Trial reportArchives of medical research2022
Efficacy and Safety of Vitamin D Supplementation to Prevent COVID-19 in Frontline Healthcare Workers. A Randomized Clinical Trial.
Trial report in Archives of medical research, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 57 papers, 11 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
57 citing papers in PubMed, 11 syntheses or guidelines pooled it, 100 citations in OpenAlex.
- Vitamin D levels, general health status, and work productivity among healthcare workers-a scoping review of published literature (2010-2025).Frontiers in nutrition · 2026Pooled it
- Vitamin D supplementation to prevent acute respiratory infections: systematic review and meta-analysis of stratified aggregate data.The lancet. Diabetes & endocrinology · 2025Pooled it
- Pooled it
- Pooled it
- Optimal methods of vitamin D supplementation to prevent acute respiratory infections: a systematic review, dose-response and pairwise meta-analysis of randomized controlled trials.Nutrition journal · 2024Pooled it
- Effect of Vitamin D3 Supplementation on Severe COVID-19: A Meta-Analysis of Randomized Clinical Trials.Nutrients · 2024Pooled it
- Pooled it
- Preventive Vitamin D Supplementation and Risk for COVID-19 Infection: A Systematic Review and Meta-Analysis.Nutrients · 2024Pooled it
- Pharmacological evaluation of vitamin D in COVID-19 and long COVID-19: recent studies confirm clinical validation and highlight metformin to improve VDR sensitivity and efficacy.Inflammopharmacology · 2024Pooled it
- The Effects of Vitamin D Supplementation in COVID-19 Patients: A Systematic Review.International journal of molecular sciences · 2022Pooled it
- Prophylaxis against covid-19: living systematic review and network meta-analysis.BMJ (Clinical research ed.) · 2021Pooled it
- Effect of moderate or high versus low dose daily vitamin D on COVID-19 incidence: A double-blind, parallel-group randomized clinical trial.Clinical nutrition (Edinburgh, Scotland) · 2026Trial
- Trial
- Effect of a test-and-treat approach to vitamin D supplementation on risk of all cause acute respiratory tract infection and covid-19: phase 3 randomised controlled trial (CORONAVIT).BMJ (Clinical research ed.) · 2022Trial
- Prevention of covid-19 and other acute respiratory infections with cod liver oil supplementation, a low dose vitamin D supplement: quadruple blinded, randomised placebo controlled trial.BMJ (Clinical research ed.) · 2022Trial
- Vitamin D in Infectious Diseases: A Narrative Review Focusing on COVID-19, Long COVID, and Influenza.Nutrients · 2026Review
- Integrative Vitamin D-Inflammatory-Coagulation Biomarker Index Predicts COVID-19 Severity: Development and Validation of the Vitamin D Inflammatory Burden Score (VDIBS).International journal of molecular sciences · 2026Article
- Serum 25-hydroxyvitamin D concentrations, well being, and presenteeism among hospital porters: a single-center cross-sectional study in Greece.Frontiers in nutrition · 2026Article
- Comparative effectiveness of oral nutritional supplements in preventing respiratory tract infections among adults: a systematic review and network meta-analysis.EClinicalMedicine · 2025Article
- Vitamin D and COVID-19: Clinical Evidence and Immunological Insights.Life (Basel, Switzerland) · 2025Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
16 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundAssociations between vitamin D (VD) deficiency and the risk of SARS-CoV-2 infection have been documented in cross-sectional population studies. Intervention studies in patients with moderate to severe COVID-19 have failed to consistently document a beneficial effect.
objectiveTo determine the efficacy and safety of VD-supplementation in the prevention of SARS-CoV-2 infection in highly exposed individuals.
methodsA double-blind, parallel, randomized trial was conducted. Frontline healthcare workers from four hospitals in Mexico City, who tested negative for SARS-CoV-2 infection, were enrolled between July 15 and December 30, 2020. Participants were randomly assigned to receive 4,000 IU VD (VDG) or placebo (PG) daily for 30 d. RT-PCR tests were taken at baseline and repeated if COVID-19 manifestations appeared during follow-up. Serum 25-hydroxyvitamin D3 and antibody tests were measured at baseline and at day 45. Per-protocol and intention-to-treat analysis were conducted.
resultsOf 321 recruited subjects, 94 VDG and 98 PG completed follow-up. SARS-CoV-2 infection rate was lower in VDG than in PG (6.4 vs. 24.5%, p <0.001). The risk of acquiring SARS-CoV-2 infection was lower in the VDG than in the PG (RR: 0.23; 95% CI: 0.09-0.55) and was associated with an increment in serum levels of 25-hydroxyvitamin D3 (RR: 0.87; 95% CI: 0.82-0.93), independently of VD deficiency. No significant adverse events were identified.
conclusionsOur results suggest that VD-supplementation in highly exposed individuals prevents SARS-CoV-2 infection without serious AEs and regardless of VD status.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.