Background: HIV self-tests (HIVST) have been freely distributed by the Brazilian public health system since December 2018. The Brazilian Ministry of Health (MoH) implemented HIVST reactive post-market surveillance by evaluation of feedbacks to subsidize future actions or improvements, as recommended by World Health Organization (WHO). Implementation process and results are described in this study. Methods: HIVST reactive post-market surveillance was implemented through MoH inclusion of an acquisition requirement for the manufacturer to provide a free, 24/7 Customer Service (CS). All CS calls are monthly reported by the manufacturer to the MoH and discussed through online meetings. Reports from December 2018 to December 2022 were analyzed including HIVST types of samples (total blood or oral fluid), calls descriptions, dates of opening and closure and CS conducts. Results: CS calls were first registered in February 2019 and 1,306 calls were received until December 2022. From all calls registered, 99.39% were user questions and only 0.61% were nonconformities reports, such as invalid results and missing items. Most of the user questions were related to results interpretation and reading time (53.56%), followed by HIVST window period (13.85%) and procedure (13.39%). Other categories represented less than 6% of the calls. Improvements in CS standard answers and in user guides information were made considering calls descriptions and conducts. CS calls regarding total blood HIVST represented 0.29% of the 394,422 distributed between December 2018 and March 2021. This percentage reduced to 0.04% between April 2021 and December 2022, when 470,593 oral fluid HIVST were distributed. Conclusions: Implementation of reactive post-market surveillance in Brazil showed a low percentage of calls related to HIVST distributed and that most doubts were related to results interpretation, which reinforces HIVST safety and good performance. Those features show a potential role of the HIVST reactive post-market surveillance in public policy creation and updates. Feedbacks subsidized improvements in acquisition criteria, which could be related to the reduction in the percentage of calls over time. However, other studies are necessary to evaluate this reduction and its relation with the types of samples and knowledge about self-testing among users.
