• 91% of 33 vitamin D treatment studies report positive effects (17 statistically significant in isolation).• Random effects meta-analysis with pooled effects using the most serious outcome reported shows 80% and 42% improvement for early treatment and for all studies (RR 0.20 [0.10-0.37] and 0.58 [0.50-0.67]). Results are similar after restriction to 29 peer-reviewed studies: 83% and 44% (RR 0.17 [0.07-0.42] and 0.56 [0.47-0.67]), and for the 19 mortality results: 78% and 55% (RR 0.22 [0.12-0.43] and 0.45 [0.32-0.64]).• Late stage treatment with calcifediol/calcitriol shows greater improvement compared to cholecalciferol: 80% versus 39% (RR 0.20 [0.13-0.31] and 0.61 [0.45-0.83]).• 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 64 studies with pooled effects using the most serious outcome reported shows 57% improvement (RR 0.43 [0.36-0.52]).• While many treatments have some level of efficacy, they do not replace vaccines and other measures to avoid infection. Only 9% 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	42% [33‑50%]	33	325	46,860
Cholecalciferol treatment	35% [25‑44%]	27	256	39,320
Calcifediol/calcitriol treatment	63% [24‑82%]	6	69	7,540
Treatment mortality	55% [36‑68%]	19	175	9,760
Sufficiency studies	57% [48‑64%]	64	524	34,464