Co-infections during SARS-CoV-2 infection in hematologic patients and cell therapy recipients in the omicron era: a Spanish hematopoietic stem cell transplantation and cell therapy group study

Abstract

Background

Although SARS-Cov-2 outcomes have improved in the Omicron era, the synergistic or additive effects between SARS-CoV-2 Omicron variants and other microbiological agents in adult hematologic patients have been little explored. We aimed to characterize co-infection types, identify risk factors for co-infection and determine co-infection-related mortality in hematologic patients and recipients of cellular therapy with a first episode of SARS-CoV-2 infection in the Omicron era.

Methods

Retrospective national Spanish registry analysis of 692 consecutive patients with hematological disease including receptors of cellular therapy from December 2021 to May 2023.

Results

The co-infection rate was 9% (n = 64), 30% of which were polymicrobial. Bacterial, viral, and fungal agents affected 64%, 30%, and 11% of patients, respectively. Among the microbiologically confirmed agents (n = 82), the most common sites of identification were lower respiratory tract (33%), urinary tract (27%) and bloodstream (17%). Multivariable analysis identified cardiopathy (hazard ratio [HR] 1.69), CAR-T therapy (HR 3.42) and pneumonia (HR 5.54) as conditions associated with co-infection. Considering all-cause mortality at day 180 after SARS-CoV-2 detection, co-infection was associated with lower survival (71% versus 92%). Risk factors at COVID-19 diagnosis for non-relapse mortality (NRM) were co-infection (HR 4.28), age ≥ 64 years old (HR 2.55), active hematological treatment (HR 2.13) and under corticosteroid treatment (HR 3.21). In co-infected patients, the only identified factor increasing NRM was corticosteroid use (HR 3.33) at the time of SARS-CoV-2 detection.

Conclusions

SARS-CoV-2 co-infection are relatively frequent in hematologic patients and cellular therapy recipients in the Omicron era. Patients with ischemic cardiopathy, those presenting with pneumonia and recipients of CAR-T are at a higher risk of developing a co-infection, while co-infection, age ≥ 64 years old, active hematological therapy and corticosteroid treatment showed higher NRM. Improvements in identifying and managing concurrent infections during SARS-CoV-2 are needed to further reduce morbimortality in hematologic patients.