# Consistent FFP2-masking as part of reducing viral respiratory infections on medical wards for allogeneic hematopoietic stem cell transplantation

## TL;DR

Wearing FFP2 masks in hospitals reduced respiratory infections in patients receiving stem cell transplants without affecting survival rates.

## Contribution

Demonstrates that consistent FFP2 masking significantly reduces viral respiratory infections in allo-HSCT patients.

## Key findings

- FFP2 masks reduced viral respiratory infections from 20.7% to 2.0%.
- Hospital stay duration decreased by 2.5 days with FFP2 masking.
- Use of diagnostic procedures like CT scans and bronchoalveolar lavage decreased.

## Abstract

Patients undergoing allogenic hematopoietic stem cell transplantation (allo-HSCT) are highly susceptible to infections. The consequent use of masks on wards for allo-HSCT has been controversial in the past decades and was not common before the COVID-19 pandemic. We retrospectively compared incidence and outcomes of viral respiratory infections during allo-HSCT on our specialized ward between 01/2018 and 09/2020 to the era of FFP2 masking between 10/2020 and 10/2022 covering similar seasons of the year. Each group consisted of 150 matched patients. The usage of FFP2 masks reduced the incidence of viral respiratory infections from 20,7% to 2,0% (p < 0.001). This reduced the time on ward from a median of 26 days to 23.5 days (p = 0.002). It also resulted in less use of CT-scans (p = 0.003) and bronchoalveolar lavage procedures (p = 0.057). Median time to proof of infection was 21 days after admission in both groups. No difference was detected in progression free survival, hospital survival or non-relapse mortality (p = 0.78). Our retrospective results indicate that FFP2 masks worn by patients and hospital staff may help to significantly reduce the incidence of viral respiratory infections, including COVID-19, shorten the in-hospital time, and reduce costs without affecting survival.