A longer time since last exposure to anti-CD20 Abs is associated with increased seropositivity rates. (A) Hazard ratio (HR) to achieve positive anti-SARS-CoV-2 serology in all patients with B-NHL who were exposed to anti-CD20 Abs is plotted against months from last exposure to anti-CD20 Abs, using a Kaplan-Meier HR curve. (B) HR to achieve positive anti-SARS-CoV-2 serology in patients with a-B-NHL and i-B-NHL who were exposed to anti-CD20 Abs is plotted against months since last exposure to anti-CD20 Abs, using a Kaplan-Meier HR curve.