Table 2

Summary of registered interventional randomised controlled clinical trials of vitamin D (only) in COVID-19

Trial IDScientific titleNationsSizeStatusCompletion dateAim/descriptionPrimary outcome measures (summarised)
NCT 04386850Preventive and Therapeutic Effects of Oral 25-Hydroxyvitamin D3 on Coronavirus (COVID-19) in AdultsIran and USA1500RecruitingMarch 2021Two-armed study looking at the effect of 1000 IU of vitamin D in the prevention of COVID-19 in healthcare workers and their families as well as in patients with a COVID-19 diagnosis and treatment of patients with COVID-19COVID19 diagnosis, severity, hospitalisation, disease duration, death, oxygen support
Randomised Controlled Trial of High Dose of Vitamin D as Compared With Placebo to Prevent Complications Among COVID-19 PatientsArgentina1265RecruitingDecember 2020An RCT comparing one dose of 500 000 IU of vitamin D versus placebo in SARS-CoV-confirmed patients requiring hospitalisation for COVID-19 but not critical care at the time of admission.
  • Respiratory SOFA score (200 patients).

  • Need of a high dose of oxygen or mechanical ventilation (1265 patients).

Improving Vitamin D Status in the Management of COVID-19USA64Not yet recruitingDecember 2020A double-blind RCT assessing the efficacy of vitamin D (1000 IU daily vs 50 000 IU two times per week for the first week then once weekly) in COVID-19 patientsSymptom recovery over 3-week time period
IRCT20200401046909N2Investigating Preventive Effects of Oral 25-Hydroxyvitamin D3 on COVID-19 in Adults: a Randomised, Controlled Double-Blind Clinical TrialIran540RecruitingNot statedA double-blind RCT on adult participants without COVID-19 to determine the effect of vitamin D supplementation (1000 IU/day) on serum levels of 25(OH)D and relate this to decreased incidence of COVID-19Affected by COVID-19 during study (symptoms, CT findings, PCR)
COVID-19 and Vitamin D Supplementation: a Multicenter Randomised Controlled Trial of High Dose vs Standard Dose Vitamin D3 in High-risk COVID-19 Patients (CoVitTrial)France260RecruitingMay 2021Open-labelled randomised study of 400 000 IU of vitamin D as a single dose compared with 50 000 IU of vitamin D in confirmed COVID-19Number of death of any cause, during the 14 days following the inclusion and intervention
Effect of Vitamin D Administration on Prevention and Treatment of Mild Forms of Suspected COVID-19Spain200Not yet recruitingJune 2020An RCT assessing the addition of 25 000 IU of vitamin D in 40–70 year olds who have non-severe symptomatic COVID-19 and who are taking NSAIDs, ACE2 inhibitor, ARB or thiazolidinediones, according to clinician criteria, based on the current recommendations.Composite of cumulative death (ie, mortality) for all causes and for specific causes
EUCTR2020002312-43-ESClinical Trial, PHASE III, Randomised, Open-Label, to Evaluate the Efficacy of Administering High-Dose Cholecalciferol Orally Alongside Standard Therapy in Patients with COVID-19 Pneumonia (COVID-19 HUSO) - Efficacy of High Dose Vitamin D in COVID-19 PneumoniaSpain82UnknownNot statedRCT in vitamin D-deficient (<30 ng/mL) COVID-19 patients with the aim to provide estimates of increased levels of vitamin D levels on days 7 and 14 after high-dose vitamin D treatment (10 000 IU/day) compared with conventional dosing (2000 IU/day)Increased levels of vitamin D will be determined on days 7 and 14 after initiation of treatment
EUCTR2020001960-28-ESEfficacy of Vitamin D Treatment in Patients Diagnosed with Pneumonia Who Require Hospital Admission and Have Vitamin D Deficiency and a Positive Diagnosis for SARS-CoV-2 (COVID-19)Spain108UnknownNot statedRandomised controlled blinded trial of vitamin D in COVID-19-positive patients with vitamin D deficiencyLess serious evolution of respiratory syndrome in terms of mortality and ICU admission
  • ARB, angiotensin receptor blocker; ICU, intensive care unit; NSAID, non-steroidal anti-inflammatory drug; RCT, randomised controlled trial; SOFA, sequential organ failure assessment.