Prevalence of Dengue, Chikungunya and Zika Viruses in Blood Donors in the State of Pará, Northern Brazil: 2018-2020.

Arboviruses have been reported over the years as constant threats to blood transfusion recipients, given the high occurrence of asymptomatic cases and the fact that the presence of viremia precedes the onset of symptoms, making it possible that infected blood from donors act as a source of dissemination. This work aims to identify the prevalence of dengue virus (DENV), Zika virus (ZIKV) and Chikungunya virus (CHIKV) infection in blood donors during epidemic and non-epidemic periods; classify the donor as symptomatic or asymptomatic; and verify the need to include DENV, CHIKV and ZIKV in the nucleic acid test (NAT) platform in northern Brazil. We investigated 36,133 thousand donations in two years of collection in Northern Brazil. One donor was positive for DENV and one for CHIKV (0.002% prevalence). As the prevalence for arboviruses was low in this study, it would not justify the individual screening of samples from donors in a blood bank. Thus, DENV- and CHIKV-positive samples were simulated in different amounts of sample pools, and both were safely detected by molecular biology even in a pool of 14 samples, which would meet the need to include these three viruses in the routine of blood centers in endemic countries such as Brazil.

Prevalence, incidence and residual risk of transfusion-transmitted HBV infection before and after the implementation of HBV-NAT in northern Brazil.

BACKGROUND: Nucleic 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. METHODS: The 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. RESULTS: HBV 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). CONCLUSIONS: The RR to HBV decreased after the implementation of HBV-NAT, increasing significantly the transfusional security in the North region of Brazil at HEMOPA Foundation.

Residual risk of transmission of human immunodeficiency virus and hepatitis C virus infections by blood transfusion in northern Brazil.

BACKGROUND: Nucleic acid test (NAT) blood screening for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) was introduced in northern Brazil in July 2012. There are several Brazilian articles that have evaluated transfusion transmission risks for HIV and HCV. However, to our knowledge, this article is the first to evaluate the impact of HIV and HCV NAT implementation for blood screening in northern Brazil. The aim of this study was to determine the prevalence and incidence rates of HIV and HCV among blood donors and to compare the residual risk of transfusion transmission of these infections, before (2009-2011) and after (2012-2014) NAT implementation. STUDY DESIGN AND METHODS: HIV and HCV prevalence and incidence were calculated based on rates of confirmed positive samples. Residual risk estimates were based on the incidence and window model described previously. Logistic and Poisson regressions were used in the statistical analysis. A p value of not more than 0.05 was considered significant. RESULTS: HIV and HCV prevalence were 209.9 and 66.3 per 100,000 donations, respectively. Residual risk for HIV and HCV decreased significantly throughout the two study periods, mainly for HCV in which the reduction was one in 169,492 to one in 769,231 donations. For HIV, the decrease was one in 107,527 to one in 769,231 donations. HIV and HCV incidence rates were 21.13 and 3.06 per 100,000 persons/year before NAT and 14.03 and 2.65 per 100,000 persons/year after NAT. CONCLUSION: The HIV and HCV NAT implementation significantly increased the transfusion safety in northern Brazil, bringing benefits to recipients due to better quality of blood products produced.