The CDC calls them breakthrough infections and we don't know exactly how many of these cases there are, but data from states suggests it's in the thousands.
"I was like, 'oh my God.' I couldn't believe it," Melanie Rosen said. "I thought I was like Teflon."
The Valley Stream woman got her second dose of the Moderna vaccine in Queens on February 20th and then one month later tested positive for COVID-19.
She was so confident after getting vaccinated, she decided to visit with eight friends and didn't wear a mask, but none of them were vaccinated.
While she may never know if that's how she caught COVID-19, three of those friends also tested positive.
Rosen can't turn back her clock, but she is hoping others hear her story and make more guarded decisions.
"I'm telling you, be careful because I hung out with eight people who were like family members and you could bring some elderly into your home and they could get COVID-19 with the shot," Rosen said.
While Rosen's situation is rare, what's more common right now is people testing positive for COVID-19 in between their two vaccine doses
That's what happened to Eyewitness News reporter Stacey Sager.
Fortunately, her case was mild, presumably because she had the first Pfizer dose.
The same was true for 38-year-old mom Alissa Zulvergold.
She and her two-year-old tested positive in Manhattan while she was still awaiting her second dose of the Moderna vaccine.
That had her debating whether or not to delay the next dose.
"I currently don't feel sick. I'm planning on getting it, but I'm thinking about making a game-day decision," Zulvergold said.
Experts say research shows that the second dose is still effective even if it's a little late as long as you've recovered from COVID-19.
"Once you're out of quarantine, so usually, that's 10 days after the initial onset of symptoms, then you can proceed, and get that second dose," Northwell Health Infectious Disease Specialist Dr. David Hirschwerk said.
The only exceptions are those who've had plasma or monoclonal antibody treatments, they have to wait at least 90 days.
The bottom line is being fully vaccinated is best, even in Rosen's case.
"One can extrapolate that had she not gotten vaccinated she could've gotten a much more severe case of it," Huntington Hospital Northwell Health Dr. Adrian Popp said.
It may not stop you from getting COVID-19, but hopefully, it saves you from a severe case or even death.
MORE: What does it mean if you've had the J&J vaccine?
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