# COVID-19 was associated with the complications after allogeneic hematopoietic stem cell transplantation

## TL;DR

This study shows that the severity and duration of COVID-19 affect complications and outcomes after stem cell transplants.

## Contribution

The study links both the duration and severity of COVID-19 to transplant complications for the first time.

## Key findings

- Long-term and serious COVID-19 infections increase risks of poor graft function and mortality after transplants.
- Severe or critical illness is associated with lower overall survival rates in transplant patients.
- Multivariable analysis confirms the impact of infection severity and duration on transplant outcomes.

## Abstract

We aimed to identify the severity and duration of COVID-19 infection on complications after allo-HSCT. Enrolled 179 hospitalized patients with COVID-19 were categorized into long-term infection (> 18 days, n = 90) or short-term infection group (≤ 18 days, n = 89) according to the median duration of COVID-19. The severity of COVID-19 was categorized as asymptomatic infection, mild, moderate, severe, and critical illness according to guidelines of National Institutes of Health. Particularly, severe illness and critical illness were classified as serious infection. Asymptomatic infection, mild illness and moderate illness were classified as non-serious infection. The 150-day probabilities of poor graft function (PGF), cytomegalovirus (CMV) pneumonia and non-relapse mortality (NRM) were significantly higher in long-term infection group. The 150-day probabilities of CMV pneumonia and NRM after COVID-19 were higher in serious infection group. The 150-day probabilities of overall survival (OS) was significantly lower in long-term and serious infection group. In multivariable analysis, the severity of COVID-19 was associated with NRM and OS, and the duration of COVID-19 was associated with PGF. In summary, our data reported that the severity and duration of COVID-19 were associated with several complications and contribute to poor outcomes after allo-HSCT.