A5404

SARS-CoV-2 Immune Responses After COVID-19 Therapy and Subsequent Vaccine

This study is for people who had COVID-19 and participated in ACTIV-2/A5401 and received either experimental treatment, a standard of care COVID-19 treatment, or placebo. This study is also for people who have not previously had a COVID-19 infection. The study is designed to evaluate how the immune system responds to mRNA-COVID-19 vaccines in these participants. The safety of mRNA COVID-19 vaccines in persons with prior COVID-19 who did and did not receive prior experimental treatment for COVID-19 will be explored. Prior infection with or without treatment could increase, decrease, or have no significant effect on the response to mRNA COVID-19 vaccines, as well as the risk of side effects from these vaccines. Immune responses of participants who have not previously been infected with COVID-19 will be compared to those who have previously had COVID-19.