Does the world really need an Omicron vaccine?

Decision makers are mulling whether a fourth dose of an original vaccine will be useful, or whether boosting people with a vaccine designed specifically against Omicron makes sense. Essential to those discussions are data on the duration of protection that a third dose provides, says Matthew Hepburn, a senior adviser at the White House Office of Science and Technology Policy (OSTP). “In near-real time, we need to sort out how long protection lasts, because the fourth-dose conversation is completely shaped by that,” he says. That means watching the vaccines’ effectiveness against Omicron for several more months…

If Pfizer meets its ambitious goal — just months from strain identification to clinical-trial results — it might still be too late to be useful, says Paul Bieniasz, a virologist at Rockefeller University in New York City. Omicron’s dominance as a variant could be waning by then, Subbarao says.

Such a vaccine might work against the variant that dominates after Omicron — especially if the virus continues on that genetic trajectory. But no one knows how the virus will evolve, Bieniasz says. “All of us should be pretty reticent about predicting what is going to be the best matched vaccine months from now,” he says. Just a few months ago, many researchers predicted — logically, but incorrectly — that the next dominant variant to follow Delta would be a virus like Delta. Omicron, however, is completely different.