NCT07128069

Can Vitamin D Reduce the Burden of COVID-19?

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 2,093 (actual)
• Sponsor: University of Chicago · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

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.

Conditions

• COVID-19

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Vitamin D 400IU	Low dose vitamin D (400 IU/day)
DIETARY_SUPPLEMENT	Vitamin D 4000IU	Moderate dose vitamin D (4000 IU/day)

Timeline

• Start date: 2020-12-28
• Primary completion: 2025-02-15
• Completion: 2025-02-15
• First posted: 2025-08-17
• Last updated: 2025-12-02

Locations

1 site across 1 country: United States