Impact of nebulization versus metered-dose inhaler utilization on viral particle dispersion in patients with COVID-19

Background: Conflicting guidance exists regarding the characterization of nebulization as an aerosol-generating procedure and subsequent risk of transmission of SARS-CoV-2 to healthcare workers.

Aim/objective: This study sought to address whether SARS-CoV-2 viral load distribution was impacted by bronchodilator delivery via nebulizer versus metered-dose inhaler (MDI).

Methods: Adults infected with COVID-19 were enrolled and received a single dose of albuterol sulfate nebulized solution (2.5 mg/3 mL via breath-actuated nebulizer with filtered mouthpiece) or albuterol sulfate hydrofluoroalkane inhalation aerosol (90 µg/actuation; two puffs via MDI with spacer) in a randomized crossover sequence. Air and surfaces were sampled at predefined locations within patients' hospital rooms to assess SARS-CoV-2 dispersion over three periods (baseline, MDI, and nebulizer).

Findings/results: Eleven patients received crossover therapy. Six patients had detectable SARS-CoV-2 RNA during one treatment period (n = 3 each for MDI and nebulizer) and one during both treatment periods. No viral RNA was found in the rooms of four (36.4%) patients. Overall, few environmental samples (17/397; 4.3%) contained detectable viral RNA, with no meaningful differences in positivity rate across periods; RNA genome copy numbers were low in positive samples. No correlation between dispersion and patient clinical status or environmental parameters was observed.

Discussion: In this first prospective trial evaluating viral load distribution following use of nebulizer versus MDI in hospitalized patients with COVID-19, low environmental contamination was found regardless of administration method. Findings support the use of either device when needed to treat patients with COVID-19.