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PRevention of COVID-19 With Oral Vitamin D Supplemental Therapy in Essential healthCare Teams (PROTECT)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT04483635
Recruitment Status : Terminated (A premature discontinuation was recommended by the Data Safety Monitoring Board and agreed upon by the principal investigator, because the significantly lower recruitment than planned, in the context of mass vaccination of the target population.)
First Posted : July 23, 2020
Last Update Posted : May 28, 2021
Canadian Institutes of Health Research (CIHR)
Laboratoire RIVA
Information provided by (Responsible Party):
Professor Francine Ducharme, St. Justine's Hospital

Brief Summary:
In this 16-week randomized control study, health care workers will receive a bolus dose followed by a weekly dose of vitamin D or a placebo bolus and weekly dose. This study will test whether high-dose of vitamin D supplementation decreases the incidence of laboratory-confirmed COVID19 infection (primary outcome), reduces illness severity, duration, as well as work absenteeism among health care workers (HCW) in setting at high-risk of contact with COVID-19 cases in high COVID-19 incidence areas.

Condition or disease Intervention/treatment Phase
COVID-19 Dietary Supplement: Placebo Dietary Supplement: Vitamin D Phase 3

Detailed Description:

Design. A 16-week triple-blind, placebo-controlled parallel-group, randomised trial of high-dose vitamin D supplementation compared to placebo in health care workers (HCW).

Subjects: HCW caring for individuals at high-risk of infection (i.e., COVID-suspected or confirmed cases) will be randomly allocated in a 1:1 ratio in variable block size to: Intervention-1 oral loading dose of 100,000 IU vitamin D3 + 10000 IU weekly vitamin D3 or Control-identical placebo loading dose + daily placebo. Follow-up: 2 (randomisation and end-of-study) virtual or in-person visits with weekly reminders, brief health and work-status questionnaire.

Randomisation/allocation concealment: Randomisation will be implemented using a computer-generated random list stratified by regions; health care workers will be allocated (1:1) using permuted block randomisation to enhance concealment.

Sample size: A total of 2414 healthcare workers will provide 80% power to detect a 20% reduction in the risk of laboratory-confirmed COVID-19 infection. Given uncertainties in the infection progression, a Bayesian adaptive design is used where the posterior probability of effectiveness is the basis of inference and decision making, for study continuation or termination.

Procedures. Use of remote or in-person randomisation and/or end-of-study visits and remote documentation of outcomes via electronic communication, mailing of biological samples, and external databases will facilitate enrolment, monitoring, and retention of motivated HCW in this high-intensity trial.

Data analyses: An intention-to-treat analysis will be carried out on all randomized participants. Efficacy and safety analyses will be performed under allocation concealment with unblinding occurring after trial completion and analysis of primary outcomes.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 34 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: Parallel-group, placebo controlled trial of vitamin D3 supplementation
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Masking Description: The Laboratoires Riva will provide the active vitamin D3 and placebo pills, identical in appearance, which will be pre-packaged in coded 60-pill bottles. A web-based randomisation system will allow the research personnel (RP) to log in, obtain a randomization number, and dispense study drugs, pre-prepared by the Central pharmacy, in masked kits.
Primary Purpose: Prevention
Official Title: PROTECT RCT (PRevention of COVID-19 With Oral Vitamin D Supplemental Therapy in Essential healthCare Teams
Actual Study Start Date : February 8, 2021
Actual Primary Completion Date : May 4, 2021
Actual Study Completion Date : May 25, 2021

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Placebo Comparator: Placebo

10 placebo tablets taken orally at baseline, followed by 1 placebo tablet once a week for 16 weeks

Note that the study may be prolonged according to the overall infection rate monitored monthly.

Dietary Supplement: Placebo
Weekly oral dose of placebo

Experimental: Vitamin D3

10 tablets containing 10,000 IU (total : 100,000 IU) of Vitamin D3 taken orally at baseline, followed by 10,000 IU once a week for 16 weeks.

Note that the study may be prolonged according to the overall infection rate monitored monthly.

Dietary Supplement: Vitamin D
Weekly oral dose of Vitamin D
Other Name: cholecalciferol

Primary Outcome Measures :
  1. Change in incidence of laboratory-confirmed COVID-19 infection [ Time Frame: 16 weeks ]
    documented by salivary or NP samples obtained clinically for screening or diagnostic purposes throughout the study period, self-obtained salivary samples at endpoint, analysed by RT-qPCR or COVID-19 seroconversion at endpoints

Secondary Outcome Measures :
  1. Distribution of disease severity [ Time Frame: up to 16 weeks ]
    5-category ordinal variable [asymptomatic, mild (managed at home); moderate (hospitalisation without supplemental oxygen; severe (oxygen supplementation); critical (mechanical ventilation/death)

  2. Duration of symptoms in COVID-19 positive participants [ Time Frame: up to 16 weeks ]
    For asymptomatic positive COVID-19 participants, symptoms will be recorded in a daily diary up to 14 days. Symptomatic positive COVID-19 participants will record their symptoms in a daily diary up to 48 hours after the resolution of symptoms

  3. Number of participants with COVID-19 positive IgG serology [ Time Frame: 16 weeks ]
    SARS-CoV-2 IgG Diasorin on Liaison XL platform

  4. Number of workday absences due to COVID-19 suspected/confirmed infection [ Time Frame: 16 weeks ]
    Participant-reported; reported by Direction of Human Resource (or for physicians, Direction des services professionnelles) databases

  5. Number of workday absences for any reason [ Time Frame: 16 weeks ]
    Participant-reported; reported by Direction of Human Resource (or for physicians, Direction des services professionnelles) databases

  6. Adverse health events [ Time Frame: 16 weeks ]
    Number and distribution of adverse health events

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years to 69 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • are aged ≥18 and <70 years old;
  • licenced to practice in Quebec;
  • working or scheduled to work over the next 16 weeks in a setting at high-risk of contact with COVID-19 infected individuals, particularly (but not only) those involved with aerosol generating medical procedures in hospitals and/or caring for patients in long-term care facilities;
  • working in high COVID incidence areas;
  • covered by the RAMQ for medical services and hospitalisations;
  • has a personal email or phone (to which to send every two weeks a reminder and questionnaire by email or text messages);
  • has a fixed address (to which to send the material) in the greater Montreal or surrounding areas.

Exclusion Criteria:

  • vitamin D supplementation >400 IU/day or >12,000 IU/month in past 3 months;
  • intention to take >400 IU per day during the study period;
  • suspected or previously documented COVID-19 infection;
  • history of nephrolithiasis, hypercalcemia, hyperphosphatemia, hyperparathyroidism, granulomatosis disease (e.g., tuberculosis, sarcoidosis), renal impairment/failure, or active cancer;
  • use of any of the following medications: lithium, teriparatide, or digoxin;
  • anticipated prolonged absence from work during the study period (i.e., pregnancy);
  • enrolment in a concurrent randomized trial;
  • has received a vaccine against COVID-19.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04483635

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Canada, Quebec
Montreal, Quebec, Canada, H2W 1T8
CHU Sainte-Justine (CHUSJ)
Montreal, Quebec, Canada, H3T1C5
Sponsors and Collaborators
St. Justine's Hospital
Canadian Institutes of Health Research (CIHR)
Laboratoire RIVA
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Principal Investigator: Francine M Ducharme, MD St. Justine's Hospital
Principal Investigator: Cecile Tremblay, MD CHUM
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Responsible Party: Professor Francine Ducharme, Principal Investigator, St. Justine's Hospital
ClinicalTrials.gov Identifier: NCT04483635    
Other Study ID Numbers: MP-21-2021-3044
First Posted: July 23, 2020    Key Record Dates
Last Update Posted: May 28, 2021
Last Verified: May 2021

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Professor Francine Ducharme, St. Justine's Hospital:
Vitamin D
Primary prevention
Health care workers
Additional relevant MeSH terms:
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Respiratory Tract Infections
Pneumonia, Viral
Virus Diseases
Coronavirus Infections
Coronaviridae Infections
Nidovirales Infections
RNA Virus Infections
Lung Diseases
Respiratory Tract Diseases
Vitamin D
Physiological Effects of Drugs
Bone Density Conservation Agents
Calcium-Regulating Hormones and Agents