Use of chloroquine, hydroxychloroquine or ivermectin for Covid-19 prevention in vulnerable Brazilian populations.

OBJECTIVE: To explore factors associated with the use of chloroquine, hydroxychloroquine, and ivermectin for Covid-19 prevention in socioeconomically vulnerable populations in Brazil. METHODS: A cross-sectional study was conducted using data from the project "Expansion of testing, quarantine, digital health, and telemonitoring strategies to tackle the Covid-19 pandemic in Brazil. " Participants were users of 19 primary healthcare units in Salvador (Bahia, BA) and Rio de Janeiro (Rio de Janeiro, RJ) from July 2022 to July 2023. Data were collected via a socioeconomic questionnaire and analyzed using logistic regression to assess factors associated with the use of chloroquine, hydroxychloroquine, or ivermectin for Covid-19 prevention. Multicollinearity was assessed using the generalized variance inflation factor (GVIF), with GVIF^ (1/ (2*df) ) > 5 indicating potential collinearity. Sensitivity analyses were performed using the same backward selection procedure as the main model: excluding "sometimes" responses and stratifying analyses by city (Rio de Janeiro and Salvador). RESULTS: Among 7, 505 participants, 11. 7% reported using chloroquine, hydroxychloroquine, or ivermectin for Covid-19 prevention. Use was more frequent among people who identified themselves as Brown (ORa = 1. 38; 95%CI 1. 10-1. 75), aged 35-44 (ORa = 1. 34; 95%CI 1. 03-1. 75) or 44-59 (ORa = 1. 36; 95%CI 1. 06-1. 77), evangelical (ORa = 1. 32; 95%CI 1. 14-1. 53), and with comorbidities (ORa = 1. 25; 95%CI 1. 07-1. 47). Having up to two doses of Covid-19 vaccine (ORa = 1. 30; 95%CI 1. 06-1. 59) and being unvaccinated while living with someone with comorbidities (ORa = 10. 34; 95%CI 2. 27-53. 48) also increased the odds of use. GVIF values were low except for city (8. 79), due to its interaction with income; the variable was retained for conceptual reasons. Sensitivity analyses yielded results consistent with the main model. CONCLUSION: The use of ineffective medications for Covid-19 prevention was higher among specific demographic groups, reflecting inequalities in access to information and the influence of religious factors. Scientific communication and community engagement strategies remain essential to combat misinformation.