Aerosol delivery systems for treating obstructive airway diseases during the SARS-CoV-2 pandemic

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes CoronaVirus Disease 2019 (COVID-19), has resulted in a worldwide pandemic and currently represents a major public health crisis. It has caused outbreaks of illness through person-to-person transmission of the virus mainly via close contacts, and droplets produced by an infected person's cough or sneeze. Aerosolised inhaled therapy is the mainstay for treating obstructive airway diseases at home and in healthcare settings, but there is heightened particular concern about the potential risk for transmission of SARS-CoV-2 in the form of aerosolised respiratory droplets during the nebulised treatment of patients with COVID-19. As a consequence of this concern, the use of hand-held inhalers, especially pressurised metered dose inhalers, has risen considerably as an alternative to nebulisers, and this switch has led to inadequate supplies of inhalers in some countries. However, there is no evidence supporting an increased risk of viral transmission during nebulisation in COVID-19 patients. Furthermore, some patients may be unable to adequately use their new device and may not benefit fully from the switch to treatment via hand-held inhalers. Thus, there is no compelling reason to alter aerosol delivery devices for patients with established nebuliser-based regimens. The purpose of this paper is to discuss the current evidence and understanding of the use of aerosolised inhaled therapies during the SARS-CoV-2 pandemic and to provide some guidance on the measures to be taken to minimise the risk of transmitting infection, if any, during aerosol therapies.