The mRNA expression levels of CD38, a major NAD+ degrading enzyme (level normalized to HPRT: 8.80 vs. 0.97; p < 0.001), and nicotinamide mononucleotide adenylyl transferase 1 (NMNAT1; 2.18 vs. 0.85; p = 0.018), nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2; 4.68 vs 0.09; p < 0.001), and nicotinamide mononucleotide adenylyl transferase 3 (NMNAT3; 12.01 vs. 2.81; p = 0.032) were all substantially higher in the COVID‐19 group compared to age‐ and sex‐matched controls. Here, CD38 is linked to COVID-19.