Tweaked COVID vaccines in testing aim to fend off variants

Dozens of Americans are rolling up their sleeves for a third dose of COVID-19 vaccine -- this time, shots tweaked to guard against a worrisome mutated version of the virus.

Make no mistake: The vaccines currently being rolled out across the U.S. offer strong protection. But new studies of experimental updates to the Moderna and Pfizer vaccines mark a critical first step toward an alternative if the virus eventually outsmarts today’s shots.

“We need to be ahead of the virus,” said Dr. Nadine Rouphael of Emory University, who is helping to lead a study of Moderna's tweaked candidate. “We know what it's like when we're behind.”

It's not clear if or when protection would wane enough to require an update but, "realistically we want to turn COVID into a sniffle,” she added.

Viruses constantly evolve, and the world is in a race to vaccinate millions and tamp down the coronavirus before even more mutants emerge. More than 119 million Americans have had at least one vaccine dose, and 22% of the population is fully vaccinated, according to the Centers for Disease Control and Prevention. Much of the rest of the world is far behind that pace.

Already an easier-to-spread version found in Britain just months ago has become the most common variant now circulating in the United States, one that’s fortunately vaccine-preventable.

But globally, there's concern that first-generation vaccines may offer less protection against a different variant that first emerged in South Africa. All the major vaccine makers are tweaking their recipes in case an update against that so-called B.1.351 virus is needed. Now experimental doses from Moderna and Pfizer are being put to the test.

In suburban Atlanta, Emory asked people who received Moderna's original vaccine a year ago in a...