NIHR Global Health Research Unit on Respiratory Health (RESPIRE)

Hypertonic saline nasal irrigation and gargling for suspected COVID-19

This project is based at the Allergy and Asthma Institute, Pakistan


  • Project title:  Hypertonic saline nasal irrigation and gargling (HSNIG) for suspected COVID-19: pragmatic, web-based Bayesian adaptive randomised controlled trial in Pakistan
  • Based at:  Allergy and Asthma Institute, Pakistan (AAIP)
  • Start date: April 2021
  • End date: November 2021
  • Principal investigator:  Osman M Yusuf
  • Project team:  Aziz Sheikh, Sandeep Ramalingam, John Norrie, Catriona Graham, Aimal Rextin, Shahida Ashraf


COVID-19 has spread rapidly worldwide and is now a pandemic. In the absence of a suitable vaccine, we need a safe and effective treatment that can be used globally.

A previous study (the Edinburgh and Lothians Viral Intervention Study (ELVIS)) found that nasal washouts and gargling with salty water (hypertonic saline) may be helpful in reducing the length of illness in those suffering from the common cold.

It was found that epithelial cells, which line the nose and throat, can create an antiviral effect by producing hypochlorous acid (HOCl) from chloride ions supplied via the salt. HOCl is the active ingredient in bleach. Epithelial cells therefore have a natural antiviral immune mechanism that appears to works across a number of virus types, including coronaviruses.

In COVID-19, high levels of the coronavirus SARS-CoV-2 are detectable in the upper respiratory tract of asymptomatic and symptomatic individuals. It is suggested that nasal washout and gargling with salt water may have a role to play in reducing symptoms and the duration of the COVID-19 illness, as well as helping to reduce transmission of the virus.

Aim and impact

This project will evaluate whether hypertonic saline nasal irrigation and gargling is effective in reducing the duration of illness in those with clinically suspected or confirmed COVID-19 being managed in the community.

If found to be effective, this homemade, inexpensive, safe and scalable intervention will have the benefits of reducing the severity and length of illness and reducing household transmission.

This work will feed directly into national and international decision making in relation to the management of community-based management of those with mild suspected/clinically confirmed COVID-19. 

Key developments

Project website

COVID-19 Nasal Wash Study

Project data

Download the project Data Management Plan