What Breakthrough Infections Mean for COVID Vaccines

As coronavirus cases once again rise in the U.S., experts say breakthrough cases will also go up, but that doesn't mean the vaccines aren't working. "It may be that for the vast majority of vaccinated people who get infected, they just don't make enough virus to infect another person," said Janko Nikolich-Žugich, MD, PhD, an immunologist and professor of medicine at the College of Medicine – Tucson.