The coronavirus pandemic has seen people practice social distancing and self-isolation to slow down the spread of the virus around the world as no cure has yet been discovered. Does drinking warm water help cure coronavirus?
A rumour about Covid-19 has been spreading – that drinking water regularly and keeping your mouth moist can protect you. Here BBC Future examines the evidence.
Though the coronavirus pandemic started just a few months ago, it has already spawned an abundance of online fables and urban legends about how to evade it. One suggests that drinking water can help to prevent the infection. Here’s why that’s extremely unlikely.
The original posts shared on social media say that we should make sure our mouths and throats are always moist, and drink water every 15 minutes. The logic is that this will help to wash the virus down the oesophagus, so it that it can be killed by our stomach acid.
“This is just so simplistic, I can’t even get my head around it,” says Kalpana Sabapathy, a clinical epidemiologist at the London School of Hygiene and Tropical Medicine.
Sabapathy explains that infections often begin after we’ve been exposed to thousands or millions of viral particles, so sweeping a few down the oesophagus is unlikely to have much of an impact. “One gaping hole in it is the likelihood that you managed to flush all of them down into your stomach,” she says. “You would probably have already got them in your nostrils by then, for example – it’s not fool proof,” she says. And here lies another of the main flaws in the idea. Even if the virus hasn’t already managed to find its way inside the cells of your respiratory tract, it can also get into the body in other ways. While some people might become infected by touching their mouth with contaminated fingers, it can also enter the body by touching the nose or eyes.
As it happens, this is not thought to be the main route of transmission. Instead, the main risk is from breathing in tiny droplets containing thousands of viral particles after a person coughs or sneezes – either when they’re hot-off-the-press or have been lingering in the air hours afterwards.
It’s not yet clear if this is also true for Covid-19. Some patients have been reporting symptoms such as nausea and diarrhoea, and now experts from China are warning that there are signs it can infect the digestive tract. According to one report, more than 50% of people with Covid-19 have the virus in their faeces, where it’s lingering long after it’s been cleared from the lungs.
Perhaps most compellingly, there hasn’t been any research looking into whether drinking water can prevent infection with Covid-19, so this technique is not based on science or fact – just wobbly theory. In fact, the only study that comes close is from 15 years ago.
Sabapathy says that, though telling people to keep their mouths moist and drink water every 15 minutes might sound harmless, it’s important to squash this kind of misleading advice quickly.
The danger lies in the false sense of security that it provides. “People will think that by doing that, they're going to be OK,” she says. “It diverts from the much more important messages.”
The overwhelming evidence suggests that the best approach remains avoiding unnecessary social contact and washing your hands. So her advice is to put down the water and pick up the soap instead.