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

ABSTRACT 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.