Can an ancient Asian remedy help prevent the spread of Covid-19?
A team at the University of Edinburgh is investigating the science behind the ancient practice of nasal irrigation and gargling and whether it could protect public health during Covid-19. We talked to the team’s researchers to find out more.
Anyone who has grown up in India is likely to have come across the ancient practice of cleansing the nasal passage with saltwater to deal with a stuffy nose. Known as jala neti or nasyam the techniques are something many swear by for clearing the common cold. It involves adding salt to boiling water, waiting for it to cool, rinsing the nasal passage with the cooled solution, then gargling and spitting it out. In the early part of the 20th century, gargling was also used as a preventative measure against influenza and other respiratory infections in the West, but this practice has become less common in recent times.
When the COVID-19 pandemic was declared, claims that saltwater gargling could offer protection against the new coronavirus began circulating on social media. This prompted the World Health Organization (WHO) to announce that there was no evidence that this is a preventative measure against the virus. They do however state that there is some evidence that it could help people recover from the common cold.
The team in Edinburgh is now attempting to determine if the technique can be effective against COVID-19 by conducting a large randomised controlled study.
“I’ve used nasal irrigation and gargling for the common cold for around 15 years. Nasal irrigation and gargling covers most parts of the upper respiratory tract infected in the initial stages of a viral infection. It’s a very simple intervention, one we can roll out across the world, if it works for COVID-19. Though a simple procedure it could have quite a significant impact by reducing symptoms and viral shedding, while we wait for a vaccine” says Dr Sandeep Ramalingam, a consultant virologist with the NHS and an Honorary Clinical Senior Lecturer at the University of Edinburgh.
The team began studying the scientific properties behind the technique in 2009 in Professor Juergen Haas’s laboratory. Through their research they identified what sniffing saltwater does to the cells to make it so effective in reducing cold symptoms.
“When you do nasal irrigation and gargling, the salt water initially washes the nasal passage. After that, you are left with a thin layer of saltwater on the cells. We found that the cells absorb chloride ions from the salt water to produce hypochlorous acid, which reduces viral replication within the cell,” Dr Ramalingam explains.
Next, a pilot study – Edinburgh & Lothians Viral Interventions Study (ELVIS) – was started in 2014, to find out if the technique could treat the common cold. Participants were asked to carry out nasal irrigation and gargling at home and monitor and record symptoms. Swabs were collected daily to measure viral shedding in the laboratory.
The majority of participants reported a reduction in their symptoms and a decreased need for over-the-counter medications. There were also fewer colds in their household, suggesting a reduction in transmission. This was supported by the reduction in viral shedding in those who did nasal irrigation.
As coronaviruses were the second most common cause of the common cold in the study, the team examined the data to see if nasal irrigation and gargling was effective against coronaviruses, and found encouraging results. Because saltwater promotes the antiviral effect of cells against different viral types, the team believes that the technique may also be effective against novel viruses.
“There is a need to establish whether saltwater nasal irrigation and gargling is helpful in improving outcomes in patients with COVID-19. By studying its effects through a randomised controlled trial, we hope to provide a clear answer to this crucially important public health question,” adds Professor Aziz Sheikh, Chair of Primary Care Research and Development, and a member of the research team for the study.
The ELVIS COVID-19 study launches this week. Questions this study will seek to answer include to what extent this simple remedy can be advised as a public health measure to relieve symptoms at home and to prevent the spread of the disease.
Do you live in Scotland and have recently started to have COVID-19 symptoms? If these started within the last 48 hours you may be able to help the research team by participating in this new clinical study.
Find out other ways to support medical research for Covid-19
Hypertonic saline nasal irrigation and gargling should be considered as a treatment option for COVID-19 - The Journal of Global Health