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'This is no cause for panic' | Small number of people get COVID-19 after getting fully vaccinated

In St. Louis County, 235,738 people are fully vaccinated. Out of that, only 71 of them contracted the virus after the fact. That breaks down to .03%

ST. LOUIS COUNTY, Mo. — They're called breakthrough COVID-19 cases.

This is when people are fully vaccinated but still contract the virus.

It was shocking news for Molly Macek, a 28-year-old healthcare worker who was one of the first to be vaccinated.

She got her second shot in January. 

But this past week, she felt under the weather. 

"I ended up being positive, which was a shock, because I am vaccinated and have been taking this seriously. I was in a bit of denial, I got tested three times," Macek said. 

Each test came back positive. 

The first few days, she had a stuffy nose, was fatigued and had chest pain. On day five, she is almost back to normal. 

She is among the small group of cases where this happens.

In St. Louis County, as of Wednesday, 235,738 people are fully vaccinated. Out of that, only 71 of them contracted the virus after the fact.

That breaks down to .03%.

"That is how low the number of breakthrough cases are," said Dr. Faisal Khan, Director of St. Louis County Department of Public Health. "This is no cause for panic or alarm. The breakthrough cases are not a reflection on the safety or the efficacy of the vaccines. The vaccine is very effective, it is working, it is doing exactly what is designed to do."

As for St. Louis city and St. Charles County, both health departments said they have not received a report or heard of any breakthroughs in their area, so far. 

A spokesperson for the Jefferson County Health Department says out of the 37,874 vaccinated residents in Jefferson County, four had breakthrough infections. That is .01%.

No vaccine is 100% effective.

There is a chance one could get it and the chances are low. So low, that nationwide of the 77 million people vaccinated, the CDC has identified just 5,814 breakthrough cases.

That's just .008%.

The CDC also said most of those breakthrough cases are mild.

RELATED: 30% of COVID 'breakthrough' patients show no symptoms, CDC says


In St. Louis County, there is a trend among these breakthrough cases.

Age is a common factor.

Dr. Khan said it's been seen among people 60 and older.

Most had mild symptoms, two were hospitalized, and all have recovered.

The health department said 44% of its cases are healthcare workers and 39% were asymptomatic.

"That depends on the frequency and intensity of repeated exposure," Dr. Khan said, "so healthcare workers are at particular risk."

Nationwide, according to the CDC, 45% of the reported infections were among people 60 years and older.

Of the breakthrough cases, 65% were women and 29% were reported as asymptomatic.

Seven percent were known to be hospitalized and 74 people, or 1%, died. 

Of the 396 hospitalized patients, 133 (34%) were reported as asymptomatic or hospitalized for a reason not related to COVID-19.

Of the 74 fatal cases, 9 (12%) were reported as asymptomatic or the patient died due to a cause not related to COVID-19.


Dr. Rachel Presti, Infectious Disease Physician at WashU just started up a study on why this happens.

Right now, the study is working with very few people, 10 to 15 St. Louisans. 

"Almost everyone we’ve seen have found out because they were exposed by a close exposure by a spouse and had minimal symptoms," Dr. Presti said.

Dr. Presti is looking to see if the virus is different from what's in the vaccine and looking at the immune response. 

She is trying to see if those antibodies match the virus they were infected with.

Results are still brewing, but her confidence in the vaccine remains high.

"The 95% efficacy isn’t 100% efficacy and so people do get infected. What we’re hearing so far is really reassuring that the vaccines do work," she says. "We still recommend highly people get vaccinated."


Even though you are vaccinated, Dr. Khan said to be aware of your contacts with other people who are not vaccinated yet.

Take precautions, such as mask-wearing and social distancing. 

He encourages everyone to get the shot.

"We are not going to get beyond this crisis unless we have overwhelming people vaccinated," Dr. Khan said.

Credit: Molly Macek

As for Macek, one of the people who falls under this unique group, she still believes the vaccine prevented her from getting severely sick since she has asthma. 

"I totally think it could’ve been worse if I didn’t get vaccinated," she said.

Advising others to take a shot at getting immunity.

"The benefits outweigh the risk completely, if I could go back and get the vaccine, I would do it again," Macek said.

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