Dear Editor,Coronavirus disease 2019 , caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has spread rapidly across the globe, threatening the health and safety of an increasing number of people. It has been shown that the SARS-CoV-2 vaccine is effective in reducing the chance of COVID-19 infection and the severity of the disease. [1][2][3] To control the COVID-19 pandemic, an increasing number of studies are calling for people to receive the SARS-CoV-2 vaccine, 4,5 and the Chinese government is also advocating universal vaccination. Patients with malignant hematologic diseases are mostly immunodeficient, 6 and recipients are immunosuppressed when undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). 7 One report on donorderived vaccination indicated that vaccination could induce antigen-specific immune responses in patients after allo-HSCT. 8 In addition, most COVID-19 vaccines in China, different from prevailing types in other countries, are inactivated SARS-CoV-2 vaccines. Hitherto, there are no reports on whether the vaccine will induce immune responses impacting immune reconstitution, complications, and outcomes of recipients. Therefore, many clinicians and patients in China hesitate to choose a COVID-19-vaccinated person as a donor, which partially inspires us to collect cases of donors who received SARS-CoV-2 vaccination to explore the impact of donor vaccination with SARS-CoV-2 vaccine on recovery and outcomes after transplantation in recipients.From March 2021 to December 2021, we retrospectively collected data on a total of 253 patients who received allo-HSCT at the First Affiliated Hospital of Soochow University, none of them had ever had COVID-19 prior to transplantation, and none of them were vaccinated for COVID-19 before transplantation and during the posttransplant follow-up period. All donors and patients provided written informed consent for the protocol approved by The This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.