The Impact of Portable High Efficiency Hepa Filters on the Incidence of Invasive Fungal Infection in COVID 19 Inpatients in a Tertiary Care Hospital: A Retrospective Analysis from Pakistan

Objective: To identify impact of air filtration on incidence of Invasive fungal infections in COVID-19 patients after restructuring of COVID-19 wards. Study Design: Cross-sectional observational study Place and Duration of Study: This study was conducted at the Department of Clinical Microbiology and Infectious Disease at the COVID-19 ward from June 2021 to November 2021. Materials and Methods: All COVID-19 patients >18 years (non-severe, severe and/or critical) admitted at the tertiary care center were included. Even COVID-19 patients with suspected IPA, based on isolation of fungal species from one or more respiratory samples were included. Two time frames were used for inclusion of patients, one three months prior to and second three months after installation of HEPA filters in COVID wards. Patients with underlying respiratory disease, previous history of invasive pulmonary aspergillosis, on chronic steroid use (>3 months), on broad-spectrum antibiotics and with hematological malignancies were excluded. SPSS version 23.0 was used for data analysis. Results: From 187 patients, 97 enrolled before installation of HEPA filters while 90 after installation of HEPA filters. Overall the mean age of patients was 62.7 ± 14.6 years. A significant difference of p-0.04 was observed in terms of length of stay in-between before installation of HEPA filter group (13.1 ± 11.2 days) and in after installation of HEPA filter group (10.2 ± 8.2 days). Beta-D-Glucan test with HEPA filter was positive in 17 (17.5%) of patients while in 28 (31.1%) of patients without HEPA filter (p-0.03). Treatment with Azoles was found to have significant difference in-between both groups (p-0.002). Overall, treatment was successful in 16 (16.5%) patients in without HEPA filter group while in 38 (42.2%) of patients with HEPA filter (p<0.001) Conclusion: Substantial decrease in incidence of invasive fungal infections among COVID-19 patients was reported in terms of age, length of stay, Beta-D-Glucan, treatment with azoles and overall treatment in favor of HEPA filters.