Retrospective study finding that regular bolus vitamin D supplementation was associated with less severe COVID-19 and better survival in frail elderly.
For those receiving regular supplementation:
Adjusted mortality hazard ratio with supplementation HR 0.07, p
Risk of severe COVID-19 with supplementation OR 0.08, p
For supplementation started after COVID-19 diagnosis:
Adjusted mortality hazard ratio HR 0.37, p
Risk of severe COVID-19 with supplementation OR 0.46, p
risk of death, 93.0% lower, RR 0.07, p = 0.02, treatment 2 of 29 (6.9%), control 10 of 32 (31.2%), NNT 4.1, adjusted per study, regular bolus supplementation.
Effect extraction follows pre-specified rules prioritizing more serious outcomes.
Annweiler et al., 11/2/2020, retrospective, France, Europe, peer-reviewed, 7 authors, dosage 50,000IU monthly, dose varies - 50,000 IU/month, or 80,000IU/100,000IU every 2–3 months.