**1. Introduction**

In the last decades, life expectancy in lung transplant recipients (LTRs) has improved. According to data of the International Society of Heart and Lung Transplant registry, including 260 lung transplantation centers with 69,200 adult LTR worldwide, infections remain the leading cause of death within the first year after lung transplantation [1]. Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) has affected solid organ transplant (SOT) recipients as well as immunocompetent patients and continues to claim lives globally. Data on COVID-19 in LTRs are scarce, mostly reported in case reports and small case series. One study reported 17 LTR with COVID-19 in a series of 90 SOT recipients, but the LTR were not analyzed separately [2]. Verleden et al. studied a total of 10 LTR with COVID-19 [3]. Another study performed a telephone survey including 41 LTR with COVID-19 [4].

Surprisingly, with respect to the chronic immunosuppression in SOT recipients, the expected higher incidence and mortality of COVID-19 in this group has not been widely observed. One hypothesis is that the use of calcineurin inhibitors in this group of patients

**Citation:** Hage, R.; Steinack, C.; Gautschi, F.; Pfister, S.; Inci, I.; Schuurmans, M.M. Clinical Characteristics, Treatments and Outcomes of 18 Lung Transplant Recipients with COVID-19. *Transplantology* **2021**, *2*, 229–245. https://doi.org/10.3390/ transplantology2020022

Academic Editor: Brian C. Keller

Received: 19 April 2021 Accepted: 4 June 2021 Published: 15 June 2021

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mitigates the severe hyperinflammation (cytokine storm syndrome) and may thus contribute to less morbidity and mortality. This retrospective study of consecutive LTRs with COVID-19 from the Zurich Lung Transplant Center aims to describe the features of the disease by analyzing the clinical, laboratory and radiology characteristics and the outcome of these patients.

## **2. Methods**
