This browser does not support the Video element.
Atlanta - Jim Issa has been directing commercials from his home in Atlanta's Kirkwood neighborhood for the last couple of weeks.
He has been stuck there, isolating, after testing positive for COVID-19.
Issa, who is 50, was infected over July Fourth weekend, while hanging out with six fully vaccinated friends and their 4 children at a lake house.
Months after being vaccinated against COVID-19, Jim Issa of Atlanta experienced a breakthrough infection.
"I felt totally safe with my friends, knowing they were vaccinated," Issa says. "These are very careful people. These are people who mostly did not leave the house for a year. So, we're all very cautious."
Still, 5 out of the 11, including three adults and two children, later tested positive for the coronavirus.
Within a few days, Issa and his 11-year-old daughter were both sick.
AAP: Students, staff should wear masks in schools — regardless of vaccination status
"She felt like she had cold," he says. "She was achy and tired."
His daughter felt bad for about a week, he says.
Two weeks later, Issa is still coughing, although his night sweats and body aches have eased.
"I got chest X-rays," he says. "We thought it might be pneumonia. But, luckily, it's not pneumonia."
The CDC says breakthrough cases are expected because no vaccine is 100% effective against infection.
This browser does not support the Video element.
The Atlanta-based health agency is only tracking severe breakthrough infections that result in hospitalization or death.
As of July 12, 2021, the CDC has received reports of nearly 5,500 fully vaccinated people who have been hospitalized or died from a breakthrough infection.
That is a fraction of the 159 million Americans who are now fully vaccinated.
The Georgia Department of Public Health has confirmed 91 severe breakthrough infections as of July 13, 2021.
Issa is not sure if he and his friends were infected with the highly transmissible delta variant or if a unique set of circumstances left him and the others exposed.
But health officials say the variant is driving a rise infections across the US.
Emory infectious disease physician Dr. Carlos del Rio says each person infected with the delta variant passes the virus on to an average of 8 or 9 others.
Still, Dr. del Rio says, the vaccine is highly effective at preventing severe disease and hospitalization.
"If you're fully vaccinated you are protected with two doses fairly effectively against the delta variant, not perfectly, (but) maybe around 80%," del Rio says. "So, you can still get infected. If you get infected, you're probably going to have like a bad cold, congested nose, sore throat. But, you're not going to get very sick. You're going to do okay."
Dr. del Rio says is not clear whether fully vaccinated people like Issa, who do get infected, can then transmit the virus to others.
"So, my advice is if you're vaccinated, and you get infected, you should still quarantine to avoid transmitting it to others," he says.
Jim Issa still trying to understand how he and his friends got infected, and he's hoping experts can eventually explain what is driving breakthrough cases.
"I just think we need more doctors and scientists explaining to us why the vaccine works and why sometimes it doesn't work," he says.
Dr. del Rio says he is most concerned about those who remain unvaccinated.
"If you are unvaccinated, you need to be concerned about every variant out there," he says. "Because, at the end of the day, if you don't get vaccinated, you will get infected."
WATCH: FOX 5 Atlanta live news coverage
This browser does not support the Video element.
_____
Sign up for FOX 5 email alerts
Download the FOX 5 Atlanta app for breaking news and weather alerts.