You're vaccinated. You've got the sniffles. Is it a cold, allergies or a breakthrough case?

As flu season approaches, many are having trouble differentiating between symptoms. Here's what experts say

By Nicole Karlis

Senior Writer

Published September 16, 2021 3:02PM (EDT)

Allergic man blowing on wipe in a park on spring season a sunny day (Getty Images/Pheelings Media)
Allergic man blowing on wipe in a park on spring season a sunny day (Getty Images/Pheelings Media)

It started with the sniffles.

Ominously, I hadn't had a runny nose since before the pandemic. I half-hoped that it was related to the wildfire smoke that had drifted to the San Francisco Bay Area from the Caldor and Dixie wildfires near Lake Tahoe. 

It got worse. The next morning I woke up stuffy, almost completely unable to breathe through my nose. And a sore throat accompanied. That's when the panic set in.

This went beyond wildfire smoke symptoms or seasonal allergies. As the day continued, my sore throat worsened. I had sneezing fits, a headache, mild cough, and just an overall feeling of being sick. Even though I'd been vaccinated, I feared I had somehow contracted a breakthrough case.

I started obsessively googling breakthrough Covid symptoms. Alarmingly, according to the Zoe Covid study, headache, runny nose, sneezing, sore throat, and loss of smell, are the top five symptoms fully vaccinated people report when infected. I was four for five. My husband started to feel stuffy too, so he joined me in making an appointment to get a COVID-19 test the next day.

Nearly 24 hours later, our results were in: we were negative. Evidently, it was just a cold.

I was grateful, in more ways than one. Because I work from home, I easily avoided exposing anyone to the virus (besides, unfortunately, my immediate family). But the experience did spur a thought: mid-pandemic, the symptoms of a normal cold can be something more ominous. 

In part, that's because the recommendations for quarantining due to even a mild case of COVID-19 — as most breakthrough cases are — are much more severe than for a normal cold. Those with symptoms like mine (which could have just as easily been COVID-19 are supposed to self-isolate until they've received their test results. If a fully vaccinated person tests positive, they have to self-isolate for at least 10 days. In other words, getting a cold post-pandemic is quite different from getting a cold in 2019.

The Centers for Disease Control and Prevention (CDC) states that, with the delta variant (which is the dominant strain in the U.S.), fully vaccinated people can still spread the virus to others — though, notably, they do appear to spread the virus for a shorter time. 

My experience is not unique: millions of vaccinated Americans have or will experience similar symptoms, and fear the worst. I was lucky to easily be able to find and schedule a COVID-19 test, though not everyone is so lucky. In this situation, how are the fully-vaccinated supposed to know if their common cold symptoms signify COVID-19, allergies or just a plain old cold? And what challenges will we face this winter, when cold season starts in earnest?

In an interview, Dr. Amesh Adalja said when it comes to deciphering between seasonal allergies, a cold and a COVID-19 infection despite vaccination, the easiest to rule out are seasonal allergies.

"People with allergies usually have some history of seasonal allergies, so it's not usually something that comes on out of the blue," Adalja said. "It's something that has triggers, based on certain pollen or certain times of the year, or certain exposures like cats or dogs or whatever it might be, so allergies usually have some history that helps to distinguish them from something that's not analogy that's an infection."

Adalja adeed that allergies will usually not include a fever, which is usually a good indicator that a person's body is fighting off an infection. Dr. Purvi Parikh, an immunologist with Allergy & Asthma Network, agreed.

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"Generally allergies have more itchy symptoms — they are on bilateral or on both sides rather than one sided and there is a seasonal component," Parikh said in an email. "Generally with cold flu or Covid, there's fatigue, muscle aches and fever (over 100.4°) and loss of taste and smell. Covid and flu can also have stomach issues like nausea, vomiting or diarrhea."

Doctors have reported seeing sneezing as a symptom in breakthrough cases, something that has been reported in the Zoe Covid study. Sneezing is a new symptom compared to the hallmark ones — cough, fever, fatigue, muscle aches— from the beginning of the pandemic. While there has been speculation that it is unique to the delta variant, that has yet to be scientifically confirmed. Yet researchers at the Zoe Covid study state: "If you've been vaccinated and start sneezing a lot without an explanation, you should get a COVID-19 test, especially if you are living or working around people who are at greater risk from the disease."

Of course, people with breakthrough cases often experience very mild symptoms. The COVID-19 vaccines remain effective in protecting people from getting seriously ill or being hospitalized from COVID-19. Still, infections despite vaccinations can happen. As doctors continue to say, no vaccine is 100% effective.

Adalja said the only way someone can know for sure if they are experiencing a cold or COVID-19 is through a test.

"I think that because there's a lot of public health importance to COVID-19 cases, even mild ones, that you can't just brush off upper respiratory symptoms and assume that it's inconsequential because you might be infected with COVID-19 and you might be able to spread it to somebody," Adalja said. "I think that those types of symptoms should trigger testing or thinking about, 'Do I have allergies?' — all those types of questions."

Adalja added that at-home testing is a good option for people in this situation. The BinaxNOW COVID-19 test is available at Walgreens, and provides results in 15 minutes, but it costs $23 for a kit of two tests. If these tests aren't available near where you live, or if you can't afford one, you will likely have to go find a nearby free testing site. This could be challenging for many during the winter, when colds and flus typically rise. 

"There are so many people who either don't have paid time off, or who can't take time off during the day, there are demands on them to be at work," said Shelby O'Connor, a Professor in the Department of Pathology and Laboratory Medicine at the University of Wisconsin–Madison.

"It's really difficult for them, and I'm not judging anyone — I just think it's difficult to make those types of decisions."

Dave O'Connor, who is also a professor in the Department of Pathology and Laboratory Medicine at the University of Wisconsin–Madison, believes the government should make at-home rapid tests free. O'Connor said this move could be "critically important," and be the barrier between families sending their child with a cough or runny nose to school or not.

"More of that kind of testing could be really helpful in determining whether to send your kid to school or not," Dave said. "But if it's 25 bucks to buy a set for two of those tests, that's going to be 25 bucks too much for a lot of families."

By Nicole Karlis

Nicole Karlis is a senior writer at Salon, specializing in health and science. Tweet her @nicolekarlis.

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