Phase 3 trial study design
RESOLUTION, SARS-COV-2 INFECTION
ENSEMBLE2 was a multinational, randomized, double-blind, placebo-controlled, phase 3 trial assessing the safety and efficacy of the Ad26.COV2.S vaccine for the prevention of COVID-19 in adults [In the ENSEMBLE2 trial, 31,300 participants were enrolled and randomized to receive Ad26.COV2.S (n = 15,708) or placebo (n = 15,592); a subset of participants was included in the present analysis. All participants in the ENSEMBLE2 trial were provided an electronic clinical outcome assessment tool, completed the SIC prior to first vaccine administration, and were monitored for the development of COVID-19 symptoms throughout the study. Participants reporting symptoms that suggested possible COVID-19 and those reporting any non-study positive-PCR tests were asked to complete 2 PRO measures daily throughout each suspected COVID-19 episode: the SIC was used to evaluate COVID-19 signs and symptoms, and the PGIS was used for validation. Additionally, participants reported blood oxygen saturation and pulse rate 3 times per day and body temperature daily during a COVID-19 episode. Nasal swabs were collected for detection of SARS-CoV-2 infection by reverse transcription (RT)–PCR within 1 to 2 days of symptom onset, on Days 3 to 5, and then every 2 days. Participants with ≥ 1 positive SARS-CoV-2 nasal swab returned to the study site 28 days (± 7 days) after symptom onset for clinical assessment and seroconfirmation of SARS-CoV-2 infection. Resolution of a COVID-19 episode was established by 2 consecutive, negative, SARS-CoV-2 nasal swabs and 2 consecutive days without COVID-19–related signs or symptoms.