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

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