Michigan data shows fully vaccinated people have been hospitalized and died with COVID-19

Just days after getting the Johnson & Johnson vaccine, Melissa Mann says she came down with COVID-19.

"I can’t regulate my body temperature. I had a cough, splitting headaches. The fatigue is unbelievable," Mann, a DeLand resident, said.

She hadn’t gotten the full effect of the vaccine yet. Experts say that takes two weeks. But, it’s a reminder that a shot does not mean you’re safe.

"The CDC obviously has state health departments all on the alert for breakthrough infections," said Dr. William Schaffner, of Vanderbilt University Medical Center.

Breakthrough infections are when fully vaccinated people get the virus.

Some new data out of Michigan is causing concern. The state says out of 1.7 million fully vaccinated people, 246 people tested positive for COVID-19 14 days after getting their second dose. Eleven people were hospitalized and three people over 65 died.

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Experts say the virus variants and how fragile a person’s health was before receiving the vaccine could be playing a part.

"Are they indeed people who were so frail, who had immune systems that were already compromised that their bodies couldn’t take advantage of the vaccine the way the average person can?" Schaffner asked.

The University of Florida (UF) says this hasn't been the case for them.

"We’ve not had severe illness or hospitalization post-vaccine in the thousands of people that we vaccinated in our town and surrounding areas," said Dr. Kartik Cherabuddi, an infectious disease specialist at UF Health.

UF Health will be taking part in a nationwide study where researchers will track young people after they are vaccinated to see if they contract COVID or spread it.

In the meantime, the message from doctors remains: The vaccine is extremely effective, but don’t let your guard down.

Tune in to FOX 35 Orlando for the latest Central Florida news.