The race to vaccinate Michiganders against COVID-19 continues while health officials are working to track "breakthrough cases."
A breakthrough case is someone who tests positive for COVID-19 more than two weeks after their last dose, meaning they are fully vaccinated against the virus. It's rare and only happens in less than .01% of people.
A breakthrough case is rare, but not unexpected.
Jacob Ellis got both doses of the Pfizer vaccine in January and still contracted COVID-19.
As of last week, there have been at least 334 breakthrough cases of COVID-19, out of more than 2.7 million people who are fully vaccinated.
"I was wondering why I caught it when I was fully vaccinated," Ellis said. "It really kinda freaked me out there."
The Southgate resident is quarantining in his basement. He said his symptoms are mild, including a stuffy nose and sore throat.
"Every vaccine has some breakthrough cases," Beaumont director of infectious disease research Dr. Matthew Sims said. "Actually, to be frank, we're seeing less breakthrough cases than we would've expected."
According to data from the CDC, there have been 7,157 reported breakthrough cases in the U.S. out of 87 million fully vaccinated Americans, working out to less than .01%.
Sims said breakthrough cases depend on two things: your immune system and the amount of virus you're exposed to.
"If you get a really bad exposure, like your sitting in a confined area with someone who's hacking and coughing for a few hours, that's a bad exposure, and it may be enough virus that can break through," Sims said.