Inclusion Criteria:  Participating in (ACTIV-3) TICO trial and received a selected blinded investigational agent, or placebo for that agent, at selected sites. Willingness to strictly adhere to the randomly allocated dosage number and schedule for vaccine administration. Participant is between Day 28 and Day 90 TICO visits inclusive at time of randomization. At time of screening for this study, has experienced sustained recovery for at least two consecutive weeks, i.e. having return uninterrupted to the person's premorbid living facility (or equivalent) for at least 2 consecutive weeks. Ability and willingness of participant (or legally authorized representative) to provide informed consent prior to initiation of any study procedures.  Exclusion Criteria:  Receipt of a SARS-CoV-2 (COVID-19) vaccine after enrollment into TICO. Participants who received a SARS-CoV-2 vaccine prior to enrollment in TICO may be enrolled in this study. Known allergy to any component of the study eligible vaccine(s).