• Two randomised controlled trials (n=312, n=22) showed statistically significant improvement in asthma‑related quality of life in people with severe persistent allergic asthma when Airsonett was compared with a placebo device.

  • There was no statistically significant difference in asthma medication usage or exacerbation rates, which were secondary outcome measures in 1 randomised controlled trial.

Adverse events and safety

  • The device is non‑invasive and non‑pharmaceutical.

  • No treatment‑related adverse events were identified.

Cost and resource use

  • The Airsonett device would be added to existing treatment and the average cost of long‑term treatment is £5.72 per day. The estimated cost of an add‑on therapy currently used in NHS practice, omalizumab, is £23 per day.

Technical factors

  • The device is used in the home to deliver cooled and filtered laminar airflow around the user's breathing zone (their nose and mouth). It is powered by domestic mains electricity.

  • The manufacturer provides both maintenance and consumables for the device.