Impact of COVID-19 in hematopoietic stem cell transplant recipients: A systematic review and meta-analysis

Background Hematopoietic stem cell transplant (HSCT) recipients are at increased risk of mortality and morbidity with coronavirus disease 2019 (COVID-19) due to severe immune dysfunction. Methods A literature search was performed on PubMed, Cochrane, and Clinical trials.gov from the date of inception to 12/08/2021. We identified 19 original studies reporting data on COVID-19 in HSCT recipients after screening 292 articles. Data were extracted following preferred reporting items for systematic reviews and meta-analysis guidelines. Quality evaluation was done using the National Institutes of Health (NIH) quality assessment tool. Inter-study variance was calculated using Der Simonian-Laird Estimator. Pooled analysis was conducted using MetaXL. A random-effects model was used to estimate the proportions with 95% confidence intervals (CI). Results Of 6711 patients in 19 studies, 2031 HSCT patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were analyzed. The median age of patients was 56.9 (range 1-81.6) years, and 63% patients were men according to 14 studies. The median time from transplant to SARS-CoV-2 infection for autologous (auto) and allogeneic (allo) HSCT patients was 23.2 (0.33-350.5) months and 16.4 (0.2-292.7) months, respectively. The median follow-up time after COVID-19 diagnosis was 28 (0-262) days. The COVID-19 mortality rate was 19% (95% CI 0.15-0.24, I-2 = 76%, n = 373/2031). The pooled mortality rate was 17% (95% CI 0.12-0.24, I-2 = 78%, n = 147/904) in auto-HSCT patients and 21% (95% CI 0.16-0.25, I-2 = 60%, n = 231/1103) in allo-HSCT patients. Conclusions HSCT recipients have a high risk of mortality and clinical complications due to COVID-19. There is a need for ongoing vigilance, masks, and social distancing, vaccination, and aggressive management of SARS-CoV-2 infection in HSCT recipients.