What is a COVID Breakthrough Case?

You’ve heard the term breakthrough case, but what does it mean? Simply put, it means a person tests positive for COVID-19 after being fully vaccinated. You’re considered fully vaccinated two weeks after the final dose of a COVID-19 vaccine.

As important as vaccines are, they aren’t perfect, and effectiveness may change over time as variants emerge. For example, the Pfizer vaccine was 95% effective at preventing COVID infections in clinical trials, but as the virus mutates, that effectiveness may change. Viruses are constantly changing, so mutations are to be expected -- vaccine developers created vaccines with this in mind. SARS-CoV-2, the virus that causes COVID-19, is part of a larger group of coronaviruses, so researchers have seen many variations of the spike proteins the viruses are named for and have been able to test the vaccines against them.

The good news is that breakthrough infections tend to be mild and have fewer symptoms. Severe cases among vaccinated people are possible, but extremely rare and depend on a person’s underlying conditions and immune system. Currently across the nation, the majority of those hospitalized with COVID-19 are unvaccinated. In Baton Rouge we are seeing vaccines, for the most part, keep vaccinated people out of the hospital. On July 28, there were 248 patients hospitalized with COVID at the three major hospitals in Baton Rouge, and just 35 of them were vaccinated.

This week, the CDC cited emerging evidence that shows the levels of virus found in breakthrough cases among vaccinated people are similar to those found in unvaccinated individuals. That’s important because it means vaccinated individuals could be unknowingly spreading the virus.

U.S. officials are closely tracking data from Israel on the Pfizer vaccine’s effectiveness against the more virulent delta variant and how that could impact the need for booster shots, first for those who are more vulnerable like transplant patients, those with autoimmune diseases or on immunosuppressants.

As the delta variant spreads through our area, please be cautious in public. While studies are under way looking at patterns in breakthrough cases, the data takes time. What you can do right now to keep yourself protected is wear a mask, even if you’re vaccinated. And if you are eligible to get the vaccine, don’t put it off. Schedule your COVID-19 vaccine at brgeneral.org/shot.