Trial Outcomes & Findings for Longitudinal COVID-19 Antibody Testing in Indiana University Undergraduate Students (NCT NCT04620798)

We randomly sampled 7,499 students from the sampling frame of all IU Bloomington undergraduates enrolled at the beginning of the Fall 2020 semester. Students in the sample were eligible to participate if they were (1) aged 18 years or older, (2) a current IU Bloomington undergraduate student, and (3) currently residing in Monroe County, Indiana. Of those sampled, 4,069 potential participants met the inclusion criteria for the study and were contacted by email with a study invitation.

Following the study invitation, 1076 of the 4069 eligible sampled students were enrolled in the study and received randomization. 2651 students tacitly refused participation, 21 students explicitly refused participation or withdrew from the study, and 321 students missed the baseline study visit.

Only includes participants who self-reported their age at baseline (66 participants were missing this data).

This outcome was dichotomized into Always and Very Often versus Sometimes, Rarely, and Never. It will be self-reported in a web-based follow-up survey administered at 2 weeks after the baseline antibody test, with an item adapted from the WHO 2020 "Monitoring knowledge, risk perceptions, preventive behaviours and trust to inform pandemic outbreak response": "During the last 7 days, which of the following measures have you taken to prevent infection from COVID-19?" -Frequently washed my hands with soap and water for at least 20 seconds Response options are: Always, Very Often, Sometimes, Rarely, Never

This outcome was dichotomized into Always and Very Often versus Sometimes, Rarely, and Never. This outcome will be self-reported in a web-based follow-up survey administered at 2 weeks after the baseline antibody test, with an item adapted from the WHO 2020 "Monitoring knowledge, risk perceptions, preventive behaviours and trust to inform pandemic outbreak response": "During the last 7 days, which of the following measures have you taken to prevent infection from COVID-19?" -Avoided touching my eyes, nose and mouth with unwashed hands Response options are: Always, Very Often, Sometimes, Rarely, Never

This outcome was dichotomized into Always and Very Often versus Sometimes, Rarely, and Never. This outcome will be self-reported in a web-based follow-up survey administered at 2 weeks after the baseline antibody test, with an item adapted from the WHO 2020 "Monitoring knowledge, risk perceptions, preventive behaviours and trust to inform pandemic outbreak response": "During the last 7 days, which of the following measures have you taken to prevent infection from COVID-19?" -Used disinfectants or hand sanitizer to clean hands when soap and water were not available Response options are: Always, Very Often, Sometimes, Rarely, Never

This outcome was dichotomized into Always and Very Often versus Sometimes, Rarely, and Never. It will be self-reported in a web-based follow-up survey administered at 2 weeks after the baseline antibody test, with an item adapted from the WHO 2020 "Monitoring knowledge, risk perceptions, preventive behaviours and trust to inform pandemic outbreak response": "During the last 7 days, which of the following measures have you taken to prevent infection from COVID-19?" -Avoided a social event I wanted to attend Response options are: Always, Very Often, Sometimes, Rarely, Never

This outcome is dichotomized into Always and Very Often versus Sometimes, Rarely, and Never. It will be self-reported in a web-based follow-up survey administered at 2 weeks after the baseline antibody test, with an item adapted from the WHO 2020 "Monitoring knowledge, risk perceptions, preventive behaviours and trust to inform pandemic outbreak response": "During the last 7 days, which of the following measures have you taken to prevent infection from COVID-19?" -Stayed at home from work/school Response options are: Always, Very Often, Sometimes, Rarely, Never

This outcome is dichotomized into Always versus Very Often, Sometimes, Rarely, and Never. It will be self-reported in a web-based follow-up survey administered at 2 weeks after the baseline antibody test, with an item adapted from the WHO 2020 "Monitoring knowledge, risk perceptions, preventive behaviours and trust to inform pandemic outbreak response": "During the last 7 days, which of the following measures have you taken to prevent infection from COVID-19?" -Wore a mask in public Response options are: Always, Very Often, Sometimes, Rarely, Never

This outcome is dichotomized into Always and Very Often versus Sometimes, Rarely, and Never. It will be self-reported in a web-based follow-up survey administered at 2 weeks after the baseline antibody test, with an item adapted from the WHO 2020 "Monitoring knowledge, risk perceptions, preventive behaviours and trust to inform pandemic outbreak response": "During the last 7 days, which of the following measures have you taken to prevent infection from COVID-19?" -Ensured physical distancing in public Response options are: Always, Very Often, Sometimes, Rarely, Never

This outcome was dichotomized into Always and Very Often versus Sometimes, Rarely, and Never. This outcome will be self-reported in a web-based follow-up survey administered at 2 weeks after the baseline antibody test, with an item adapted from the WHO 2020 "Monitoring knowledge, risk perceptions, preventive behaviours and trust to inform pandemic outbreak response": "During the last 7 days, which of the following measures have you taken to prevent infection from COVID-19?" -Avoided contact with people at high-risk for severe COVID-19 infections Response options are: Always, Very Often, Sometimes, Rarely, Never

This outcome will be assessed by comparing SARS-CoV-2 serostatus at baseline (September 2020) and endline (November 2020). Those who were antibody negative at baseline but antibody positive at endline will be considered seroconverters in this study.