The nasal vaccines, administered by a spray, induce immunity in the mucus tissues of the nose and throat—where a COVID infection generally begins. Existing COVID vaccines are all injected into muscle tissue. The antibodies they produce, while effective against the virus, might be less effective than antibodies originating in the nasal passage.

Where a nasal vaccine is highly optimized for a respiratory virus like COVID, a pan-coronavirus takes the opposite tack. It aims to be universal rather than specific. “The best solution is a universal pan-COVID vaccine,” Bortz said.

The rationale is that there are lots of coronaviruses besides SARS-CoV-2. There are even scientists who argue that the latest Omicron subvariants are so highly evolved that they should qualify as a brand-new coronavirus. “There are sublineages of Omicron that are already immunologically distinct,” Bortz said.

A vaccine that works against all or many coronaviruses could get ahead of the mutations in any particular pathogen. The upside is that a single vaccine, periodically boosted, could offer some protection against the current COVID pandemic and the next one. The downside is that any universal COVID vaccine might be less effective than a vaccine tailored for a specific coronavirus. Jack of all trades, master of none.