Surveillance for Zika, Chikungunya, and Dengue Virus Incidence and RNAemia in Blood Donors at 4 Brazilian Blood Centers During 2016-2019.

BACKGROUND: Except for public health case reports, the incidence of Zika virus (ZIKV), chikungunya virus (CHIKV), and dengue virus (DENV) infection are not available to assess the potential blood transfusion safety threat in Brazil. METHODS: Pools of 6 donation samples (MP6) left over from human immunodeficiency virus, hepatitis B virus, and hepatitis C virus nucleic acid testing were combined to create MP18 pools (3 MP6 pools). Samples were tested using the Grifols triplex ZIKV, CHIKV, and DENV real-time transcription mediated amplification assay to estimate prevalence of RNAemia and incidence, and to compare these results to case reports in São Paulo, Belo Horizonte, Recife, and Rio de Janeiro, from April 2016 through June 2019. RESULTS: ZIKV, CHIKV, and DENV RNAemia were found from donors who donated without overt symptoms of infection that would have led to deferral. The highest RNAemic donation prevalence was 1.2% (95% CI, .8%-1.9%) for DENV in Belo Horizonte in May 2019. Arbovirus infections varied by location and time of year, and were not always aligned with annual arbovirus outbreak seasons in different regions of the country. CONCLUSIONS: Testing donations for arboviruses in Brazil can contribute to public health. Transfusion recipients were likely exposed to ZIKV, CHIKV, and DENV viremic blood components during the study period.

Is Severity Score Associated With Indication for Hematopoietic Stem Cell Transplantation in Individuals With Sickle Cell Anemia?

Manifestations of sickle cell disease (SCD) begin early in childhood and cause morbidity and decreased life expectancy. Hematopoietic stem cell transplantation (HSCT) is curative but associated with risk of mortality attributable to the transplant. This risk should be counterbalanced with SCD morbidity and mortality. A severity score using a Bayesian network model was previously validated to predict the risk of death in adult individuals with SCD. The objective of this study is to calculate the severity scores of participants in a multicenter cohort of Brazilians with SCD, using a previously published Bayesian network-derived score, associated with risk of death and then compare the severity scores between participants with and without an indication for HSCT as defined by the Brazilian Ministry of Health (MoH) criteria. This is an observational, retrospective study. We analyzed 2063 individuals with sickle cell anemia from the Recipient Epidemiology and Donor Evaluation Study-III Brazil SCD cohort and applied a Bayesian network-derived score to compare candidates and non-candidates for HSCT according to the Brazilian MoH transplant criteria. Classical statistical methods were used to analyze data and make comparisons. We compared severity scores between cohort members with (n = 431) and without (n = 1632) HSCT indications according to Brazilian MoH. Scores were not different in adult participants with ≥1 HSCT indication when compared to those with no indication (mean 0.342 versus 0.292; median 0.194 versus 0.183, P = .354) and receiver operating characteristic curves did not demonstrate an obvious threshold to differentiate participants with or without HSCT indications. Severity score may predict risk of death but does not differentiate HSCT candidates. Current indications should be evaluated to ensure that patients with more severe disease who might benefit from HSCT are appropriately identified.

Clinical features and natural history of the first 2073 suspected COVID-19 cases in the Corona São Caetano primary care programme: a prospective cohort study.

BACKGROUND: Despite most cases not requiring hospital care, there are limited community-based clinical data on COVID-19. METHODS: The Corona São Caetano programme is a primary care initiative providing care to all residents with COVID-19 in São Caetano do Sul, Brazil. It was designed to capture standardised clinical data on community COVID-19 cases. After triage of potentially severe cases, consecutive patients presenting to a multimedia screening platform between 13 April and 13 May 2020 were tested at home with SARS-CoV-2 reverse transcriptase (RT) PCR; positive patients were followed up for 14 days with phone calls every 2 days. RT-PCR-negative patients were offered additional SARS-CoV-2 serology testing to establish their infection status. We describe the clinical, virological and natural history features of this prospective population-based cohort. FINDINGS: Of 2073 suspected COVID-19 cases, 1583 (76.4%) were tested by RT-PCR, of whom 444 (28.0%, 95% CI 25.9 to 30.3) were positive; 604/1136 (53%) RT-PCR-negative patients underwent serology, of whom 52 (8.6%) tested SARS-CoV-2 seropositive. The most common symptoms of confirmed COVID-19 were cough, fatigue, myalgia and headache; whereas self-reported fever (OR 3.0, 95% CI 2.4 to 3.9), anosmia (OR 3.3, 95% CI 2.6 to 4.4) and ageusia (OR 2.9, 95% CI 2.3 to 3.8) were most strongly associated with a positive COVID-19 diagnosis by RT-PCR or serology. RT-PCR cycle thresholds were lower in men, older patients, those with fever and arthralgia and closer to symptom onset. The rates of hospitalisation and death among 444 RT-PCR-positive cases were 6.7% and 0.7%, respectively, with older age and obesity more frequent in the hospitalised group. CONCLUSION: COVID-19 presents in a similar way to other mild community-acquired respiratory diseases, but the presence of fever, anosmia and ageusia can assist the specific diagnosis. Most patients recovered without requiring hospitalisation with a low fatality rate compared with other hospital-based studies.

Correction: Mortality among blood donors seropositive and seronegative for Chagas disease (1996-2000) in São Paulo, Brazil: A death certificate linkage study.

[This corrects the article DOI: 10.1371/journal.pntd.0005542.].

Test seeking: are healthcare professionals referring people to blood centers for infections marker testing?

ABSTRACT Background: Test-seeking is associated with HIV in Brazilian blood donors. This study sought to investigate the frequency with which three different donor groups: deferred donors, accepted donors who tested HIV positive [HIV (+)], and accepted donors who tested infectious disease markers negative [IDM (−)], came to the blood bank at the suggestion of a health care professional. Study design and methods: Donors deferred for reporting high-risk behaviors and participants in an HIV risk factor case-control study completed a confidential audio computer-assisted self-interview (ACASI) that included two questions related to health care professionals and test-seeking. Results: Of 4013 enrolled deferred donors, 468 (11.8%) reported a health care professional suggested donation as a way to be tested for infection. Of 341 HIV (+) and 791 IDM (−) participants, 43 (12.6%) and 11 (1.4%), respectively, reported a health care professional suggested donation as a way to be tested for infection. Physicians were the most frequently reported source of referral: [(61.5% of deferred, 69.1% of HIV (+), and 9.1% of IDM (−) donors)]. Conclusion: HIV (+) donors and deferred donors were 10 times more likely to report test-seeking behavior by suggestion of health care professional than IDM (−) donors. If true, efforts should be made to educate health care professionals and blood donors on how to safeguard the blood supply, emphasizing that HIV testing should be done at volunteer testing centers rather than at the blood centers.

Test seeking: are healthcare professionals referring people to blood centers for infections marker testing?

BACKGROUND: Test-seeking is associated with HIV in Brazilian blood donors. This study sought to investigate the frequency with which three different donor groups: deferred donors, accepted donors who tested HIV positive [HIV (+)], and accepted donors who tested infectious disease markers negative [IDM (-)], came to the blood bank at the suggestion of a health care professional. STUDY DESIGN AND METHODS: Donors deferred for reporting high-risk behaviors and participants in an HIV risk factor case-control study completed a confidential audio computer-assisted self-interview (ACASI) that included two questions related to health care professionals and test-seeking. RESULTS: Of 4013 enrolled deferred donors, 468 (11.8%) reported a health care professional suggested donation as a way to be tested for infection. Of 341 HIV (+) and 791 IDM (-) participants, 43 (12.6%) and 11 (1.4%), respectively, reported a health care professional suggested donation as a way to be tested for infection. Physicians were the most frequently reported source of referral: [(61.5% of deferred, 69.1% of HIV (+), and 9.1% of IDM (-) donors)]. CONCLUSION: HIV (+) donors and deferred donors were 10 times more likely to report test-seeking behavior by suggestion of health care professional than IDM (-) donors. If true, efforts should be made to educate health care professionals and blood donors on how to safeguard the blood supply, emphasizing that HIV testing should be done at volunteer testing centers rather than at the blood centers.

Clinical and genetic ancestry profile of a large multi-centre sickle cell disease cohort in Brazil.

Approximately 3500 children with sickle cell disease (SCD) are born in Brazil each year, but the burden of SCD morbidity is not fully characterised. A large, multi-centre cohort was established to characterise clinical outcomes in the Brazilian SCD population and create the infrastructure to perform genotype-phenotype association studies. Eligible patients were randomly selected from participating sites and recruited at routine visits. A biorepository of blood samples was created and comprehensive demographic and clinical outcome data were entered in a centralized electronic database. Peripheral blood genome-wide single nucleotide polymorphism (SNP) genotyping was performed using a customized Transfusion Medicine (TM) Array. A total of 2795 participants at six Brazilian sites were enrolled between 2013 and 2015. The cohort included slight predominance of children <18 years (55·9%) and females (53·0%). Haemoglobin (Hb) SS was the most common SCD genotype (70·7%), followed by HbSC (23%), Sß0 (3·0%) and Sß+ (2·9%). SNP data from the TM Array were analysed to evaluate the genetic ancestry of the cohort and revealed significant admixture among the population. Demographics and clinical complications, stratified by age and SCD genotype, are summarized and future studies in this cohort are discussed.

Mortality among blood donors seropositive and seronegative for Chagas disease (1996-2000) in São Paulo, Brazil: A death certificate linkage study.

BACKGROUND: Individuals in the indeterminate phase of Chagas disease are considered to have mortality rates similar to those of the overall population. This study compares mortality rates among blood donors seropositive for Chagas disease and negative controls in the city of São Paulo, Brazil. METHODOLOGY/PRINCIPAL FINDINGS: This is a retrospective cohort study of blood donors from 1996 to 2000: 2842 seropositive and 5684 seronegative for Chagas disease. Death status was ascertained by performing probabilistic record linkage (RL) with the Brazil national mortality information system (SIM). RL was assessed in a previous validation study. Cox Regression was used to derive hazard ratios (HR), adjusting for confounders. RL identified 159 deaths among the 2842 seropositive blood donors (5.6%) and 103 deaths among the 5684 seronegative (1.8%). Out of the 159 deaths among seropositive donors, 26 had the 10th International Statistical Classification of Diseases and Related Health Problems (ICD-10) indicating Chagas disease as the underlying cause of death (B57.0/B57.5), 23 had ICD-10 codes (I42.0/I42.2/I47.0/I47.2/I49.0/I50.0/I50.1/ I50.9/I51.7) indicating cardiac abnormalities possibly related to Chagas disease listed as an underlying or associated cause of death, with the others having no mention of Chagas disease in part I of the death certificate. Donors seropositive for Chagas disease had a 2.3 times higher risk of death due to all causes (95% Confidence Interval (95% CI), 1.8-3.0) than seronegative donors. When considering deaths due to Chagas disease or those that had underlying causes of cardiac abnormalities related to Chagas disease, seropositive donors had a risk of death 17.9 (95% CI, 6.3-50.8) times greater than seronegative donors. CONCLUSIONS/SIGNIFICANCE: There is an excess risk of death in donors seropositive blood for Chagas disease compared to seronegative donors. Chagas disease is an under-reported cause of death in the Brazilian mortality database.

Hepatitis C among blood donors: cascade of care and predictors of loss to follow-up.

OBJECTIVE: To investigate the HCV cascade of care and to identify the factors associated with loss or absence to follow-up of patients identified as infected with hepatitis C through blood donation. METHODS: Blood donors from 1994 to 2012, identified with positive anti- HCV by enzyme immunoassay and immunoblot tests were invited to participate in the study, through letters or phone calls. Patients who agreed to participate were interviewed and their blood samples were collected for further testing. The following variables were investigated: demographic data, data on comorbidities and history concerning monitoring of hepatitis C. Multiple regression analysis by Poisson regression model was used to investigate the factors associated with non-referral for consultation or loss of follow-up. RESULTS: Of the 2,952 HCV-infected blood donors, 22.8% agreed to participate: 394 (58.2%) male, median age 48 years old and 364 (53.8%) Caucasian. Of the 676 participants, 39.7% did not receive proper follow-up or treatment after diagnosis: 45 patients referred not to be aware they were infected, 61 did not seek medical attention and 163 started a follow-up program, but were non-adherent. The main reasons for inadequate follow-up were not understanding the need for medical care (71%) and health care access difficulties (14%). The variables showing a significant association with inadequate follow-up after multiple regression analysis were male gender (PR = 1.40; 95%CI 1.15-1.71), age under or equal to 50 years (PR = 1.36; 95%CI 1.12-1.65) and non-Caucasians (PR = 1.53; 95%CI 1.27-1.84). CONCLUSIONS: About 40.0% of patients did not receive appropriate follow-up. These data reinforce the need to establish strong links between primary care and reference centers and the need to improve access to specialists and treatments.

Hepatitis C among blood donors: cascade of care and predictors of loss to follow-up

ABSTRACT OBJECTIVE To investigate the HCV cascade of care and to identify the factors associated with loss or absence to follow-up of patients identified as infected with hepatitis C through blood donation. METHODS Blood donors from 1994 to 2012, identified with positive anti- HCV by enzyme immunoassay and immunoblot tests were invited to participate in the study, through letters or phone calls. Patients who agreed to participate were interviewed and their blood samples were collected for further testing. The following variables were investigated: demographic data, data on comorbidities and history concerning monitoring of hepatitis C. Multiple regression analysis by Poisson regression model was used to investigate the factors associated with non-referral for consultation or loss of follow-up. RESULTS Of the 2,952 HCV-infected blood donors, 22.8% agreed to participate: 394 (58.2%) male, median age 48 years old and 364 (53.8%) Caucasian. Of the 676 participants, 39.7% did not receive proper follow-up or treatment after diagnosis: 45 patients referred not to be aware they were infected, 61 did not seek medical attention and 163 started a follow-up program, but were non-adherent. The main reasons for inadequate follow-up were not understanding the need for medical care (71%) and health care access difficulties (14%). The variables showing a significant association with inadequate follow-up after multiple regression analysis were male gender (PR = 1.40; 95%CI 1.15–1.71), age under or equal to 50 years (PR = 1.36; 95%CI 1.12–1.65) and non-Caucasians (PR = 1.53; 95%CI 1.27–1.84). CONCLUSIONS About 40.0% of patients did not receive appropriate follow-up. These data reinforce the need to establish strong links between primary care and reference centers and the need to improve access to specialists and treatments.

Duration of Dengue Viremia in Blood Donors and Relationships Between Donor Viremia, Infection Incidence and Clinical Case Reports During a Large Epidemic.

BACKGROUND: Dengue viruses (DENV-1-4) pose a transfusion-transmission risk. This study estimated the dengue RNA detection period in asymptomatic blood donors and relationships between donor viremia and dengue incidence during a large epidemic. METHODS: Donor samples from the 2012 dengue transmission season in Rio de Janeiro, Brazil, were tested for DENV RNA by a transcription-mediated amplification (TMA) assay, with DENV types and viral loads determined by polymerase chain reaction. Samples collected during the first and last weeks of enrollment were tested for DENV immunoglobulin (Ig) G and IgM to estimate incidence during the study period, which was analyzed relative to nucleic acid amplification technology (NAT) yield to estimate the duration of NAT-detectable viremia and compared with reported clinical dengue cases in Rio. RESULTS: Samples from 16 241 donations were tested; 87 (0.54%) were confirmed as DENV-4 RNA positive. Dengue IgM-positive/IgG-positive reactivity increased from 2.8% to 8.8%, indicating a 6.2% incidence (95% confidence interval [CI], 3.2%-9.1%) during the study period. Based on these data, we estimated a 9.1-day period (95% CI, 4.4-13.9 days) of RNA detectable with TMA. With 100 475 reported cases of clinical dengue, 1 RNA-positive donation was identified per 800 DENV cases. CONCLUSIONS: These parameters allow projections of dengue incidence from donor NAT yield data and vice versa, and suggest that viremic donations will be rare relative to clinical disease cases.

Transfusion-Transmitted Dengue and Associated Clinical Symptoms During the 2012 Epidemic in Brazil.

BACKGROUND: A linked donor-recipient study was conducted during epidemics in 2 cities in Brazil to investigate transfusion-transmitted (TT) dengue virus (DENV) by DENV RNA-positive donations. METHODS: During February-June 2012, samples were collected from donors and recipients and retrospectively tested for DENV RNA by transcription-mediated amplification. Recipient chart review, using a case (DENV positive)-control (DENV negative and not known to be exposed) design, was conducted to assess symptoms. RESULTS: Of 39 134 recruited blood donors, DENV-4 viremia was confirmed in 0.51% of donations from subjects in Rio de Janeiro and 0.80% of subjects in Recife. Overall, 42 DENV RNA-positive units were transfused into 35 recipients. Of these, 16 RNA-positive units transfused into 16 susceptible recipients were identified as informative: 5 cases were considered probable TT cases, 1 possible TT case, and 10 nontransmissions. The TT rate was 37.5% (95% confidence interval [CI], 15.2%-64.6%), significantly higher than the viremia rate of 0.93% (95% CI, .11%-3.34%) in nonexposed recipients (P < .0001). Chart review did not find significant differences between cases and controls in symptoms or mortality. CONCLUSIONS: During a large epidemic of DENV-4 infection in Brazil, >0.5% of donations were RNA positive, and approximately one third of components resulted in TT. However, no significant clinical differences were evident between RNA-positive and RNA-negative recipients.

Accuracy of a probabilistic record-linkage methodology used to track blood donors in the Mortality Information System database.

The probabilistic record linkage (PRL) is based on a likelihood score that measures the degree of similarity of several matching variables. Screening test results for different diseases are available for the blood donor population. In this paper, we describe the accuracy of a PRL process used to track blood donors from the Fundação Pró-Sangue (FPS) in the Mortality Information System (SIM), in order that future studies might determine the blood donor's cause of death. The databases used for linkage were SIM and the database made up of individuals that were living (200 blood donors in 2007) and dead (196 from the Hospital das Clinicas de São Paulo that died in 2001-2005). The method consists of cleaning and linking the databases using three blocking steps comparing the variables "Name/Mother's Name/ Date of Birth" to determine a cut-off score. For a cut-off score of 7.06, the sensitivity and specificity of the method is 94.4% (95%CI: 90.0-97.0) and 100% (95%CI: 98.0-100.0), respectively. This method can be used in studies that aim to track blood donors from the FPS database in SIM.

Accuracy of a probabilistic record-linkage methodology used to track blood donors in the Mortality Information System database / Acurácia da metodologia de relacionamento probabilístico de registros na identificação de doadores de sangue no banco de dados do Sistema de Informações sobre Mortalidade / La exactitud del método probabilístico de relación para identificar a donantes de sangre en la base de datos del Sistema de Información sobre Mortalidad

The probabilistic record linkage (PRL) is based on a likelihood score that measures the degree of similarity of several matching variables. Screening test results for different diseases are available for the blood donor population. In this paper, we describe the accuracy of a PRL process used to track blood donors from the Fundação Pró-Sangue (FPS) in the Mortality Information System (SIM), in order that future studies might determine the blood donor’s cause of death. The databases used for linkage were SIM and the database made up of individuals that were living (200 blood donors in 2007) and dead (196 from the Hospital das Clinicas de São Paulo that died in 2001-2005). The method consists of cleaning and linking the databases using three blocking steps comparing the variables “Name/Mother’s Name/ Date of Birth” to determine a cut-off score. For a cut-off score of 7.06, the sensitivity and specificity of the method is 94.4% (95%CI: 90.0-97.0) and 100% (95%CI: 98.0-100.0), respectively. This method can be used in studies that aim to track blood donors from the FPS database in SIM.

O relacionamento probabilístico se baseia em um escore que é calculado levando em consideração a similaridade do pareamento de diversas variáveis. Dados de resultados de testes de triagem para diferentes doenças estão disponíveis para a população de doadores de sangue. Neste artigo descrevemos a acurácia de um processo de relacionamento probabilístico para identificar doadores de sangue da Fundação Pró-Sangue (FPS) no Sistema de Informações sobre Mortalidade (SIM). Os bancos utilizados para o relacionamento foram o SIM e o banco formado por indivíduos vivos (200 doadores de sangue em 2007) e mortos (196 pacientes do Hospital das Clínicas de São Paulo que morreram entre 2001-2005). O método consistiu em limpar e relacionar probabilísticamente os bancos em três passos de blocagem comparando as variáveis “Nome/Nome Mãe /Data de Nascimento” para determinar um escore de corte. Para um escore de corte de 7,06 a sensibilidade e especificidade do método é de 94,4% (IC95%: 90-97) e 100% (IC95%: 98-100), respectivamente. Este método pode ser utilizado em estudos para identificar pacientes da FPS no SIM.

La relación probabilística (RP) se basa en una puntuación que se calcula en función de la similitud entre variables de emparejamiento. Los resultados de los tests sobre diferentes enfermedades están a disposición de la población de donantes de sangre. En el presente artículo se describe la precisión de un proceso de RP para identificar a donantes de sangre de la Fundação Pró-Sangue (FPS) en el Sistema de Información de Mortalidad (SIM). Se llevó a cabo la RP del SIM y de un banco compuesto por individuos vivos (200 donantes de sangre en 2007) y muertos (196 pacientes del Hospital de Clínicas de São Paulo, que murieron entre 2001 y 2005). El método consistió en depurar los bancos de datos y RP en tres etapas de bloqueo, comparando las variables nombre, nombre de la madre y fecha de nacimiento para determinar un punto de corte. Para el punto de corte 7:06, la especificidad y sensibilidad del método fue de un 94,4% (IC95%: 90,0-97,0) y 100% (IC95%: 98,0-100,0), respectivamente. Este método puede ser utilizado en más estudios con el fin de identificar a los pacientes FPS en el SIM.

Contribution of the Retrovirus Epidemiology Donor Study (REDS) to research on blood transfusion safety in Brazil.

The Retrovirus Epidemiology Donor Study (REDS) program was established in the United States in 1989 with the purpose of increasing blood transfusion safety in the context of the HIV/AIDS and human T-lymphotropic virus epidemics. REDS and its successor, REDS-II were at first conducted in the US, then expanded in 2006 to include international partnerships with Brazil and China. In 2011, a third wave of REDS renamed the Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) was launched. This seven-year research program focuses on both blood banking and transfusion medicine research in the United States of America, Brazil, China, and South Africa. The main goal of the international programs is to reduce and prevent the transmission of HIV/AIDS and other known and emerging infectious agents through transfusion, and to address research questions aimed at understanding global issues related to the availability of safe blood. This article describes the contribution of REDS-II to transfusion safety in Brazil. Articles published from 2010 to 2013 are summarized, including database analyses to characterize blood donors, deferral rates, and prevalence, incidence and residual risk of the main blood-borne infections. Specific studies were developed to understand donor motivation, the impact of the deferral questions, risk factors and molecular surveillance among HIV-positive donors, and the natural history of Chagas disease. The purpose of this review is to disseminate the acquired knowledge and briefly summarize the findings of the REDS-II studies conducted in Brazil as well as to introduce the scope of the REDS-III program that is now in progress and will continue through 2018.

Contribution of the Retrovirus Epidemiology Donor Study (REDS) to research on blood transfusion safety in Brazil

The Retrovirus Epidemiology Donor Study (REDS) program was established in the United States in 1989 with the purpose of increasing blood transfusion safety in the context of the HIV/AIDS and human T-lymphotropic virus epidemics. REDS and its successor, REDS-II were at first conducted in the US, then expanded in 2006 to include international partnerships with Brazil and China. In 2011, a third wave of REDS renamed the Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) was launched. This seven-year research program focuses on both blood banking and transfusion medicine research in the United States of America, Brazil, China, and South Africa. The main goal of the international programs is to reduce and prevent the transmission of HIV/AIDS and other known and emerging infectious agents through transfusion, and to address research questions aimed at understanding global issues related to the availability of safe blood. This article describes the contribution of REDS-II to transfusion safety in Brazil. Articles published from 2010 to 2013 are summarized, including database analyses to characterize blood donors, deferral rates, and prevalence, incidence and residual risk of the main blood-borne infections. Specific studies were developed to understand donor motivation, the impact of the deferral questions, risk factors and molecular surveillance among HIV-positive donors, and the natural history of Chagas disease. The purpose of this review is to disseminate the acquired knowledge and briefly summarize the findings of the REDS-II studies conducted in Brazil as well as to introduce the scope of the REDS-III program that is now in progress and will continue through 2018.

Temporal distribution of blood donations in three Brazilian blood centers and its repercussion on the blood supply.

BACKGROUND: Seasonal distribution of blood donation hinders efforts to provide a safe and adequate blood supply leading to chronic and persistent shortages. This study examined whether holidays, geographical area and donation type (community versus replacement) has any impact on the fluctuation of donations. METHODS: The numbers of blood donations from 2007 through 2010 in three Brazilian Retrovirus Epidemiological Donor Study II (REDS-II) participating centers were analyzed according to the week of donation. The weeks were classified as holiday or non-holiday. To compare donations performed during holiday versus non-holiday weeks, tabulations and descriptive statistics for weekly donations by blood center were examined and time series analysis was conducted. RESULTS: The average weekly number of donations varied according to the blood center and type of week. The average number of donations decreased significantly during Carnival and Christmas and increased during the Brazilian National Donor Week. The fluctuation was more pronounced in Recife and Belo Horizonte when compared to São Paulo and higher among community donors. CONCLUSION: National bank holidays affect the blood supply by reducing available blood donations. Blood banks should take into account these oscillations in order to plan local campaigns, aiming at maintaining the blood supply at acceptable levels.