ABSTRACT
Immunocompromised patients are particularly susceptible to serious complications from infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Two mRNA vaccines, BNT162b2 and mRNA-1273, have been shown to have excellent clinical efficacy in immunocompetent adults, but diminished activity in immunocompromised patients. In this study, we measured anti-spike SARS-CoV-2 antibody response, avidity, and surrogate neutralizing antibody activity in Coronavirus Disease 2019 (COVID-19) vaccinated patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Anti-spike SARS-CoV-2 antibody was present in 89% of AML and 88% of MDS patients, but median antibody levels for were lower than in healthy controls (p=0.001 and p=0.04, respectively). SARS-CoV-2 antibody avidity and neutralizing antibody activity from AML patients were significantly lower than controls (p=0.028 and p=0.002, respectively). There was a trend toward higher anti-spike SARS-CoV-2 antibody levels after mRNA-1273 vaccination. Antibody avidity was greater in patients after mRNA-1273 versus BNT162b2 (p=0.01) and there was a trend toward greater neutralizing antibody activity after mRNA-1273 versus BNT162b2 vaccination.