Recent infection with SARS‐CoV‐2 in donors was associated with a higher incidence of acute graft‐versus‐host disease in recipients undergoing allogeneic haematopoietic stem cell transplantation.

Summary: The global pandemic has resulted in the common occurrence of SARS‐CoV‐2 infection in the population. In the post‐pandemic era, it is imperative to understand the influence of donor SARS‐CoV‐2 infection on outcomes after allogeneic haematopoietic stem cell transplantation (allo‐HSCT). We retrospectively analysed allo‐HSCTs from donors with mild SARS‐CoV‐2 infection or early recovery stage (ERS) (group 1, n = 65) and late recovery stage (group 2, n = 120). Additionally, we included allo‐HSCT from donors without prior SARS‐CoV‐2 infection as group 0 (n = 194). Transplants from donors with different SARS‐CoV‐2 infection status had comparable primary engraftment and survival rates. However, group 1 had higher incidences of acute graft‐versus‐host disease (aGvHD), grade II–IV (41.5% vs. 28.1% in group 0 [p = 0.014] and 30.6% in group 2 [p = 0.067]) and grade III–IV (22.2% vs. 9.6% [p = 0.004] in group 0 and 12.2% in group 2 [p = 0.049]). Conversely, the risk of aGvHD in group 2 was similar to that in group 0 (p > 0.5). Multivariable analysis identified group 1 associated with grade II–IV (hazard ratio [HR] 2.307, p = 0.010) and grade III–IV (HR 2.962, p = 0.001) aGvHD, which yielded no significant risk factors for survival. In conclusion, we preliminarily demonstrated donors in the active infection state or ERS of mild SARS‐CoV‐2 infection were associated with higher incidences of aGvHD in transplants from related donors. [ABSTRACT FROM AUTHOR]