There have been posts on social media of people advising each other to drink hot water or gargle, to “wash away” coronavirus and prevent infection.

While drinking warm water or gargling may help symptoms if you have a sore throat, there’s no evidence that it will protect against coronavirus infection.

Coronavirus enters the body through the eyes, mouth or nose. When it arrives in these areas, it can get into a cell and start to reproduce. That’s why the best way to protect against the virus is to wash hands with soap and avoid touching your eyes, mouth or nose. Once the virus is in your body, drinking water or gargling is unlikely to help.

Gargling is commonly used in some countries as a way to prevent colds and flu, although there is little evidence that this works.

Where did the story come from?

The New York Times reported that there are many posts on social media asking about gargling as a protective measure.

In some countries in East Asia, gargling is a common practice and widely believed to reduce infection. It was even part of the recommended pandemic influenza response by the Japanese government.

What is the basis for the claim?

There have been no studies looking at whether gargling or drinking hot water, warm water or salted water can protect against the virus that causes Covid-19.

A review of evidence on whether non-medical interventions can help to slow or stop the spread of flu, carried out in 2015, included two trials of oral hygiene carried out in Japan. One looked at weekly dental hygiene appointments and advice from hygienists for elderly people, which found this reduced oral bacteria and signs of infection in saliva. Another compared gargling with water, povidone iodine mouthwash or usual personal care. It found no significant preventive effects for gargling, or for one type of gargling versus the other. The review concluded that “oral hygiene and handwashing [showed] efficacy.”

Experts have challenged the view that drinking water or gargling can “wash away” the virus. Speaking to the BBC website, Professor Trudie Lang, professor of Global Health Research at the University of Oxford, said there is “no biological mechanism” for washing a respiratory virus down into your stomach in order to kill it.

In the US, Dr Amesh Adalja, Senior Scholar researching emerging infectious diseases at  Johns Hopkins Center for Health Security adds: “While it is true that coronavirus can cause a sore throat and gargling with warm water may make it feel better, it has no direct effect on the virus.”

Drinking plenty of fluids and staying well-hydrated is generally good health advice, especially if you become unwell. But there is no reason to think this will prevent you from becoming infected.

What do trusted sources say?

Harvard TH Chan School of Public Health says: “There is no evidence that regularly gargling has protected people from infection with the new coronavirus. While this may help soothe a sore throat, this practice will not prevent the virus from entering your lungs—neither will drinking frequent sips of water.”

Analysis by EIU Healthcare, supported by Reckitt Benckiser

 

Citation

  1. Smith S et al. Use of non-pharmaceutical interventions to reduce the transmission of influenza in adults: A systematic review. Respirology (2015) 20, 896–903 doi: 10.1111/resp.12541 https://onlinelibrary.wiley.com/doi/full/10.1111/resp.12541

Reading list

  1. Pandemic Influenza Preparedness Action Plan of the Japanese Government. Inter-ministerial Avian Influenza Committee Revised October 2007. Available at https://www.mhlw.go.jp/english/topics/influenza/dl/pandemic02.pdf [Accessed 1 April 2020]
  2. BBC News Fact Check Team: Coronavirus: The fake health advice you should ignore. 8 March 2020. https://www.bbc.co.uk/news/world-51735367
  3. Jackie Powder. COVID-19 Myths vs. Realities. Johns Hopkins Bloomberg School of Public Health. https://www.jhsph.edu/covid-19/articles/coronavirus-facts-vs-myths.html
  4. Myths Vs Facts. Harvard TH Chan School of Public Health. https://www.hsph.harvard.edu/india-center/myths-vs-facts/