A Goldilocks Model for Yearly Covid Vaccinations

Two doses? Three? More? The euphoria that greeted safe and effective Covid-19 vaccines a year ago has turned to confusion and debate in the face of resurgent cases and an ugly new variant. The rich world is doubling down on booster doses, ignoring warnings from the World Health Organization that this will worsen supply shortages in the developing world.

The firms that brought us the mRNA marvels — Moderna Inc. and Pfizer Inc. — aren’t sure of much, except for one thing: It doesn’t look like the need for shots will stop anytime soon. Moderna Chief Executive Officer Stephane Bancel warned vaccines might need retooling next year against the omicron variant, while CEO Albert Bourla of Pfizer has mooted a course of jabs every year to maintain a “very high level of protection” over time.