On October 21, the Centers for Disease Control and Prevention gave most of the US population permission to get a Covid vaccine booster—a shot in such high demand that 10 million people somehow obtained it in advance of that approval in an effort to feel a little safer. Two days after that, the government of the United Kingdom made things feel a little less safe: It announced the emergence of Delta-plus, a new variant that already accounts for 6 percent of cases in that country, and is even more infectious than the highly transmissible Delta.

Those back-to-back events captured the nauseating pandemic roller coaster: Things are getting better. No, they’re not. Yes, they are. No, they’re definitely not. The endless repetition is exhausting. It has led a loose coalition of scientists to ask: What if we could just make the roller coaster … stop?

In a fistful of papers and preprints published in the past six months, these research teams propose a “universal coronavirus vaccine” that could protect against this entire viral family. That means the current SARS-CoV-2 version, any variants that might escape the protection of existing vaccines, and any future coronavirus strains that might emerge to cause new pandemics.

It is a complex project, and no group is close to reaching the goal. Universal vaccines against other recurrent, genetically variable diseases—see, especially, influenza—have been pursued unsuccessfully for years. But researchers think one for coronaviruses might be more achievable, both because this virus is less genetically complex than the one that causes the flu, and also because the threat of another coronavirus pandemic feels uncomfortably real.

After all, SARS-CoV-2 is the third coronavirus to become a major cause of human disease within two decades, after SARS in 2003 and MERS in 2012. Historic epidemiology suggests there were waves of coronavirus infections in the 20th century, the 19th century, and possibly across millennia. And it’s possible that thousands of not yet identified coronaviruses lurk in bats, wildlife, and domesticated animals, poised for the opportunity to leap between species and trigger havoc.

“This isn’t the first coronavirus pandemic we’ve experienced, and it’s not going to be the last, since in less than 20 years we have encountered three coronaviruses that have pandemic potential,” says Pablo Penaloza-MacMaster, a viral immunologist and assistant professor at Northwestern University, and senior author on several papers outlining approaches to a universal vaccine. “We want to be ready for the next pandemic, and the way to do that is to prepare.”

These research teams aren’t the only ones to feel some urgency working on this. In March, the nonprofit Coalition for Epidemic Preparedness Innovations, a public-private partnership that funnels government and philanthropic money to worthy projects, announced it would commit up to $200 million to support universal coronavirus vaccine research. 

But here’s the challenge: To make a vaccine that protects against multiple types, strains, or variants of a virus, researchers have to find some feature that they all have in common and that our immune system reacts to. Then they have to incorporate that feature into the vaccine. With the flu, for instance, each new strain arrives bearing tiny changes in a feature called hemagglutinin, a hammer-shaped protein on the virus’s surface that binds to receptors on lung cells. Because every hemagglutinin is different—researchers actually subdivide flu viruses based on how divergent these proteins are—the search for a universal flu vaccine has focused on trying to redirect the immune system’s attention from the variable head of the protein to the handle-like, less variable stem.