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This Is What a Breakthrough COVID Infection Feels Like

Despite being vaccinated, they got COVID-19. Here's what their symptoms were like and what experts say you should know

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Melissa Morelli, a teacher who works with special-needs children, woke up on July 19 with a stuffy nose, a headache and a bit of a cough. “I didn't think anything of it, because mild colds always make the rounds [in school],” says Morelli, who had the Pfizer vaccine in January and February. “I took some Tylenol and went about my week. ... COVID never crossed my mind."

It wasn't until six days later, when she landed in the ER for an unrelated problem — she had skimped on water despite the hot weather, got dehydrated and fainted — that she learned she had COVID-19. “In hindsight, I wish I had thought about it more and went to get tested after I had some cold symptoms,” she says.

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As the contagious delta variant continues to circulate, more vaccinated Americans are developing so-called breakthrough infections — defined as those that occur two weeks or more after completion of their vaccine regimen, be it a one- or two-dose version. No one knows exactly how often this is happening, because many breakthrough cases are completely asymptomatic and because the Centers for Disease Control and Prevention (CDC) has stopped tracking them unless they lead to hospitalization or death.

Based on the currently available evidence, such breakthroughs are believed to be fairly rare and mostly mild, says Perry N. Halkitis, dean of the Rutgers School of Public Health. The overwhelming majority of those who develop symptoms end up with minor coldlike ones similar to what Morelli experienced, though of course there are exceptions.

Jennifer Leascher had her second Moderna shot in February, and in early July, she tested positive for COVID. Unlike Morelli, however, Leascher's condition quickly worsened, and she was hospitalized with COVID pneumonia for four days. No one can explain to her why she got so sick.

"I'm 58 and have been an avid runner since 1997,” says Leascher, who is now recovering at home. “I do have hypothyroidism and asthma, but both were well managed."

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Symptoms to watch for

Generally speaking, vaccinated people who contract COVID-19 and develop symptoms are prone to the same ones that an unvaccinated person might experience. These include fever, cough, shortness of breath, fatigue, body aches, headache, sore throat, congestion, nausea, vomiting and diarrhea. Loss of taste or smell can sometimes serve as telltale clue, though it doesn't happen to everyone.

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"What is likely different is the severity of symptoms,” says Halkitis. “So while a very bad headache, a very bad sore throat or very bad gastrointestinal issues might be evidenced in the person who is unvaccinated, those same symptoms would be less intense in a person who is vaccinated.”

Indeed, the overwhelming majority of serious cases around the country are occurring in unvaccinated people. In fact, less than 1 percent of fully vaccinated individuals have been hospitalized with, or have died from, COVID-19, according to the latest data tracked by the CDC. Older adults, however, make up about 75 percent of the small percentage of serious cases.

Of course, there's a lot of room between remaining completely asymptomatic and being ill enough to require hospitalization. In the middle are people like Kelley Burnham Brown, 52, who was so eager to get vaccinated that she volunteered to participate in a clinical trial. She was fully vaccinated with the Novavax vaccine in May and tested positive on July 18.

"It's been like a sinus infection,” she says. “No fever or body aches; just sinus pressure and a constant headache.” (Although Novavax hasn't yet applied for an emergency use authorization that would enable its vaccine to be given to the general public, research has shown that it's more than 90 percent effective at preventing symptomatic COVID-19 and 100 percent effective at blocking moderate or severe disease.)

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Others, however, haven't fared as well. Elizabeth Meinz, 52, got the Johnson & Johnson vaccine in March and contracted COVID-19 in June. “I had all the symptoms: splitting headache, fever, cough and difficulty breathing,” she says. “I was so exhausted that I couldn't even walk the dog.”

Is it a cold? Allergies? COVID-19?

If you have any coldlike symptoms that might signal COVID-19, the CDC recommends you get tested — even if you've been vaccinated. (It also now recommends you get tested if you are vaccinated but have had known exposure to someone with suspected or confirmed COVID-19.)

While the official list of COVID-19 symptoms is quite long, the Zoe COVID Symptom Study — an app-based study that's been collecting data from millions of global contributors — recently released a list of the top five symptoms users have experienced and organized them based on vaccination status.

According to their findings, headache was the most common symptom, for both vaccinated and unvaccinated people. Sore throat also made the top-five list across the board, as did runny nose. But fever got a top spot only among those who were unvaccinated. Sneezing made the list only for those who were fully or partially vaccinated.

Why sneezing more than usual might be a symptom of a breakthrough case isn't clear, and it's certainly not the only red flag you should look for, doctors say. “I have not heard that sneezing is common with breakthrough cases, but overall I would say that the vast majority of breakthrough infections, if symptomatic, are much milder in vaccinated persons,” says Kristin Mondy, M.D., associate professor and chief of the infectious diseases division at the Dell Medical School at the University of Texas at Austin.

While the idea that you could still contract COVID-19 post-vaccination might be unnerving, keep in mind that the vaccines never promised 100 percent protection. Still, they come awfully close.

"The vaccine is safe and overall incredibly effective — at least 88 percent against the newest delta variant, [and] the risk of serious disease is very, very low for an average individual who has received a COVID-19 vaccine compared to those who are unvaccinated,” says Mondy. “I can't stress enough that if everyone does their part and gets vaccinated, then we can achieve herd immunity and prevent the spread of new variants [as well as protect] vulnerable populations.”

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