Association Between Vitamin D Deficiency and Post-Acute Outcomes after SARS-CoV-2 Infection Simple Remedy at Hand for Common Problem Wu et al, used the TriNetX research network of COVID-19 patients between January 1 and November 30, 2022. Patients were matched using propensity score matching (PSM) and divided into VDD (< 20 ng/mL) and control (≥ 20 ng/mL) groups. The primary outcome was a composite of long-COVID, all-cause emergency department (ED) visits, hospitalization, and death during the follow-up period (90-180 days) after the diagnosis of COVID-19. https://open.substack.com/pub/petermcculloughmd/p/association-between-vitamin-d-deficiency @PeterMcCulloughMD .