Can You Get COVID After Being Fully Vaccinated? Chicago's Top Doc Breaks it Down

Can you get coronavirus after being fully vaccinated?

The answer is yes, but what are the odds?

Chicago Department of Public Health Commissioner Dr. Allison Arwady sought to answer that question during a Facebook Live Thursday, noting that while infection post-vaccination is possible, it's also rare.

"If you have been vaccinated, you can get COVID," Arwady said. "It does not happen very often."

While the vaccine itself cannot give you the virus, it is also not 100% effective at preventing the virus entirely, though those who receive the vaccine are far less likely to be hospitalized or die from it, data shows.

"In the trials, it's about a one in 20 chance that if you get exposed to COVID you still could get COVID even if you were fully vaccinated," Arwady said. "The good news is that... we see all three of these vaccines amazingly protective against the severe outcomes of COVID, almost 100% protective against getting hospitalized or dying from COVID. But it is possible, it doesn't happen very often, but it is possible to get COVID and that is part of why we continue recommending while we still have a lot of COVID around that when you're in public spaces, etc., you wear that mask and if you are interacting with someone who has not yet been vaccinated and is at high risk you should absolutely keep wearing that mask."

In clinical trials, Moderna's vaccine reported 94.1% effectiveness at preventing COVID-19 in people who received both doses. The Pfizer-BioNTech vaccine was said to be 95% effective.

The FDA said Johnson and Johnson’s single-shot vaccine was 85% protective against the most severe COVID-19 illness, according to a study that spanned three continents. It also showed protection against COVID-19 related hospitalization and death, beginning 28 days after vaccination.

For a complete breakdown of the three vaccines, click here.

Arwady said the risk of contracting COVID after vaccination will decrease as more people get vaccinated, however.

"As our case numbers go down, as we really sort of get past COVID, the chance that you will be exposed to COVID will be even lower and this won't be as much of a concern, but we call it a breakthrough case when we have examples of people who are fully vaccinated," Arwady said.

In Chicago, Arwady said there have been few reported cases so far. Of the more than 1 million vaccinations in the city, there were an estimated 23 post-vaccination infections reported.

"Most of those people were actually asymptomatic," Arwady said. "They didn't have symptoms, we were testing them because they work in a hospital or they're at a long-term care facility."

The Illinois Department of Public Health told NBC 5 earlier this month it is also tracking cases of individuals who have been vaccinated and test positive for COVID-19. According to IDPH, of the more than 1.6 million people who are fully vaccinated, 217 reported a positive test more than two weeks after their last vaccine dose.

Ariel Silver of Northbrook, a sales manager for a medical device company, said she received her second dose of the Pfizer vaccine in mid-January and tested positive for COVID-19 in early March.

“Having been fully vaccinated for six weeks and then to get a positive COVID test, I was shocked,” Silver said.

Silver said her two young daughters tested positive in late February, and soon after she started feeling sick.

“It hit me hard," she said. "I’ve read that if someone vaccinated gets COVID, it’s usual very mild symptoms. But for two days my symptoms were not mild at all. I was in bed, very ill."

According to the Centers for Disease Control, the vaccine will help keep people from getting seriously ill, but those who are fully vaccinated should still take proper health precautions, particularly in public places, as "we’re still learning how vaccines will affect the spread of COVID-19."

“We shouldn’t be surprised about some people still getting infected, especially if they have high risk exposures, like a household exposure, but what we shouldn’t expect are severe infections because we know the vaccines were highly protective against from any hospitalizations,” said Dr. Jonathan Pinsky, a medical director and infectious disease control and prevention specialist at Edward Hospital.

Health experts have also expressed concern about new and emerging variants of the virus. Though studies have shown the current vaccines provide protection against known variants so far, they may not be as effective against the new strains.

The variant from South Africa, for example, reduced Pfizer-BioNTech's antibody protection by two-thirds, according to a February study. Moderna's neutralizing antibodies dropped six-fold with the South Africa variant, CNBC reported.

But boosters and new versions of vaccines that target the variants are already being explored.

Pfizer-BioNTech is testing a third booster shot of its vaccine on fully vaccinated people.  

"The flexibility of our proprietary mRNA vaccine platform allows us to technically develop booster vaccines within weeks, if needed," Ugur Sahin, CEO and co-founder of BioNTech, said in a release.

Moderna is also testing a potential third dose of its current vaccine, and a possible booster shot specifically targeting the South Africa variant.

Meanwhile, Johnson & Johnson CEO Alex Gorsky said during an interview with CNBC's "Squawk Box" earlier this month that the company is well-positioned to adapt its vaccine for variants, and is working on developing software that will "help address some of these new and emerging variants."

Still, Arwady stressed the importance of getting the vaccine.

"Nobody [who is vaccinated] has been hospitalized or died or gotten seriously ill, but it is a small piece of this and I don't want people to freak out about this," she said. "The vaccine continues to work just as it has looked and is expected to work. And again if everybody's vaccinated, not a big concern."