Share your health data and donate blood samples to help researchers understand post-vaccination symptoms

What is this trial?

This research project, called the CLEAR study, is trying to understand why some people develop long-lasting health problems after receiving a COVID-19 vaccine. Researchers will track your symptoms over eight months using questionnaires and will examine your blood and blood vessels to look for specific biological patterns—such as changes in how blood vessels work, blood clotting abnormalities, and signs of inflammation—that might explain what's happening in your body.

Right now, doctors don't fully understand what causes these long-term vaccine-related symptoms or how to diagnose and treat them. This study exists to fill that gap by systematically documenting how symptoms change over time and identifying biological markers that could eventually lead to better diagnosis and treatment options.

Do you qualify?

You likely qualify if…

you are 18 years of age or older
you speak German well enough to complete study questionnaires and procedures
your symptoms started within two weeks after receiving a COVID-19 vaccine and have lasted at least six months
you have not had a confirmed COVID-19 infection after your vaccination
you are willing to participate in an eight-month follow-up period

You likely don't qualify if…

you have a severe cognitive, physical, or psychiatric condition that would prevent you from participating
you currently have active cancer or are taking immunosuppressive medications
you are pregnant or might be pregnant
you have a pre-existing condition (such as ME/CFS, POTS, fibromyalgia, or autoimmune disease) that could explain your symptoms
you had an acute infection—including a mild or subclinical one—around the time of your vaccination

What participation looks like

If you join, you will complete online questionnaires about your symptoms and health every few months over eight months. You will also be invited to in-person visits where researchers will perform non-invasive tests on your blood vessels, take blood samples for laboratory analysis, and examine your blood cells under a microscope. Healthy control participants will complete the same blood and vascular tests to provide a comparison. The study is designed to be as non-invasive as possible, with no medications or experimental treatments involved.

AI-generated summary from trial data · Jun 6, 2026 · Not medical advice

Key details

Sponsor

University of Bern

Collaborators

private practice Cell-Re-Active-Training in Bern, Post-Vakzin-Syndrom Schweiz

Enrollment target

~200 participants

Started

March 2026

Primary completion

June 2026

Age range

18 Years and older

Last updated on clinicaltrials.gov in May 2026.

Contact the research team directly

Reach out to the team running this trial. Response times vary — some teams are faster than others.

Central contact

Mirko Schmidt, Prof. Dr.

Institute of Sport Science, University of Bern, Switzerland

Interested in joining?

Tell us you're interested and we'll help connect you with the research team. We'll walk you through what to expect first — no email needed to get started.

Understanding Long-Term Health Problems After COVID-19 Vaccination

What is this trial?

Do you qualify?

What participation looks like

Trial locations(1 site)