What Covid-19 Vaccine Did You Get? You Probably Don’t Know Its Name.

One reason is that naming requirements set up by the Food and Drug Administration and international health regulators are so complex that settling on what to call a new prescription drug—Covid-19-era aside—usually takes about two years. Few turn out as catchy as Oreos.

The regulatory goal is to make sure patients receive only the drugs prescribed to them. So a new brand name can’t be too similar to an existing one. It can neither mention the drug’s chemical components nor violate any trademark. And it must steer clear of unintended meanings in other languages.

Drugs receiving FDA approval have unique names but are getting tough to pronounce: the rheumatoid arthritis therapy Xeljanz; the prostate cancer treatment Orgovyx; and Evrysdi for spinal muscular atrophy, to name a few.

The letter y is becoming one of the most common vowels in drug names because it provides “a very stark visual differentiation,” said Scott Piergrossi, president of creative at the Brand Institute. The Miami-based company was hired to name the Moderna and Pfizer-BioNTech vaccines, as well as several Covid-19 treatments.

In April 2020, a team from the Brand Institute began working on vaccine names. BioNTech, which developed the vaccine with Pfizer, wanted one to reflect both a sense of community and its groundbreaking use of messenger RNA, the molecular couriers that deliver genetic instructions.

But mRNA sounded a lot like Mirena, the name of a birth control device. It also echoed Moderna, which was developing a rival Covid-19 vaccine.

“Starting off with an mRNA combination could have been a lost cause,” Mr. Piergrossi said. The company spent about six months sifting through a thousand or so candidates. Among them: Rnaxcovi, Kovimerna, Covuity and Comirnaty, the eventual winner.

The Brand Institute uses machine-learning-based computer models to make sure a name is at least 70% dissimilar from another, Mr. Piergrossi said. (The 70% standard was set by an FDA process called the Phonetic and Orthographic Computer Analysis.)

The company screened prospective Moderna and Pfizer-BioNTech vaccine names against the FDA’s database of 36,000 existing names and 90,000 in the European Medicines Agency database. It also checked tens of thousands of words in languages spoken throughout international markets to make sure the names would work around the world.

Brand experts said drug names often take time to catch on. The Pfizer-BioNTech and Moderna vaccines are in their early days—only Pfizer’s is fully approved by the FDA; Moderna’s has emergency-use authorization. “These names will find their place in the pharmaceutical lexicon,” Mr. Piergrossi said

Former FDA officials said the agency began instituting stricter naming guidelines for drugs and vaccines in the mid-2000s, seeking to combat prescription drug mix-ups. Above all, the drug’s name can’t look or sound like another medicine’s. The FDA conducts handwriting tests to make sure the name isn’t easily confused with another when prescriptions are being filled.

“Most people outside of the industry have the same sort of impression, ‘Who knew it was that complicated? I thought you just put up some Scrabble tiles and get yourself a name,’ ” said Mike Pile, managing creative director of Uppercase Branding, which has named prescription drugs.

So far, few people know or bother to use hard-won brand names for Covid-19 vaccines. “There’s already an easier and well understood name—Pfizer,” said Harry Thomas, a physician in Austin, Texas. He found the brand name, Comirnaty, confusing.

Moderna considered more literal names like Covidvax before agreeing on Spikevax, which is meant to invoke the coronavirus’s spike-shaped protein.

Kate Cronin, Moderna’s chief brand officer, said the company loves Spikevax, but it also would have been happy calling it the Moderna Covid-19 vaccine. “But we couldn’t,” she said. “You have to come up with a name, and it has to be a good one.”

Andrew Karre, 43, a publishing executive in St. Paul, Minn., spends many of his days agonizing over book names with authors. He thought Moderna chose a cooler name than Pfizer. Comirnaty, he said, was weak.

When it was time to get a booster, he went with Moderna’s heavy-metal sounding Spikevax, primarily based on his reading of studies that showed positive outcomes. He said the name didn’t hurt, either.

Write to Felicia Schwartz at [email protected]