HIV risk factors, two were positive for HIV antibody (1.9%; upper limit of the 95% CI = 5.7%). CONCLUSION: Although these findings may not be generalizable to all orthopedic surgeons, we found no evidence of HIV infection among serosurvey participants without nonoccupational risk factors. The high rates of self-reported blood contact underscore the importance of compliance with infection control precautions and of development of new techniques and equipment to minimize the risk of exposures to blood during surgical procedures.

Percutaneous injuries during surgical procedures.

OBJECTIVE: To study the numbers and circumstances of percutaneous injuries (eg, needle sticks, cuts) that occur during surgical procedures. Surgical personnel risk infection with blood-borne pathogens from percutaneous injuries; some injuries might also place patients at risk by exposing them to a health care worker's blood. DESIGN: Observers present at 1382 surgical procedures recorded information about the procedure, the personnel present, and percutaneous injuries that occurred. SETTING: Four US teaching hospitals during 1990. PARTICIPANTS: Operating room personnel in five surgical specialties. MAIN OUTCOME MEASURES: Numbers and circumstances of percutaneous injuries among surgical personnel and instances in which surgical instruments that had injured a worker recontacted the patient's surgical wound. RESULTS: Ninety-nine injuries occurred during 95 (6.9%) of the 1382 procedures. Seventy-six injuries (77%) were caused by suture needles and affected the nondominant hand (62 injuries [63%]), especially the distal forefinger. The risk of injury adjusted for confounding variables by logistic regression was higher during vaginal hysterectomy (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.6 to 7.5) and lower during certain orthopedic procedures (OR, 0.2; CI, 0.1 to 0.7) than during 11 other types of procedures (reference group; OR, 1.0). Use of fingers rather than an instrument to hold the tissue being sutured was associated with 35 injuries (35%). Eighty-eight injuries (89%) were sustained by resident or attending surgeons; in 28 (32%) of the 88 injuries in surgeons, the sharp object that caused the injury recontacted the patient. CONCLUSION: Percutaneous injuries occur regularly during surgery, placing surgical personnel and, to a lesser extent, patients at risk for infection with blood-borne pathogens. Many such injuries may be preventable with changes in devices, techniques, or protective equipment; all such measures require careful evaluation to determine their efficacy in reducing injury and their effect on patient care.