“This virus is going to hang around for another couple of years before the world suppresses it, if we’re lucky,” Fauci told me. “I can’t guarantee that we’ll get a universal vaccine in place for this virus, but certainly we need it for the next one.”
A universal SARS-CoV-2 vaccine may prove necessary to end this pandemic. It’s also possible that the current generation of SARS-CoV-2 vaccines will hold up pretty well, and we’ll require only a basic booster here and there. But even when this particular coronavirus has been suppressed, we’ll still need to find a way to protect ourselves against others that lie in wait.
Thousands of related pathogens are estimated to be circulating among various nonhuman species, and some could make the jump to us at any time. In just the past 18 years, three coronaviruses have caused devastating human diseases (SARS, MERS, and COVID-19). “It’s not a question of if but when another pandemic coronavirus emerges,” Martinez says.
Bjorkman shares this certainty. “This isn’t going to be the last one,” she says. “We’re going to have SARS-CoV-3 and SARS-CoV-4. Everyone said this before the current pandemic. Most of the world ignored them. To do so again would really be burying your head in the sand.”
The technology already exists to create a vaccine that protects humans from many coronaviruses at once. Vaccinating against all of them is a more elaborate challenge than taking on one or a few, but hypothetically possible. The broadest vaccine, though, isn’t likely to come from discovering a single, conserved region of the spike protein that all coronaviruses share, and that also reliably stimulates our immune system. This would be something like finding one spot that will blow up the entire Death Star—a little too easy. But we could find an array of frequently conserved regions that turn up in many coronaviruses.
The act of loading multiple targets into one vaccine is not difficult, according to Bjorkman. The postdocs in her lab can quickly create the proteins at the head of the spike and attach them to nanoparticles. “They’re really easy to make,” she says modestly. The central challenge is in knowing which targets to include and making sure that they stimulate the immune system effectively.
“The real issue is better understanding the universe of coronaviruses,” says Wayne Koff, a biochemist and the head of the Human Vaccines Project. It’s theoretically possible to learn the major changes in the viral genome that make them most likely to spread widely and devastatingly in humans, so that our bodies can develop at least partial recognition of whichever dangerous new coronaviruses may come along: “What we’re especially concerned about are the coronaviruses that we don’t even know about yet.”
Koff believes we can figure out which common features or mutations could allow for such a vaccine, as we understand the coronavirus family tree at a more and more granular level. “If animal ecologists can gather enough data from the field, you create an algorithm to find the ones that have the greatest potential to jump species, and then the ones that would kill people,” he says. In his vision, supercomputing and advances in machine learning and modeling would accelerate the predictive process.