Nebulization and COVID-19: Is the risk of spread actual?

Abstract

The airborne transmission of SARS-CoV-2 has been quickly suggested based on the stability of SARS-CoV-2 in aerosol for 3 hours. Nebulization, by a possible microorganisms contamination and/or by the aerosolization of contaminated particles, may expose health care workers. Thus, various guidelines on nebulization emerged during the SARS-CoV-2 pandemic to ensure a maximal protection. This study aimed to address the risk of airborne transmission in patients hospitalized with severe COVID-19. Ten severe COVID-19 patients were recruited at the admission in the hospital. They were treated by nebulization with a standard single-use jet nebulizer operating at 8 L/min with a T piece connected to a mouthpiece and a filter. Immediately after the first nebulization, the residual solution of each nebulizer was sampled. Then, the nebulizers were refilled with isotonic saline solution to complete the residual volume. The filter was replaced by a BioSampler® (SKC 20-mL) loaded with 20 mL phosphatebuffered saline and 0⋅5% bovine serum albumin. The nebulizer was driven by a compressed air supply, and a 10min-nebulization was performed again on the bench. The emitted aerosol was continuously collected during the nebulization. The nominal and emitted dose were sampled. The SARS-CoV-2 viral load was quantified in all samples by RT-PCR. No SARS-CoV-2 RNA was found in any sample for all nebulizations. The result of this study shows no SARS-CoV-2 nebulizers contamination by COVID-19 patients at hospital and does not support the role of nebulizers in terms of aerosol virus dissemination in air. Nevertheless, exhaled virus by the patient itself remains and must be considered independently to the nebulizer.