Design and Preliminary Findings of Adherence to the Self-Testing for Our Protection From COVID-19 (STOP COVID-19) Risk-Based Testing Protocol: Prospective Digital Study - Carly Herbert; Vik Kheterpal; Thejas Suvarna; John Broach; Juan Luis Marquez; Ben Gerber; Summer Schrader; Christopher Nowak; Emma Harman; William Heetderks; Nisha Fahey; Elizabeth Orvek; et al. (JMIR Formative Research, 2022)