The antibody response after 2 doses of an mRNA vaccine against SARS-CoV-2 is excellent in the general population, but the response is different in recipients of solid organ transplants. For example, we have found markedly attenuated antibody responses in transplant recipients after 2 doses of an mRNA vaccine against SARS-CoV-2 (2). In addition, reports of COVID-19 breakthrough infections in vaccinated transplant recipients have prompted interest in administering additional doses of vaccine.
To describe antibody responses and vaccine reactions in recipients of solid organ transplants who had a suboptimal response to standard vaccination and subsequently received a third dose of vaccine between 20 March 2021 and 10 May 2021.