As virus circulates in unvaccinated people, breakthrough cases are expected to grow

Posted at 3:14 PM, Jul 26, 2021

CHICAGO — Thousands of fully vaccinated people have contracted the coronavirus, but experts say these breakthrough cases are rare.

“The total number of individuals who are vaccine breakthroughs is pretty low compared to the number of cases that are out there,” said Dr. Emily Landon, an infectious disease specialist at the University of Chicago Medicine.

But according to Dr. Landon, that risk can easily go up and have far-reaching impacts beyond the person infected.

“The more contact and close contact you have with people who are unvaccinated, the more likely you are to have a breakthrough infection,” said Landon.

As of July 19, the CDC documented nearly 6,000 cases of fully vaccinated people who were hospitalized or died from COVID-19, and 74% of them were 65 or older.

But the agency acknowledges those numbers are under-counted.

In Massachusetts, for example, where 63% of the residents are fully vaccinated, 5,000 breakthrough cases have been reported with 80 deaths.

“Every time someone gets COVID, whether they're vaccinated or not, it gives the virus an opportunity to spread to someone else or to mutate inside their body,” said Dr. Landon.

It’s why vaccination rates matter.

More than 160 million people in the U.S. have already been fully vaccinated, but that’s less than 50% of the total population.

“The more people that are vaccinated, the fewer cases of COVID we're going to see in general and the fewer variants we're going to see emerge,” said Dr. Landon.

And with the more contagious delta variant twice as transmissible, experts warn the more the virus can circulate among the unvaccinated, the more likely the chance of breakthrough cases and potentially vaccine-resistant mutations, which could lead to more spread.

“Any individual who is symptomatic, whether they've been vaccinated or not, should consider themselves to be contagious.”

In the end, experts like Dr. Landon say vaccination is key. But being fully vaccinated doesn’t mean someone is fully protected.

“For people who aren't willing to follow the science, it turns out it might be better for all of us to just wear a mask so that we know that everybody's protected," Dr. Landon said.