SARS-CoV-2 antibody testing for transplant recipients: A tool to personalize protection versus COVID-19.

Anti-spike antibody testing has emerged as a powerful tool to assess SARS-CoV-2 vaccine response in solid organ transplant (SOT) recipients, many of whom remain at risk for COVID-19 despite vaccination. Neither the US Food and Drug Administration nor major transplant societies recommend testing antibody responses after vaccination, or its general incorporation into COVID-19 risk stratification. Notably, in December 2021, the American Society of Transplantation recognized anti-spike seronegativity as a consideration for use of monoclonal antibody pre-exposure prophylaxis. In this viewpoint, we narrate the evolving rationale for anti-spike antibody testing and ultimately recommend that all SOT recipients be tested for anti-spike antibody after vaccination. This result should then be used to personalize efforts to improve protection versus COVID-19 for the most vulnerable, such as additional vaccination strategies and consideration of passive immunoprophylaxis.