False: Gargling with salt water or drinking Pu’er tea won’t prevent COVID-19 infection

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Messages encouraging people to gargle with salt water and drink Pu’er tea to prevent COVID-19 infection have surfaced again in Hong Kong as the city battles its third wave of cases.

One version spreading on WhatsApp claims the number of infected people in mainland China decreased substantially in the past few days because they “gargle with salt water three times a day and keep drinking water for five minutes after that.”

The message claims salt water or warm water with vinegar will kill SARS-CoV-2, the coronavirus that causes COVID-19. It cites Dr. Wang Shu-ang from Tungs’ Taichung Metro Harbor Hospital in Taiwan as the source of this information, explaining that “the virus will first stay at the throat for four days,” making it possible to kill.

Another message quotes Dr. Chui Shiu-hon from the Chinese University of Hong Kong (CUHK) as saying Pu’er tea can “prevent the virus from growing in the lungs” in an RTHK interview. This message claims the situation in mainland China is under control because people drink Pu’er tea.

These two and similar messages have been proven false by both local and international fact-checking organizations.

Taiwan Factcheck Center (TFC) wrote in January, and again in March, that the coronavirus staying “at the throat for four days” is unsupported. There’s no evidence that rinsing the mouth with salt water (or warm water with vinegar) can kill the coronavirus, according to TFC’s report, which quotes medical professionals including Zhong Nanshan, leader of China’s National Health Commission’s COVID-19 research group.

The doctor quoted in the first message, Wang Shu-ang, is an orthopedic specialist. The medical vice president of his hospital posted a comment on a similar Facebook claim denying Wang’s involvement and said it was “false information.”

Tsang Kay-yan, a specialist in infectious diseases in Hong Kong, told Annie Lab that COVID-19 transmits through droplets and therefore, the virus gets into our body through the respiratory mucosal systems — not only the throat but also eyes, nose and ears.

The World Health Organization also states on their Mythbusters page that there’s no evidence that rinsing the nose with salt water would prevent COVID-19 infection.

The expert quoted to attest the benefits of Pu’er tea in the second message was Chui Shiu-hon, who has two doctorate degrees, one in clinical biochemistry from CUHK and another in Chinese medicine from Hong Kong Baptist University. He does not hold a doctorate degree in medicine as the message claims.

It is true that on March 17 Chui talked about the benefits of drinking Pu’er tea in an RTHK live program, “Fresh Morning” (清晨爽利), where he is a regular guest speaker.

In the second part of the episode (starting from 15:20), he discussed an “unverified” claim purportedly from China’s Center for Disease Control and Prevention that people drinking tea regularly are 95% less likely to be infected by COVID-19, which was found to be fake by TFC in February.

Chui also said research in Taiwan shows black tea and Pu’er tea can help stop the replication of the coronavirus that caused the 2003 SARS epidemic.

According to the Department of Health in Hong Kong, coronaviruses are a large family of viruses that can cause illnesses ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS).

Chui clarified in April that the research does not imply tea is also effective protection against the novel coronavirus causing COVID-19. He also said blocking viral replication is different from a cure.

Despite some scientific findings about potentially effective ingredients in Pu’er tea, Tsang, the infectious disease specialist, told Annie Lab further studies are needed.

“Unless we have a very large scale or a more well-designed study to analyze Pu’er tea, we cannot [reach] any conclusions yet, as far as I know,” he said.

Regardless, some people are trying to sell Pu’er tea on Facebook, advertising its benefits with the claim that it is an antidote for COVID-19.

At the moment there is no known substance that can kill the novel coronavirus in the human body, according to Tsang.