What Is Breakthrough COVID? Here’s Everything You Need To Know

Over the months since the COVID-19 vaccines have become more widely available to people across the United States, there’s been a dramatic decrease in deaths from the virus. This is good news, because it means the vaccines are doing exactly what they’re supposed to do. And although cases are slowly on the rise again as the summer months continue, it's mostly among unvaccinated people. 

Even so, there are recent reports of what’s known as “breakthrough COVID,” which is when someone who is fully vaccinated gets COVID. However, breakthrough cases broadly are perhaps not the most accurate measure of vaccine efficacy. We should instead focus on cases of breakthrough disease, Céline Gounder, MD, an infectious-disease physician at Bellevue Hospital Center in New York, explained to The Atlantic. By that, she means that it's more useful to look at how cases of breakthrough COVID present, not simply whether or not they exist. And the data shows that vaccines have been highly effective at preventing severe symptoms, serious illness, hospitalizations, and death of people who do contract the virus. 

This is good news — but it might also lead to some confusion about what to do if you’re vaccinated and suspect you might have COVID. “This is going to be an increasing problem,” says William Schaffner, MD, a professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center. “Now that we’re going out and about, there is a bit of a resurgence — even though it’s summer — of respiratory viral illness in the community. So we’re starting to exchange viruses while we’re taking off our masks and getting closer to each other.” He added that we might see more testing in the fall and winter months, which are typically dominated by influenza, as doctors attempt to distinguish COVID from other viruses.

There have been a number of cluster breakthrough cases in recent weeks. For example, the small town of Provincetown, MA has recorded a handful of positive COVID cases following the July 4th holiday weekend, including among fully vaccinated people. The city’s population of both year-round and part-time residents is fully vaccinated, according to the city, but it's also a popular destination for tourists. 

Breakthrough cases are to be expected, and they are nothing to panic about. People experiencing these cases are getting less sick and for shorter periods of time, and that's because all of the current vaccines are highly effective at preventing serious disease. But if you’re fully vaccinated and suspect you might have COVID, Dr. Schaffner suggests calling your healthcare provider.

“Depending on your inclination and that of your healthcare provider, there’s no single right way to do this,” Dr. Schaffner says. “If your symptoms are very mild, they may not come to the sufficient attention for you and your provider to seek a test,” he says. “But there’s some utility in doing that because if you do have COVID infection, one of the recommendations would be for you to quarantine yourself for about a week so you don’t spread it to others.” Dr. Schaffner adds that this is good practice even if you’re fully vaccinated; however, the risk of spreading the virus is also much lower than if you’re unvaccinated.  

These recommendations might look different for people who are elderly, have underlying health issues, or are immunocompromised. In these cases, the individual should get tested so that they and their provider can take steps to prevent an infection from becoming more serious, says Dr. Schaffner. 

Still, he adds, “The best way to prevent [these infections in the first place] is with the vaccine.” It remains the most powerful way to mitigate the spread and development of severe COVID cases.