But a number of experts in communication and behavioral science say that the WHO is certainly not the only one to spoil part of its communication around the pandemic.
On Wednesday, his health secretary, Matt Hancock, struggled to explain why the government is now telling people to wear masks in stores, but not in other indoor spaces, such as pubs and offices.
In the United States, advice on what is and is not safe varies from state to state and from city to city.
Uncertainty
This confusing messaging is a major problem.
The new coronavirus spreads when people interact with each other, so it is crucial to have clear and consistent advice on how to behave, and experts believe that confusion about what to do - and what what not to do - is a major problem that could cause real damage.
Since the virus is brand new, some uncertainty is inevitable. And the advice may have to change over time.
"The changes can lead to confusion and even accusations that experts don't know what they're talking about," crisis communications expert Peter M. Sandman told CNN in an email.
Masks are a good example.
At the start of the pandemic, the shortage of protective equipment for front-line medical personnel was a source of serious concern. Some health professionals also feared that masks could give people a false sense of security and prevent them from following social distancing guidelines.
This is why some public health organizations, including the WHO and the Centers for Disease Control and Prevention in the United States, initially stated that healthy people should not wear masks.
US chief medical officer Jerome Adams even went so far as to say that the masks were "NOT effective in preventing the general public from getting coronavirus".
WHO has taken a similar tone. "There is no specific evidence to suggest that masks by the mass population have any potential benefit," said Dr. Mike Ryan, executive director of the WHO health emergency management program, in March.
But Sandman points to evidence in early February suggesting that infected people who didn't feel very sick passed the virus on in their daily lives in public places. At that time, he said, some experts "at least suspected, even if they could not quite say that they" knew "it with confidence based on evidence," that the masks could help slow the spread. "They certainly had no evidence to say they knew it was not, which they claimed," added Sandman.
As the world learned more about how the virus was transmitted, health authorities and governments were forced to change their guidelines. Earlier this week, the CDC officially told people to wear masks. But this flip-flop has led some people to question the validity of their new advice. Adams himself admitted that it was "very difficult" to correct the message.
There are strategies that leaders can use to minimize the problem, said Sandman - for example, predicting that some changes may be needed as new evidence emerges.
Recognizing the unknown is key to successful communication in a crisis.
"A consistent message is sometimes misinterpreted as:" Let's make a bold statement one way or the other - wear masks, don't wear masks. "But sometimes the message is," We don't have all the information, "said Heidi Tworek, health communications expert and assistant professor at the University of British Columbia.
Tworek said that explaining the rationale for the original mask message would have avoided this confusion.
"In Taiwan, the campaign basically said," Save the [medical grade] masks for healthcare workers. ... So you can have a consistent message that says, "Masks are important and right now they are the most important for healthcare workers and we are still trying to find out if they are effective against this disease", a she said.
Shane Timmons, a behavioral researcher at the Dublin Institute of Economic and Social Research, said there was sometimes a reluctance among experts and politicians to highlight any uncertainty for fear of undermining their expertise.
"But what the evidence actually suggests is that people are very willing to accept uncertainty when it is specified in clear terms. So if you say," These are the things we know, these are the things we don't know, here's how we're going to try to figure it out, "people will take it into account."
Seeming too confident, said Sandman, is "a sin of crisis communication."
The fact that orientation may change as new evidence emerges is not new to academia.
"What makes it very difficult is that the things that usually happen in journals and in small circles of scientists and public health officials - the usual back and forth - are now happening to a global audience" said Tworek.
Although it is the largest public health organization in the world, WHO is a relatively small organization with a limited budget. In more "normal" times, it is mainly aimed at an expert audience. "Her briefings don't usually go to as many people, which creates a very, very different communication environment," said Tworek.
The confusion around the message about masks has caused huge disparities between countries in the willingness of people to wear them - although experts almost everywhere now agree that face covers can help stop the spread of the virus.
An influential American model suggests that if 95% of Americans wore masks in public, it could prevent 33,000 deaths by October 1.
Why do we do what we do?
But even the simplest advice won't work if people question its rationale.
"When people understand why they're asked to do things, they're much more likely to do it," said Susan Michie, professor of health psychology and director of the Center for Behavior Change at University College London.
It shows the advice "don't touch your face" and "wash your hands" as an example.
"It's about preventing the virus that might be on your fingers from entering your body, through your nose, mouth, or eyes ... once people realize that this is how the virus gets into the body, then the eyes, the nose that does not touch and the mouth makes a lot of sense for people. "
One of the biggest problems that policy makers face when communicating the risks of this pandemic is what behavioral economists call the problem of collective action.
For most people, the risk of dying from Covid-19 is quite low. But for the pandemic to end, everyone - even those seen as not at risk - must make sacrifices.
"Clear messages are one of the key factors in determining whether people are willing to cooperate," said Timmons.
There can be different motivations. In the UK, the government has raised the need to protect the National Health Service and save lives. In Ireland, the message was about caring for each other. In some areas of the United States, this is to prevent a further shutdown.
Lead by example
Recognizing the unknown, providing consistent advice and "explaining why" are the key ingredients for a successful crisis communication strategy. But it does not stop there.
"It's about consistency between what you say and what you do. And that's one of the problems ... on the one hand, people say" Oh, it's always a risky situation, be very careful, "and on the other hand, they open pubs," said Michie.
She said public health officials and governments need to improve to get to the points and provide people with a strategy on how to handle the situation.
"Think of it as road safety - we have to do our own risk assessment when crossing the road, for example," said Michie. "Do we always cross the road only at traffic lights or at crosswalks, or do we sometimes cross it somewhere else? If we do, we probably consider several things, such as how far away the cars are, speed travel, are the roads wet, how agile am I? "
One way to help people make decisions would be a simple coronavirus risk calculator that allows users to enter information about themselves to determine the level of danger they face and the situations to avoid, a- she added.
Above all, said Michie, those in authority must lead by example and follow their own rules.
Failure to do so risks further blurring the message - as seen in the United States where President Donald Trump's refusal to wear a mask for months has helped make the issue a political debate rather than a matter of fact.
Michie cites the example of politicians in the UK who "say you have to wear [a mask] when you're on a bus, but we don't need to wear it when we're all crushed together in an interior space in the House of Commons ... the Dominic Cummings [trip] was the pinnacle of that, "she said, referring to a controversial 260-mile car trip by Boris Johnson's chief counselor at the height of the lockdown." us rather than you. "
Photographs of unmasked British Treasury chief Rishi Sunak delivering meals to a recently reopened restaurant - hours after his government told restaurants to make sure their staff are protected - did not go well either more.
Even the clearest advice will never reach its goal if those at the top continue to ignore it.