Usability of SARS-CoV-2 Self-Testing in a Peer-Assisted Model among Factory Workers in Bengaluru, India: A Mixed- Methods Cross-Sectional Study

Background: To mitigate inequities in healthcare access and outcomes among vulnerable populations during the COVID-19 pandemic, the Government of India introduced antigen-based SARS-CoV-2 self-testing kits for self-use. However, concerns remained around the correct and confident use of these kits by low-literacy and underserved groups. This study aimed to assess the usability of nasal-sampling SARS-CoV-2 self-tests in a peer-assisted model among factory workers in Bengaluru, India. Methods: A mixed-method cross-sectional study was conducted with 106 factory workers across two industrial sites in Bengaluru between February and March 2022. The Panbio™ COVID-19 Antigen Self-Test kit and the NAVICA mobile app for result reporting were used. Peer assistants distributed kits, demonstrated procedures using their own kits (without physical contact), and guided participants in using the kit and app. Observers recorded usability, result interpretation, and peer instruction effectiveness using standardized checklists and contrived result images. Post-test surveys and focus group discussions captured user perceptions of facilitators and barriers to usability. Results: Study findings show that the overall usability score of the test kit with peer assistance was 75.9%, rising to 80.7% for critical steps and 33.8% for all critical steps in uploading results through NAVICA. It was seen that peer assistants provided accurate instructions and support for 93.4% of the tests. Among the critical steps in test kit use, maximum errors were made in sample collection and using the correct amount of buffer solution. Concordance between the participant and observer/NAVICA was 97.9%. 62.0% and 56.6% of the participants reported confidence in a) performing and interpreting the test and b) capturing and uploading their results using the mobile application with the assistance of a peer, respectively. Less than half the participants reported confidence in performing these steps independently. Conclusions: The study demonstrates that SARS-CoV-2 self-testing kits have good usability among factory workers when delivered through a peer-assisted model. Peer support significantly improved test accuracy and participant confidence. Such workplace-based, peer-led models can help improve equitable access to early detection and self-care tools in low-resource and high-risk populations.