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In this study involving 3.7 million blood donors, nucleic acid testing identified 9 donors with HBV infection who were not identified by routine serologic testing. The single triplex assay also identified 2 donors with HIV and 15 with HCV. The transfusion of blood containing hepatitis B surface antigen (HBsAg) is associated with post-transfusion infection with hepatitis B virus (HBV). Blood that is free of HBsAg but has high-titer antibodies against hepatitis B core antigen (anti-HBc) in the absence of antibodies against hepatitis B surface antigen (anti-HBs) can also transmit HBV infection. 1 , 2 In 1986, screening for anti-HBc was implemented in the United States to reduce HBV transmission and as a surrogate marker for non-A, non-B hepatitis (i.e., hepatitis C virus [HCV]). 3 , 4 However, a small proportion of donors with anti-HBc in the absence of HBsAg have circulating HBV DNA . . .

We evaluated antibodies to the nucleocapsid protein of SARS-CoV-2 in a large cohort of blood donors in the United States who were recently infected with the virus. Antibodies to the nucleocapsid protein of SARS-CoV-2 indicate previous infection but are subject to waning, potentially affecting epidemiologic studies. We longitudinally evaluated a cohort of 19,323 blood donors who had evidence of recent infection by using a widely available serologic test to determine the dynamics of such waning. We analyzed overall signal-to-cutoff values for 48,330 donations (average 2.5 donations/person) that had an average observation period of 102 days. The observed peak signal-to-cutoff value varied widely, but the waning rate was consistent across the range, with a half-life of 122 days. Within the cohort, only 0.75% of persons became seronegative. Factors predictive of higher peak values and longer time to seroreversion included increasing age, male sex, higher body mass index, and non-Caucasian race.

Nucleic acid testing (NAT) of blood donors provides opportunities for identifying West Nile virus (WNV)-infected persons before symptoms develop and for characterizing subsequent illness. From June 2003 through 2008, the American Red Cross performed follow-up interviews with and additional laboratory testing for 1436 donors whose donations had initial test results that were reactive for WNV RNA; 821 of the donors were subsequently confirmed to have WNV infection, and the remainder were unconfirmed or determined to have false-positive results. Symptoms attributed to WNV infection were determined by comparing symptom frequency among 576 donors identified with early WNV infection (immunoglobulin M antibody negative) and those with unconfirmed infection. We estimate that 26% of WNV-infected persons become symptomatic, defined by the presence of at least 3 of 8 indicator symptoms. Nearly one-half of symptomatic persons sought medical care; only 5% received a diagnosis of WNV infection. Female subjects and persons with higher viral loads detected in the index donation were more likely than other subjects to develop symptoms.

Since 1999, nucleic acid–amplification testing has been used in the United States to identify units of blood from donors with viremia in the window period before seroconversion. This approach identifies approximately 1 unit infected with human immunodeficiency virus type 1 (HIV-1) among 3.1 million units screened and 1 infected with hepatitis C virus (HCV) among 230,000 units screened. Nucleic acid–amplification testing prevents about 5 cases of transfusion-transmitted HIV-1 infection and 56 of HCV infection per year. Screening of potential blood donors has historically relied on the use of immunoassays to detect viral antibodies or antigens. In 1999, new screening methods involving nucleic acid amplification to detect human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) RNA were implemented in the United States under an investigational new drug protocol approved by the Food and Drug Administration (FDA). 1 – 3 This new technique was used to test multiple samples in small pools, referred to as “minipools.” The decision to implement this technique was based on its ability to identify HIV-1– and HCV-infected donors early in the infectious . . .

Babesia microti is a leading cause of blood transfusion–associated infection in the United States. Investigators from the American Red Cross present data establishing a potential donor-screening test approach to decrease this risk. Babesia microti is an intraerythrocytic parasite that causes babesiosis. 1 The severity of babesia infection ranges from asymptomatic, most commonly in healthy persons, to fatal, most frequently in persons older than 50 years of age, those who have no spleen (or no functional spleen), and those who are immunocompromised. 2 In the United States, B. microti is transmitted to humans primarily by means of the bite of Ixodes scapularis (also called the deer tick). 3 Babesiosis became a nationally notifiable disease (as defined by the Centers for Disease Control and Prevention [CDC]) in 2011 and was reportable (i.e., reportable to the state, which . . .

With the emergence and rapid dissemination of Zika virus, efforts to protect the U.S. blood supply were developed on both the diagnostic-test and implementation fronts. Over a 15-month period in 2016 and 2017, the results of testing more than 4 million donations were assessed.

In common with other developed countries, the United States has placed a great deal of emphasis on blood safety. As a result of careful donor selection and the use of advanced tests, including nucleic acid testing (NAT), the risk of transmission of human immunodeficiency virus and hepatitis C virus has been reduced to about 1 in 1.5 million donations. NAT for hepatitis B virus has not been introduced, but nevertheless the risk is low. Attention recently has been focused on emerging infections. NAT for West Nile virus was implemented within 6 to 8 months of recognition of the need to prevent transfusion transmission of this newly introduced virus. Approximately 1000 potentially infectious donations were identified and removed from the blood supply during the 2003 season. Other emerging infections attracting attention include Chagas' disease, babesiosis, malaria, and variant Creutzfeldt-Jakob disease.

Four key measures help keep the use of blood safe. First, all who prescribe blood should try to limit the frequency of homologous transfusion by responding only to patients' physiologic needs and by using alternatives such as autologous transfusion and intraoperative blood salvage. Second, the selection of safe donors provides the greatest safety. For example, the current detection rate for human immunodeficiency virus (HIV) infection among active blood donors in the United States is between 5 and 10 confirmed positive results per 100,000 — that is, 1/40 to 1/80 of the rate anticipated in a random sample of the population, . . .

Abstract Background The first coronavirus disease 2019 (COVID-19) case in the United States was recognized on 19 January 2020, but the time of introduction of the virus into the United States is unknown. An existing sample cohort was examined for serologic evidence of early severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Methods A repository of 46 120 samples from healthy routine blood donors, representing 46 states and the District of Columbia, was tested for total antibodies to SARS-CoV-2 nucleocapsid (anti-N) using a commercial test. All reactive samples were further tested using an experimental receptor-binding domain (RBD)–specific immunoglobulin G (IgG) enzyme-linked immunosorbent assay. Further testing was also conducted for anti-spike (anti-S) antibodies by commercial tests, experimental anti-S immunologic blocking, and for antibodies to the 4 human cold coronaviruses. Results Anti-N reactivity was observed in 92 tested samples (0.2%), 91 of which had adequate volume for further testing; of these, 55 were confirmed positive by anti-RBD. None of these reactive findings were attributable to the other human coronaviruses tested. The confirmed-positive frequency increased over time paralleling patterns observed for COVID-19 cases reported in the United States (in contrast to stable patterns over time for the cold coronaviruses). Nine confirmed positive samples (0.07%) were identified among the 13 364 donations collected between 13 December 2019 and 22 January 2020. None of these early confirmed-positive samples were reactive by commercial anti-S tests suggesting very recent infection. Conclusions The samples tested in this study were broadly representative of the United States, and all were from individuals who had successfully donated blood. The antibody-reactive results of this study suggest that SARS-CoV-2 was likely present in the United States before 19 January 2020. SARS-CoV-2 infections in the US likely occurred before clinical COVID-19 disease cases. SARS-CoV-2 anti-nucleocapsid reactivity was low during the first 3 months (December 2019–March 2020), increased 10-fold in the following 3 months, and unrelated to the common cold coronaviruses.

Over the past few decades, our optimism — or perhaps hubris — that infectious disease had been conquered has been overturned so completely that emerging infections are now a new discipline, complete with their own journal. Even in the past year, severe acute respiratory syndrome, an entirely new disease of humans, has emerged, and monkeypox, a zoonosis, has appeared for the first time in the Americas. In 1999, the first cases of West Nile virus disease were recognized in New York, and the epidemic has since expanded, infecting about 400,000 Americans (and countless birds, mammals, and even some reptiles) in . . .