Doctors explain increases in breakthrough COVID-19 cases

The vast majority of new cases are unvaccinated people, but there's also been an increase in breakthrough cases among vaccinated people.


The number of new COVID-19 cases continues to increase.


The vast majority are unvaccinated people, but there's also been an increase in breakthrough cases among vaccinated people.

Although the number of breakthrough infections continues to go up, health officials said those who are vaccinated are still less likely to get seriously ill, be hospitalized or die.

"We're seeing that people are significantly sicker and much sooner than they were with the original variant," Dr. Kinjal Sheth, chief of critical care at Maryland's Northwest Hospital, said.

Dr. William Moss, of the Johns Hopkins Bloomberg School of Public Health, said those who are older or are immunocompromised are more likely to have a breakthrough infection.

"It's a combination of the time since vaccination and a variant that requires higher levels of antibodies to protect us. That's probably creating this situation where we're seeing more breakthrough infections," Moss said.

He said those infected do get a boost in antibodies, but the Food and Drug Administration will have to decide if those people still need a booster shot.

"I would be surprised if they say people who have been infected after being vaccinated do not need booster doses, but I understand the argument, those people's immune systems have been boosted by an additional exposure to the virus," Moss said.

Moss said those who get breakthrough infections can still spread the virus but are less contagious than the unvaccinated.

"What happens with the vaccinated individual is, though, because their immune system has been trained, they clear that virus more quickly, so they're going to be infectious for a shorter period of time," he said.

And those who are vaccinated will have milder symptoms and are less likely to be hospitalized or die, doctors say.

Sheth said many of their patients who are unvaccinated ask for the vaccine but it's too late.

"One person, before we put her on a life support machine, she told me, 'Make sure my husband gets vaccinated,'" Sheth said.