For this appendix of the master protocol (NCT05595369), participants will be randomized to Paxlovid (nirmatrelvir/ritonavir) vs. ritonavir control plus nirmatrelvir-matching placebo.
When there are multiple study interventions (sub-studies) available under the master protocol (NCT05595369), randomization will occur based on the specific inclusion/exclusion criteria of each appendix.