COVID-19 Testing and Preventive Behaviours During The Pandemic’s Onset: A Cross-sectional Study

Objective: This study aimed to analyze individual exposure to SARS-CoV-2 and engagement in preventive practices at the onset of the COVID-19 pandemic. Method: A population-based cross-sectional survey (Test to Care) was conducted in São Carlos, SP, Brazil, using stratified random sampling by census sectors. One adult per household was interviewed and tested for anti-SARS-CoV-2-S1 IgG antibodies. Data included demographics, comorbidities, recent symptoms, and adherence to hygiene and social distancing measures. Results: Among 3,921 participants, 91.6% reported reduced mobility. Lower adherence was associated with younger age, male sex, marital union, inhaled drug use, school-aged children at home, and lack of social benefits. Mask use was high (97.1%) but less frequent among men. One-third had flu-like symptoms; 1.1% were hospitalized. Seroprevalence was 1.74%, associated with male sex, absence of alcohol use, and previous symptoms. Case clusters were concentrated in low-income areas. Conclusion: Understanding barriers to preventive behavior is essential for guiding public health strategies and reducing vulnerabilities to respiratory infections.