Our research has found that people with vitamin D deficiency are more likely to test positive for COVID-19. Other studies have also found that people with vitamin D deficiency have more severe outcomes of COVID-19. University of Chicago researchers are recruiting people to study if vitamin D supplements can reduce the risk and severity of COVID-19. Participants take daily vitamin D supplements and answer 5 short online surveys about their health over 1 year.

To be eligible, you must be age 18 or older, live in U.S., and not have a health condition that would prevent you from taking vitamin D supplements in this study. You may be eligible even if you have had COVID-19 or received a COVID-19 vaccine.

To check your eligibility and enroll in the study, please click the button below. If you have any questions or need help during the enrollment and survey process, please call a study staff member at 773-834-7408.

Vitamin D is an important immune support, but many people in the US have insufficient levels – especially people who don’t spend much time in the sun, people with dark skin, and people who don’t consume dairy or fish.

Preliminary evidence suggests that maintaining adequate levels of vitamin D may reduce the risk of COVID-19 infection, or reduce the severity of cases that do happen. We don’t know yet if taking vitamin D supplements specifically can prevent COVID-19 infections or reduce their severity, so this study will help us to learn whether that is the case.

For more information, please read our FAQ.