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Can Vitamin D Reduce the Burden of COVID-19?

Can Vitamin D Reduce the Burden of COVID-19?

Status
Completed
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07128069
Enrollment
2093
Registered
2025-08-17
Start date
2020-12-28
Completion date
2025-12-09
Last updated
2026-08-07

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

COVID-19

Keywords

vitamin D

Brief summary

The purpose of this study is to compare the risks of COVID-19 in individuals from the Chicagoland area and other communities in the United States randomized to low (400 IU/day) versus moderate (4,000 IU/day) dose vitamin D.

Detailed description

This study will recruit 2,000 subjects from the Chicagoland area and across the United States to participate in the study from home. Subjects will be invited to volunteer to participate in the study through a variety of forms of outreach, mainly online (e.g., press releases, news interviews, social media, emails, etc.). The sample size was chosen to have at least 80% power to detect a 20% or larger decrease in the hazard of developing COVID-19 between study arms at p\<0.05, based on an estimated monthly incidence of COVID-19 (3%/month for Black/Latinx persons and 1%/month for White persons) and an estimated fraction of persons already immune but unaware they have had COVID-19 (≤10%). Subjects will take a daily dose of vitamin D and answer surveys about COVID-19 diagnosis and symptoms over 12 months after enrollment. Our overall aim is to compare the risks of COVID-19 in adults at increased risk of COVID-19 randomized to low (400 IU/day) versus moderate (4,000 IU/day) dose vitamin D. Our specific aims are: Aim 1: To compare the risk of developing COVID-19 in adults at increased risk of COVID-19 randomized to low versus moderate dose vitamin D. We hypothesize that moderate dose therapy will reduce rates of COVID-19 compared to low dose therapy because vitamin D will reduce symptomatic infection that prompts testing for COVID-19. Aim 2: To compare COVID-19 outcomes (symptoms, hospitalization, ICU stay, ventilator use, death) in adults at increased risk of COVID-19 randomized to low vs. moderate dose vitamin D. Consistent with several recent observational analyses, we expect higher doses to improve COVID-19 outcomes. Subjects will be asked to complete a web-based survey at intake and at 3, 6, 9, and 12 months after enrollment. The intake survey will collect baseline data on subjects' current medications and supplements, sun exposure, exercise, diet and sleep habits, possible COVID-19 symptoms, other influenza-like symptoms, previous exposures to COVID-19, occupation, demographic information, and risks of exposure. The surveys at 3, 6, 9, and 12 months after enrollment will ask the participant or a proxy whether the participant has had a clinically confirmed diagnosis of COVID-19 and the date if so, ask about rates of study medication adherence, and assess for changes in the intake questions about use of other supplements, sun exposure, diet, exercise, and COVID-19 exposures. If the subject reports to have had COVID-19, we will ask about severity, including symptoms, hospitalization and duration, ICU use and duration, need for mechanical ventilation and duration, and death.

Interventions

DIETARY_SUPPLEMENTVitamin D 400IU

Low dose vitamin D (400 IU/day)

DIETARY_SUPPLEMENTVitamin D 4000IU

Moderate dose vitamin D (4000 IU/day)

Sponsors

University of Chicago
Lead SponsorOTHER
Cures Within Reach
CollaboratorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Intervention model description

2,000-person two-arm, double-blinded randomized controlled trial, with half the subjects randomized to low dose vitamin D (400 IU/day), which will serve as the control group, and half to moderate dose vitamin D (4,000 IU/day)

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes

Inclusion criteria

Subjects are able to participate if they: 1. Are 18 years or older. 2. Live in the United States. 3. Are interested in vitamin D as a potential preventive measure against COVID-19 in which they self-administer a daily dose of vitamin D during the 12-month study period. 4. Are willing to complete self-report measures at 5 time points over the course of 12 months by completing a 15-minute survey at intake via web and 10-minute web-based follow-up surveys.

Exclusion criteria

Subjects are excluded from study participation if they: 1. Report being pregnant, planning to become pregnant, and/or report breastfeeding during the study period. 2. Report a history of chronic kidney disease, including a history of abnormal GFR and/or creatinine. 3. Report a history of hyperparathyroidism. 4. Report a history of increased falls. 5. Report a history of hypercalcemia. 6. Report a history of gastrointestinal absorptive disorders, including having undergone bariatric surgery. 7. Report a history of kidney stones (1 in past year or 2 in lifetime). 8. Report already taking more than 400 IU of vitamin D daily as recommended by their health care provider, excluding multivitamins and excluding supplements that include vitamin D and calcium together. 9. Report taking D2. 10. Report a history of sarcoidosis.

Design outcomes

Primary

MeasureTime frameDescription
Time from randomization to first participant-reported COVID-19 infectionFrom date of randomization to the earliest of either the first participant-reported COVID-19 infection up to and including 365 days after randomization or right censoring up to 365 days after randomizationReported in a post-randomization survey

Countries

United States

Contacts

STUDY_DIRECTORDavid O Meltzer, MD, PhD

University of Chicago

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Aug 8, 2026