Home / Science / Health /  Covid-19 breakthrough can happen after booster in rare cases

A small number of Covid-19 breakthrough cases are beginning to show up among people who got both a full round of vaccinations and a booster shot.

Heather Green received her Covid-19 booster, a third injection of the Pfizer vaccine, at the end of September. A month later, the 47-year-old was surprised to discover during a routine test that her mild allergy-like symptoms were actually from Covid-19.

“I was thankful that I had gotten the booster because this illness is so unpredictable," says Ms. Green, who was tested as part of a voluntary surveillance program at the Philadelphia elementary school where she teaches third grade. Two days later her symptoms were gone, she says.

Boosters are now rolling out more widely across the country. So far, doctors say they are seeing few cases of infections in people who have received a booster. Geisinger, a Pennsylvania-based healthcare provider with more than 1.5 million patients, for example, says that since Sept. 1, 62 out of more than 24,000 positive Covid-19 tests—a rate of about 0.2%—were in people who had received a booster.

Despite low levels of post-booster breakthrough cases now, the emergence of the new Omicron variant has raised questions about how well the vaccines will hold up against it. There is currently little data as scientists race to understand Omicron. The U.S. Centers for Disease Control and Prevention tracks breakthrough cases, but doesn’t break out post-booster infections specifically.

Doctors strongly recommend that patients get a booster. They say the fraction of people who might become infected with Covid-19 despite having received a booster can expect to have milder symptoms and a shorter illness. They are also much less likely to be hospitalized or die than people who aren’t vaccinated.

“I cannot tell you how important I think it is for people to get boosters," says Bruce Farber, chief of public health and epidemiology at Northwell Health in New Hyde Park, N.Y. “That being said, no one can say that getting a booster is 100% effective. Under the best circumstances it boosts you up roughly to where you were right after you got the first two vaccines, which was prior to Delta."

After a booster your protection hovers around 90%, he says. So, about 10% of people with a booster could still get infected.

Dr. Farber says he knows of three patients who had breakthrough cases post-booster, one of whom was immunocompromised. “The good news is they haven’t been very sick," he says.

Data out of Israel has shown that people who receive a booster and come down with a breakthrough infection have a much lower risk of becoming hospitalized or dying.

Dennis Cunningham, system medical director of infection control and prevention at Henry Ford Health System in Detroit, says the health system has seen a few hospitalized patients who received a booster dose. He says the patients tend to be older, typically over age 75, or they have immune impairments, such as cancer.

“I am not seeing healthy people admitted to the hospital if they are vaccinated," he says.

David Wohl, a professor of medicine in the division of infectious diseases at the University of North Carolina at Chapel Hill, says he has heard of one breakthrough infection post-booster in his department. It was in an 86-year-old woman who was asymptomatic and tested positive for Covid-19 when in the hospital for an unrelated reason, he says.

“We’re just not seeing" breakthrough cases in people who got boosters, says Dr. Wohl. “If there was real vulnerability I think we’d see more cases."

Still, some cases are to be expected, he says.

“Even with boosting, it’s not a special force field that magically protects the virus from entering our nose and throat," says Dr. Wohl. “It still can. We’re just really good at getting rid of it quicker."

Heather Wyatt, a 48-year-old in Port Washington, N.Y., got a booster in September after receiving her first two Pfizer shots in March. She has multiple underlying health conditions, including rheumatoid arthritis and asthma.

She says the booster helped her avoid serious complications when she recently became infected with Covid-19. She had flown to Nashville, Tenn., for a friend’s surprise birthday party in mid-November. A few days after she returned, she was diagnosed with Covid-19.

Ms. Wyatt says the illness wasn’t as bad as some previous colds that have evolved into pneumonia. “I didn’t get all the heavy chest stuff," she says. Instead, for two weeks she felt as if she had a flu, with aches and pains, a sore throat and a low-grade fever at night.

“I think had I gotten this not with the vaccine and the booster it would have been significantly worse and I would have been in real trouble," she says.

Subscribe to Mint Newsletters
* Enter a valid email
* Thank you for subscribing to our newsletter.

Never miss a story! Stay connected and informed with Mint. Download our App Now!!

Edit Profile
Get alerts on WhatsApp
My ReadsRedeem a Gift CardLogout