Does saline solution kill coronavirus?

Multiple posts on Weibo, Twitter and Facebook shared in January 2020 claim that a top Chinese respiratory expert has told people to rinse their mouths with salt water solution to prevent infection from a new virus outbreak.

The posts were published after a new coronavirus strain was discovered in the central Chinese city of Wuhan, infecting hundreds of people.

The claim is false; the expert’s team said saline would not “kill” the new virus and urged people not to believe or share medically-inaccurate online rumours; the World Health Organization told AFP there was no evidence that saline solution would protect against infection from the new coronavirus.

China has sealed off millions of people near the epicentre of the virus outbreak as the death toll from the pathogen, known by its technical name 2019 Novel Coronavirus (2019-nCoV), reached 26 on January 24, 2020.

Shortly after China confirmed human-to-human transmission in the outbreak of the new SARS-like virus, multiple posts appeared on social media purporting to share “professional advice” from Chinese respiratory expert Zhong Nanshan.

The posts, for example here on Facebook on January 22, 2020, have a traditional Chinese caption saying: “Zhong Nanshan’s brilliant idea on preventing infection”.

Zhong Nanshan is a scientist at the National Health Commission who helped expose the scale of the Severe Acute Respiratory Syndrome (SARS) outbreak that killed hundreds of people in both mainland China and Hong Kong in the early 2000s.

The posts purport to quote Zhong Nanshan as saying: “I suggest everyone rinse his/her throat with diluted saline water before going to hospitals or other public areas, and rinse again upon returning home.

“Here’s the method: Swish a mouthful of diluted saline water in your mouth — tilt your head back and let the salt water come into contact with your throat — slightly open your mouth, breath slowly through your throat, and make a ‘ha’ sound. At this moment, the saline water will slowly move with your breath, spit it out after a few seconds. Repeat the above steps with a second mouthful of saline water, then repeat the whole procedure 3-5 times.

“Since virus or bacteria lurks in the pharynx after first entering through the nasal cavity, diluted saline water can kill the bacteria right away so as to prevent infection.

“During the period of SARS, I promoted the same method among students, supervising and encouraging them to follow. As a result, none of the students in our class was infected.”

The posts claim that the information is a: “Suggestion from Academician Zhong Nanshan. January 21, 2020”

Below is a screenshot of the misleading post:

Similar claims linking the same prevention method to other people or hospitals were posted here, here and here on Facebook, and on Weibo here and here.

All of the claims are false. 

The First Affiliated Hospital of Guangzhou Medical University, where Zhong’s medical team is based, said the claim was medically inaccurate.

This January 22, 2020 Weibo post by The First Affiliated Hospital of Guangzhou Medical University contains an image of the misleading claim, which has been partly covered by two red simplified Chinese characters that read “rumour refutation”.

The post’s simplified Chinese caption translates to English as: “#RumorsRefutation Recently, a rumour circulating online claims: ‘Academician Zhong Nanshan suggests rinsing your mouth with saline water in order to prevent infection’.

“Academician Zhong’s team at our hospital hereby officially refutes the rumour: Saline helps clean the mouth and throat, and is helpful for curing pharyngitis. However, the new coronavirus invades the respiratory tract, which cannot be cleaned by mouth rinsing.

“Secondly, no present findings have suggested that saline water can kill the new coronavirus. Please don’t believe or spread the rumour. Thank you.​​​​”

Below is a screenshot of the hospital’s post:

The World Health Organization also told AFP there was no evidence to suggest rinsing with saline solution is effective in preventing infection.

In an email to AFP dated January 24, 2020, the WHO said: “We have seen no convincing evidence that rinsing one’s mouth with diluted saline water will provide protection from this disease.

“While our understanding of the disease is still evolving, the best advice we can give people right now is to do things like wash their hands frequently, practice good respiratory hygiene (e.g. to cough or sneeze into a tissue or their elbow), avoid contact with sick people, and cook food thoroughly. This will help protect people from this new coronavirus but also a range of other diseases.”