NEW YORK (CBSNewYork) — Getting vaccinated didn’t prevent a Brooklyn woman from contracting COVID-19.

While there are concerns and confusion around the COVID vaccine, experts say there are a number of reasons why someone can become infected even after getting a shot.

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Ashley Allen, like millions of others, now holds a vaccine card. She got the Johnson & Johnson shot on March 10.

“That’s just the vaccine I wanted to do. Seemed easy. One shot and done,” Allen, 31, told CBS2’s Jenna DeAngelis.

Allen said it was easy, despite experiencing 24 hours of common symptoms.

Three weeks later, she had a cough and fatigue, which she thought was Lyme Disease after spending time upstate.

“I didn’t think of COVID, at all,” Allen said.

Two rapid tests and a PCR confirmed it was the coronavirus.

“I just couldn’t even believe it,” Allen said.

She was especially surprised because, after her shot, she continued to take safety measures, like wearing a mask.

“Just because you have a vaccine, doesn’t mean you can’t carry it and give it to other people,” Allen said.

“So, you were still taking the same precautions pre and post vaccine?” DeAngelis asked.

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“Yeah, there was never a question in my mind,” Allen replied.

Allen is among scattered reports of “breakthrough” cases – fully vaccinated people who are still getting infected.

That isn’t unique to COVID vaccines.

“No vaccine is 100% efficacious or effective,” said Dr. Anthony Fauci.

According to Dr. Fauci, it can happen if:

  • the vaccine itself is ineffective or was stored improperly.
  • a person has a poor immune response.
  • there’s a new strain circulating.

“There were essentially no deaths or hospitalizations in the individuals who are vaccinated,” Dr. Fauci said.

The head of the CDC said if you get a vaccine, it could still take two to six weeks to be fully protected.

Allen believes her shot likely made the difference in the severity of her illness.

“I would like to imagine that it definitely played a part,” she said. “So I am pro-vaccine. Go take care of yourself and take care of people around you.”

While dealing with COVID, Allen was in the process of launching a new business based on her passion for plants, which she discovered while temporarily furloughed from her real job.

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She’s now out of quarantine and back to work on both.