Governments and medical officials are scrambling to provide the public with accurate and timely information about the novel coronavirus. But those efforts are being undermined by the spread of medical misinformation and fake cures on one of the world’s most popular messaging platforms.

WhatsApp, which is owned by Facebook (FB), is coming under renewed scrutiny over how it handles misinformation as the coronavirus pandemic rampages across the globe, infecting more than 200,000 people and killing over 8,000, according to figures compiled by Johns Hopkins University.

The platform is being used to spread messages that often contain a mixture of accurate and misleading claims that have been debunked by medical experts. The problem is now so acute that world leaders are urging people to stop sharing unverified information using the app.

“I am urging everyone to please stop sharing unverified info on WhatsApp groups,” Irish Prime Minister Leo Varadkar said Monday on Twitter. “These messages are scaring and confusing people and causing real damage. Please get your info from official, trusted sources.”

The misinformation often arrives on smartphones in messages that have been forwarded by a friend or relative and includes information purportedly from a prominent doctor or a friend of a friend who works in government. Many of the messages mix sound advice, such as how to wash your hands properly, with misinformation. One false claim that is circulating: drinking warm water every 15 minutes will neutralize the coronavirus.

Because WhatsApp messages are encrypted in a way that allows them to be seen only by the sender and recipient, public health officials and watchdog groups are struggling to track the spread of coronavirus misinformation. WhatsApp itself does not monitor the flow of messages on the platform.

“It is clear … that a lot of false information continues to appear in the public sphere. In particular, we need to understand better the risks related to communication on end-to-end encryption services,” European Commission Vice President Věra Jourová, who oversees the bloc’s efforts to fight disinformation, said in a statement Tuesday.

WhatsApp says it has taken steps to curb misinformation, it is donating to fact-checking groups and users can forward messages to special accounts that can verify the information.

“There are over a dozen [local fact checkers] so far, and we want more to be able to do their important work so rumours are identified and countered,” Will Cathcart, the head of WhatsApp, said Wednesday on Twitter.

WhatsApp is promoting the fact-checking organizations and health ministries on Facebook, with free and special clickable ads that pull up a new WhatsApp chat with the corresponding organization.

Jourová welcomed the new measures but suggested more needs to be done to address the issue of misinformation.

“WhatsApp has informed the Commission about some measures it put in place to limit the spread of disinformation, but most of the problematic content seems to be the so-called organic content, i.e. generated by users themselves,” she said.

Misinformation spreads

In recent days, experts has seen multiple versions of a message with information purportedly from medical professionals concerning four young people infected with coronavirus who had been taking anti-inflammatory drugs.

In one version, written in English, the young people are hospitalized in Cork, Ireland. In another, written in Hebrew, they are in Toulouse, France. Medical officials in both cities have dismissed the story of the four young people as fake.