Background. Nebulised therapy is the mainstay for treating obstructive airway diseases, but there is heightened particular concern about the potential risk for SARS-CoV2 transmission during nebulisation in COVID-19 patients.

Aim. To ascertain the effects of 0.9% saline nebulisation on SARS-Cov2 spreading in COVID-19 patients.

Methods. Twelve (6 females, mean age 634 yr) COVID-19 inpatients completed pre- and post-nebulization runs. In 5 out of the 12 patients we also assessed changes in the number of exhaled particles after saline nebulisation. Air samples were collected by means of suction pumps equipped with 0.45 PTFE filters and positioned around the patient. Exhaled particles were quantified by using an optical particle counter. Changes in the number of air samples positive for SARS-CoV2 before and after nebulization, as well as in the amount of exhaled particles were assessed by Fisher?s and paired t-test.

Results. Before nebulization, SARS-CoV2 was detected more in the pumps close to the patient than in those far away. Saline nebulization did not significantly change SARS-CoV2 detection. Saline nebulisation induced a marked decrease in exhaled particles in the 2 patients who displayed high particle emission at baseline, whereas no changes were observed in the remaining patients.

Conclusions. Saline nebulisation does not significantly change SARS-CoV2 spreading. Thus, there is no compelling reason to alter aerosol delivery devices for patients with established nebuliser-based regimens.