How important is a slogan during a global health crisis like the one we'e experiencing with COVID-19? More important than you might think.

Consider, for example, what happened in mid-May when the UK government abruptly changed its official COVID-19 slogan.

On March 23, when restrictions on businesses and public life first went into effect, the government produced posters and TV advertisements with a clear three-part directive: Stay home, protect the NHS [National Health Service], save lives.

The slogan was based on the World Health Organization's even simpler "Stay home, save lives"; the red accent color signaled high alert.

Then, on May 10, along with announcing an easing of some restrictions, Prime Minister Boris Johnson unveiled a revised slogan, bordered in go-ahead green. It did not go over well.

What did "Stay alert" mean? How could "alertness" "control the virus"? No one could explain. Survey respondents told a public-relations consultancy the new slogan was "vague," "ambiguous," and "just meaningless drivel." In a tweet, Harry Potter author J.K. Rowling asked, "Is Coronavirus sneaking around in a fake moustache and glasses? If we drop our guard, will it slip us a Micky [sic] Finn?" And a Twitter user called Olaf Falafel posted a slogan generator with absurd variations on the official wording.

In other words, at a time when clear communication was literally a matter of life and death, the UK government fumbled.

It didn't have to be that way. Some COVID slogans have been well crafted and memorable. And past public-health campaigns show how the right slogan can educate and motivate.

"Stamp out tuberculosis"

The earliest public-health campaigns focused on tuberculosis, which in the 19th century and much of the 20th was the leading cause of death in the United States. Early-20th-century advertising simply reminded people not to spit in public. (Scientists had recently discovered that the tuberculosis bacterium could survive in spit for as long as a day.) In 1907, an American Red Cross worker named Emily Bissell launched the Christmas Seal campaign; more than a century later, Christmas Seals are still the official source of revenue for the fight against TB. Many slogans were used over the years, but "Stamp out tuberculosis," as seen in this 1924 poster, was one of the most persuasive. It's an effective use of wordplay that hinges on the noun and verb meanings of stamp. Paired with an image of Santa Claus who looks like he's warning kids not to be naughty, this short slogan packs a powerful punch.

Via National Institutes of Health

"Coughs and sneezes"

Rhyme is a proven mnemonic device — for examples, see my column on ads that rhyme — and one of the most durable public-health slogans was a short verse: "Coughs and sneezes spread diseases." It was first used in the United States during the 1918–1920 influenza pandemic.

But it was in the UK, where it was popularized during World War II, that the slogan became … well, infectious. Cartoons by H.M. Bateman leavened the message without diminishing the warning.

The slogan was also used in short public-service films, first by the Ministry of Health and, after the war, by the National Health Service. Decades later, the World Health Organization included it in a short animated film. And the slogan returned to the US in a 1986 episode of the "Thomas the Tank Engine" children's television show, in which two characters mishear "diesel" as "diseasel" and insist that "coughs and sneezles spread diseasels."

"Silence = Death"

The most famous public-health slogan of recent decades, "Silence = Death," took a dramatically different approach from other awareness campaigns. It was created in 1987 as a response to the growing HIV/AIDS epidemic, which had been ignored by the Reagan administration (or treated as a joke). Avram Finkelstein, a member of the collective that developed the slogan, later wrote that the poster needed "to stimulate political organizing in the lesbian and gay community, and to simultaneously imply to anyone outside the community that we were already fully mobilized." The pink triangle, which had been used in Nazi Germany to stigmatize homosexuals, was chosen to symbolize genocide. The equal sign, Finkelstein wrote, "signaled the inevitability and certainty of calculus and was perfect branding shorthand."

What about COVID?

For communicators, as with doctors and scientists, COVID-19 has presented unique challenges. So far, there's no cure or vaccine. The official line on prevention has changed as the disease spread: mask-wearing was discouraged, then encouraged or even required. Early on, government agencies couldn't urge people to be tested because there weren't enough test kits. In the US, the coronavirus.gov website offers advice but no clear, unifying call to arms — which is what a slogan is. (The word comes from Gaelic sluagh-ghairm, "battle cry.")

Into the breach have stepped local agencies, businesses, and nonprofits. Some messages have been blunt directives that don't rise to slogan status: Stay home. Wash your hands. Be safe.

Other slogans focus not on the disease itself but on "front-line" workers."Not All Heroes Wear Capes" and "I Stay at Work for You, You Stay Home for Us" take the perspective of medical professionals; &"Out There for Us" focuses on other essential employees. And others emphasize maintaining physical distance, as with the macabre "Six Feet Apart or Six Feet Under" signs I've seen all over. Note the use of archetype ("heroes"), parallel structure ("I stay/You stay") and repetition ("six feet")— rhetorical techniques that grab our attention and stick in our memories.

Still other slogans echo the spirit of "Keep Calm and Carry On" — a slogan coined by the British government in 1939 but never publicized until its discovery in 2000 by the owner of a secondhand bookshop. "Keep Calm" had nothing to do with public health, but its grace-under-pressure tone is finding new resonance today in slogans like "We're All in This Together." (Of course, "we" doesn't necessarily mean "all of us": If you have a mega-yacht, or even a gracious backyard, you're going to ride out a quarantine more comfortably than if you're crammed into a downtown apartment.)

What we are all doing together is searching for language that makes sense of a strange, scary, disruptive experience. Language like this slogan from PassItOn, a project of the Foundation for a Better Life, which creates public-service campaigns that promote "values."

The message on this billboard isn't a witty rhyme. It isn't dramatic, like "Silence = Death." It's simply "Stay Apart. Pull Together" — two verbs, two adverbs — by the images of two smiling women of different generations: Encouraging rather than scolding, friendly rather than dire, it tells us that we're engaged in a team effort, like rowers in a boat. Until the virus subsides or an effective vaccine is developed, this may be the best life-saving advice we can hope for.