• 93% of 28 vitamin D treatment studies report positive effects (15 statistically significant in isolation).• Random effects meta-analysis with pooled effects using the most serious outcome reported shows 78% and 53% improvement for early treatment and for all studies (RR 0.22 [0.12-0.39] and 0.47 [0.37-0.60]). Results are similar after restriction to 25 peer-reviewed studies: 83% and 55% (RR 0.17 [0.07-0.42] and 0.45 [0.35-0.59]), and for the 16 mortality results: 78% and 63% (RR 0.22 [0.12-0.43] and 0.37 [0.24-0.57]).• Late stage treatment with calcifediol/calcitriol shows greater improvement compared to cholecalciferol: 80% versus 48% (RR 0.20 [0.13-0.31] and 0.52 [0.33-0.82]). The only treatment study reporting a negative effect is a very late stage cholecalciferol study.• Heterogeneity arises from many factors including treatment delay, patient population, the effect measured, variants, the form of vitamin D used, and treatment regimens. The consistency of positive results across a wide variety of cases is remarkable.• Sufficiency studies show a strong association between vitamin D sufficiency and outcomes. Meta analysis of the 59 studies with pooled effects using the most serious outcome reported shows 56% improvement (RR 0.44 [0.36-0.53]).• While many treatments have some level of efficacy, they do not replace vaccines and other measures to avoid infection. Only 7% of vitamin D treatment studies show zero events in the treatment arm.• Elimination of COVID-19 is a race against viral evolution. No treatment, vaccine, or intervention is 100% available and effective for all current and future variants. All practical, effective, and safe means should be used. Not doing so increases the risk of COVID-19 becoming endemic; and increases mortality, morbidity, and collateral damage.• All data to reproduce this paper and the sources are in the appendix.

	Improvement	Studies	Authors	Patients
Treatment RCTs	45% [-17‑74%]	5	53	482
Treatment studies	53% [40‑63%]	28	289	25,318
Cholecalciferol treatment	45% [31‑57%]	23	228	17,778
Calcifediol/calcitriol treatment	70% [52‑82%]	5	61	7,540
Treatment mortality	63% [43‑76%]	16	152	9,433
Sufficiency studies	56% [47‑64%]	59	495	32,308