While vaccine products offer an excellent approach to the prevention of COVID-19 disease, emerging evidence has demonstrated that a high proportion of immunocompromised patients, including patients exposed to anti-CD20 therapies, hematopoietic cell transplant recipients, CD19-CAR-T cell recipients, and solid organ transplant recipients, do not develop evidence of humoral immunity to SARS-CoV-2 [19–21]. This evidence concerns the gene CD19 and COVID-19.