Long-term follow-up of adult hematopoietic stem cell transplant recipients diagnosed with COVID-19.

e19028 Background: Long-term complications of COVID-19 in hematopoietic stem cell transplant (HCT) recipients are unknown. Recent studies have described short term outcomes of COVID-19 infection post allogeneic (allo) and autologous (auto) HCT. In this study we provide long term follow-up of the outcomes of COVID-19 infection in allo and auto HCT recipients. Methods: We performed a retrospective study of adult patients who have received allo or auto HCT and were subsequently diagnosed with COVID-19 infection between March-December 2020. We summarized patient characteristics, laboratory and treatment data related to COVID-19 infection in these patients. Results: In this study, we provide long-term follow-up of over 7 months. Fifteen patients were identified for inclusion (allo n = 12, auto n = 3). Median follow-up was 7.8 months (range 1.9-10.7) for surviving patients. Median age at COVID-19 diagnosis was 55 years (range 24-77). Most patients were > 1 year out from transplant (allo n = 10, auto n = 1, 73%). Two patients (allo n = 1, auto n = 1, 13%) had undergone transplant within the preceding month. Most allo patients (n = 11, 73%) had received myeloablative conditioning. At the time of COVID-19 diagnosis, 9 allo patients (75%) were on immunosuppression (IS) (n = 7 for chronic graft-versus-host-disease (GVHD); n = 2 for GVHD prophylaxis). Eleven patients (73%) required hospitalization (allo n = 9, auto n = 2). Per the National Institutes of Health definitions of COVID-19 illness severity, 3 patients had critical disease (allo n = 2, auto n = 1, 20%), 5 severe (allo n = 5, 33%), 3 moderate (allo n = 2, auto n = 1, 20%), and 4 mild (allo n = 3, auto n = 1, 27%). All patients with chronic GVHD required hospitalization. Two patients died (allo n = 1, auto n = 1, 13%)—both had critical COVID-19 infections, were > 65 years old, > 3 years out from transplant, and had significant comorbidities. The allo patient was receiving prednisone < 1 mg/kg for chronic lung GVHD at COVID-19 diagnosis. Two allo patients developed either acute GVHD or chronic GVHD exacerbation within 3 months of their infection. One patient developed biopsy-proven acute GVHD (max grade III) 3 weeks after her infection and another patient developed a severe exacerbation of chronic GVHD within 3 months—both continue to require multi-modal IS. The remaining 7 patients with chronic GVHD have been maintained on either stable or tapered IS. Conclusions: Given the effect of COVID-19 infection, its impact on HCT recipients is important to define. The majority of HCT patients who contracted moderate-critical COVID-19 infections in our study were either on IS or had significant comorbidities. Our observational data points to the importance of long-term follow-up in HCT patients. Future studies are needed to delineate whether there is a relationship between COVID-19 infection and GVHD development or exacerbation. The role of vaccination in HCT recipients remains to be explored.