Discussion of 'Breakthrough' COVID Cases Among People Already Vaccinated

Ginger Eatman thought she was safe after getting her second COVID-19 vaccination in February. But she kept wearing her mask, using hand sanitizer and wiping down the carts at the grocery store anyway. A few weeks later, she noticed a scratchy throat.

"By Wednesday morning, St. Patrick's Day, I was sick. I had congestion — a lot of congestion — and some coughing," says Eatman, 73, of Dallas, Ga.

Her doctor thought her symptoms might be allergies. But Eatman started feeling sicker. And then she suddenly lost her sense of smell. ...

So Eatman got tested for the coronavirus. It came back positive. ...

Eatman isn't alone in this experience. It's a long-recognized phenomenon called "vaccine breakthrough."

"Essentially, these are cases that you see amongst vaccinated individuals during a period in which you expect the vaccines to work," says Dr. Saad Omer, a vaccine researcher at Yale University. This incomplete protection that some people experience occurs to some extent with a vaccine against any disease.

"Essentially, these are cases that you see amongst vaccinated individuals during a period in which you expect the vaccines to work," says Dr. Saad Omer, a vaccine researcher at Yale University. This incomplete protection that some people experience occurs to some extent with a vaccine against any disease.

The three vaccines authorized for use against COVID-19 in the United States appear to be at least 94% effective at preventing severe disease and death (starting about two weeks after a person is fully vaccinated), according to data reported so far, and about 80% effective at preventing infection. But that's not 100%, Omer notes, so a relatively small number of infections despite immunization with these very effective vaccines is to be expected.

"So the bottom line is: It's expected. No need to freak out," Omer says. ...