Seropositivity for syphilis among Brazilian blood donors. A retrospective study 2015-2020.

INTRODUCTION: Syphilis is a transfusion-transmitted infection and the disease re-emerged in many countries, including Brazil, as a public health risk. OBJECTIVE: Evaluate the prevalence of positive serology in blood donations rejected by Hemobanco (Curitiba- PR) from January 2015 to December 2020, with special focus in syphilis. METHODOLOGY: In the studied period, we analyzed the number of blood donations discarded annually for each serological test performed on blood donors' samples, according to gender and donors age. RESULTS: Within the studied period, 134,741 blood donation were analyzed. 54.5 % of sample were male. Otherwise, it was observed a significant increase in the number of donations by females (P < 0.0001). There was an increase of 437 % in the prevalence of syphilis positive serology made by donors with ≥ 60 years. Besides that, it was noticed a significant increase in donations by aged people throughout these six years (P < 0.0001). The percentage of total blood donation deferred had a significant reduction, although it was observed an increase in the rate of discarded blood bags due to positive serology in the first 4 studied years. It was observed an increase of 20 % in positive syphilis serology. CONCLUSION: The greatest cause of discard of blood donations changed during the analyzed 5-years; there was an increase in seropositivity donations from donors with ≥ 60 years old. In 2015, Hepatitis B (0.8 %) was the most prevalent and in 2020, syphilis became more prevalent (0.82 %). The medical community should be aware of the rising number of cases of syphilis infection. There is an urgent need to implement actions against the dissemination of this disease.