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.