Observational Cohort Studies

RECOVER researchers study large groups of people (called cohorts) over several years. Studying these cohorts helps researchers better understand:

• Who gets Long COVID.
• Why people get Long COVID.
• What Long COVID symptoms people have.
• How Long COVID affects people’s health over time.

Participants, researchers, and study sites across the United States, Puerto Rico, and Canada contribute to RECOVER observational cohort studies. 

Enrollment in RECOVER’s observational cohort studies is now complete.

People who joined these studies belong to one of two main cohorts:

• Children and young adults aged 25 or younger, along with their caregivers.

• Adults aged 18 or older, including pregnant women.

  • Women who were pregnant during or after 2020 joined the adult study. Their children joined the pediatric (children and young adult) study as the group exposed to SARS-CoV-2, the virus that causes COVID-19, in utero (before birth).

Each cohort also includes a control group, which is a group of people who have not had COVID-19. Including this control group allows researchers to compare the long-term health of people who’ve had and haven’t had COVID-19.

By including people from all walks of life, RECOVER observational cohort studies help us understand how Long COVID can affect everyone differently.

People participating in RECOVER observational cohort studies share information about their health with researchers. Participants do not receive Long COVID treatments or change their regular healthcare.

Participants share their health information with researchers by regularly completing surveys. Participants may also complete in-person study visits at a hospital or doctor’s office once or twice a year for as long as the study continues.

During these visits, participants may:

• Answer questions about their life and health.
• Get a checkup.
• Provide small amounts of tissue, blood, urine (pee), or saliva, called biospecimens (biosamples).
• Get an X-ray or CT scan, so researchers can see what is happening inside their bodies.
• Take other health tests, such as strength tests and cognitive tests (tests that measure a person’s ability to think, reason, and understand).

Between surveys and visits, researchers may ask observational cohort study participants to keep track of their symptoms, physical activity, and sleep patterns. Researchers may also ask some participants to mail biosamples to a study site. Additionally, researchers may contact the participant’s doctor about their test results or provide test results directly to participants so they can discuss those results with their doctor.

RECOVER observational cohort studies focus on learning how Long COVID affects people’s health over time. This includes people of all ages, sexes, backgrounds, and walks of life. Some people will continue to take part in RECOVER observational cohort studies in a second phase that extends the length of their initial participation.

The first phase of the RECOVER adult observational cohort study ended on October 31, 2025. Participants have completed all activities in the first phase of the study. The pediatric cohort and tissue pathology (autopsy) studies are ongoing. 

Research conducted during the first phase of the RECOVER adult observational cohort study produced important findings about:

• Why some people get Long COVID and others don’t.
• The broad range of symptoms experienced by people with Long COVID.
• How long it can take for Long COVID symptoms to improve.
• Whether having COVID-19 during pregnancy can cause long-term health problems or change a woman’s chance of getting Long COVID.

The next phase of the RECOVER adult observational cohort study began on May 4, 2026, and will continue for another 2 years. During this phase, a smaller group of people already enrolled in the study will continue to answer survey questions, complete health check-ins, take a variety of health tests, and donate blood samples. The data collected during this phase of the study will help researchers better understand:

• How Long COVID affects the brain, heart, and lungs.
• Whether Long COVID can make someone’s chronic (long-term) illnesses worse or lead to the development of new chronic illnesses.
• What makes Long COVID symptoms get better, stay the same, or get worse.

Each RECOVER observational cohort study follows a detailed study plan called a research protocol. These protocols describe the questions researchers will try to answer, what they will do to answer those questions, and how they will work with study participants.

Although each study follows different processes and provides different kinds of information, protocols help ensure that findings from all studies can be combined to help the scientific community understand, diagnose, prevent, and treat Long COVID.

Visit the RECOVER Studies website to view protocols, protocol summaries, and related materials for both phases of the adult observational cohort study and pediatric observational cohort study. 

The infrastructure of the RECOVER Observational Studies Consortium, a large, nationwide network of lead investigators conducting RECOVER-funded research, is made up of 4 cores.

Administrative Coordinating Center (ACC), RTI International. Oversees and supports Consortium communications, work groups, the development of research protocols, and research study implementations. The ACC also shapes how RECOVER engages with caregivers, patients, and community members. Learn more about RTI International’s role.

Biorepository Core (BRC), Mayo Clinic. Receives, manages, and makes available to researchers a diverse range of biospecimens obtained from RECOVER research studies. Learn more about Mayo Clinic’s role.

Clinical Science Core (CSC), New York University (NYU) Langone Health. Oversees the membership and scientific aims of the Consortium. The CSC develops and implements research protocols, manages study recruitment and retention, oversees study procedures across sites, provides oversight on data and biospecimen collection and quality control, leads communications and engagement with study participants, and leads the publication and dissemination of research findings for the observational cohort studies.  Learn more about NYU Langone Health’s role.

Data Resource Core (DRC), Massachusetts General Hospital. Tracks, organizes, and ensures the consistency of all the data collected from the different Consortium studies. The DRC also helps make RECOVER study data accessible and searchable. Learn more about Massachusetts General Hospital’s role.

The RECOVER Observational Consortium Steering Committee (OCSC) provides scientific leadership, operational oversight, and program coordination for observational cohort studies to pursue the scientific goals of the RECOVER Initiative. The roles and responsibilities of the OCSC include the following:

• Oversee the science and operations for all observational cohort studies.
• Monitor progress toward RECOVER milestones to deliver results within timelines and budgets.
• Set up and oversee a team of subcommittees, coordinating committees, and sub-coordinating committees.
• Facilitate and promote collaboration, cooperation, and communication across the RECOVER Observational Studies Consortium.
• Identify, assess, and develop solutions for operational or scientific challenges.