BackgroundNucleic acid testing (NAT) for virus detection during blood screening has helped to prevent transfusion-transmitted infections worldwide. In northern Brazil, NAT was implemented in 2012 for HIV and HCV and more recently, in January 2015, the screening for HBV was included and currently used concomitant with serological tests (HBsAg and anti-HBc). This study aims to evaluate the prevalence and the incidence of HBV infection among voluntary blood donors at ten regional blood centers of HEMOPA Foundation in Pará state and to compare the residual risk of transfusion-transmitted HBV infection before and after the Brazilian HBV-NAT implementation.MethodsThe prevalence (restricted to first time donors- FT) and seroconversion rate (restricted to repeat donors- RP) of HBV were calculated based on rates of confirmed positive samples. Residual risk was based on the incidence and window period (WP) model described by Schreiber and coauthors. Logistic and Poisson regression were used in the statistical analysis by SPSS v20.0. A p value <0.05 was considered statistically significant.ResultsHBV prevalence in the periods before and after the implementation of HBV-NAT were 247 and 251 per 100,000 donations, respectively. Seroconversion rates were 114 and 122 per 100,000 donations in the two periods, respectively. The residual risk (RR) for HBV decreased significantly in the posterior period to the HBV-NAT implementation, when compared to RR before implementation, with a reduction of 1:144,92 to 1:294,11 donations (p <0,001).ConclusionsThe RR to HBV decreased after the implementation of HBV-NAT, increasing significantly the transfusional security in the North region of Brazil at HEMOPA Foundation.

Background: The Human T Cell Lymphotropic Virus (HTLV) is a retrovirus of the genus Deltaretrovirus, which belongs to the family Retroviridae, and has tropism for T lymphocytes. This virus has four types, of which the most important in terms of pathogenesis and epidemiology are HTLV-1 and HTLV -2. It is estimated that between five and 10 million individuals are infected with HTLV-1, worldwide, of which, approximately 2.5 million live in Brazil. Studies in the state of Pará indicate that it has the third highest prevalence of HTLV infections of any Brazilian state. The virus can betransmitted through sexual, vertical, and parenteral route. The present study describes the epidemiological, serological, and molecular profile of blood donors from the state of Pará, that were classified as unfit due to infection by HTLV-1 and 2. Results: A total of 632 samples were analyzed. The HTLV proviral DNA was detected primarily in females (69.1%), with a mean age of 40 years, with the highest frequencies of detection being recorded in single individuals (66.2%), first-time donors (74.3%), and individuals that had graduated high school (44.1%). The molecular confirmation of HTLV showed that threequarters (78%) of the serologically reactive individuals were negative for either types I or II, so the epidemiological profile of these individuals was significantly different from their detectable profile. Conclusions: The HTLV is a neglected etiological agent in Brazil, and although there have been many advances since its discovery, infection patterns are still relatively poorly understood by both healthcare professionals and the general population. There is thus a clear need for further research in the area of regional hemotherapy and hematology services, in order to contribute to the definition of regional infection profiles, that will be fundamental to the development of effective prophylactic practises for the prevention of the infection and the dissemination of knowledge on the dangers of HTLV in the community.

No abstract

The present study aims to correlate the sample-to-cutoff ratios (S/CO) distributions of reactive results for HTLV-1/2 antibodies with the detection of proviral DNA in a population of blood donor candidates. It was carried out a retrospective data search of 632 HTLV-1/2 reactive samples, submitted to confirmatory testing from January 2015 to December 2019. Serological screening was performed by chemiluminescent microparticle immunoassay Architect rHTLV-I/II, whereas confirmatory testing was performed by in-house real-time polymerase chain reaction method. 496 out of 632 samples (78%) had undetectable HTLV-1/2 proviral DNA and 136 (22%) had detectable proviral DNA. HTLV infection was not confirmed in any individual for whom the S/CO ratio value was <4, and proviral DNA detection rates gradually escalated as S/CO ratio values increased. The sensitivity and predictive positive value found for the Architect rHTLV-I/II was 100% and 22%, respectively. The receiver operating characteristic (ROC) curve analysis showed that the optimal S/CO ratio value for predicting the presence of HTLV-1/2 was 18.11. High S/CO ratios were more associated with the detection of proviral DNA. The S/CO ratio value <4 suggests excluding true HTLV infection and the risk of blood transmission.

No abstract