This is a platform protocol designed to be flexible so that it is suitable for a range of interventions and settings within diverse health care systems and community settings with incorporation into clinical COVID-19 management programs and treatment plans if results achieve key study outcomes.

This protocol is a prospective, multi-center, multi-arm, randomized, controlled platform trial evaluating interventions to address and improve exercise intolerance and post-exertional malaise (PEM) as manifestations of Post-Acute Sequelae of SARS-CoV-2 Infection (PASC).

The focus of this protocol is to assess interventions that can improve exercise capacity, daily activities tolerance, and quality of life in patients with PASC.

Study interventions will be added to the platform protocol as appendices. Each appendix will leverage all elements of the platform protocol, with additional elements described in the individual appendix. Study intervention appendices may be added or removed according to adaptive design and/or emerging evidence.

The platform protocol enrolls participants who meet study eligibility criteria. After completing initial screening assessments, eligible participants are assigned to one of the study intervention appendices that are actively enrolling. Participants must meet certain criteria within a specific appendix in order to be included in that appendix. Once assigned to an appendix, eligible participants are randomized to either the study intervention group or a control group.

Inclusion Criteria:

1. ≥ 18 years of age at the time of enrollment

2. Previous suspected, probable, or confirmed SARS-CoV-2 infection, as defined by the Pan American Health Organization*

   • Suspected* or probable SARS-CoV-2 infection will only be allowed if it occurred before May 1, 2021, and will be limited to no more than 10% of the study population. Otherwise, confirmed cases are required.

   Suspected case of SARS-CoV-2 infection - Three options, A through C:

   A. A person who meets the clinical OR epidemiological criteria. Clinical criteria: Acute onset of fever AND cough (influenza-like illness) OR Acute onset of ANY THREE OR MORE of the following signs or symptoms: fever, cough, general, weakness/fatigue, headache, myalgia, sore throat, coryza, dyspnea, nausea, diarrhea, anorexia. Epidemiological criteria: Contact of a probable or confirmed case or linked to a COVID-19 cluster; or B. Acute respiratory infection with history of fever or measured fever of ≥ 38°C; and cough; with onset within the last 10 days; and who requires hospitalization; or C. With no clinical signs or symptoms, NOR meeting epidemiologic criteria with a positive professional use or self-test SARS-CoV-2 Antigen-Rapid Diagnostic Test.

   Probable case of SARS-CoV-2 infection:

   A. A patient who meets clinical criteria above AND is a contact of a probable or confirmed case or is linked to a COVID-19 cluster.

   Confirmed case of SARS-CoV-2 infection - Two options, A and B:

   A. A person with a positive nucleic acid amplification test, regardless of clinical criteria OR epidemiological criteria; or B. Meeting clinical criteria AND/OR epidemiological criteria (See suspected case A above for criteria). With a positive professional use or self-test SARS- CoV-2 Antigen-Rapid Diagnostic Test.

3. Self-reported limitation to physical activity due to the presence of symptoms such as fatigue, shortness of breath, and/or PEM following a SARS-CoV-2 infection, that has persisted for at least 12 weeks and is present at the time of consent.

4. Willing, able, and agree to provide informed consent, complete questionnaires and outcome assessments, and participate in the study, including assigned intervention or control and study visits whether remote, hybrid, or in-person.

Exclusion Criteria:

An individual who meets any of the following criteria will be excluded from participation in this study:

1. Known active acute SARS-CoV-2 infection ≤ 4 weeks prior to the consent.
2. Known prior diagnosis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), not related to SARS-CoV-2 infection.
3. Current or recent use (within the last 14 days) of a formal program utilizing one or more of the current study intervention(s) or similar intervention(s) to treat the underlying condition, unless a washout period is permitted per Appendices.
4. Participation in another interventional clinical trial.
5. Any condition that would make the participant, in the opinion of the investigator, unsuitable for the study.

The summary of the results will be shared on the study website: https://recovercovid.org/

Appendix A: Single (Outcomes Assessor masked) The assessor of the primary outcome, Endurance Shuttle Walk Test (ESWT), is blinded.

Appendix B: None (open label / no masking)