Does a Runny Nose Mean You Have COVID-19, the Flu, or a Common Cold?

You wake up one day, and your nose feels a little stuffy. You find yourself reaching for that box of Kleenex more and more, and to your dismay, the crumpled tissues are starting to pile up. Maybe there’s an ominous tickle in your throat that just won’t go away, no matter how much water you chug.

It’s upsetting but not surprising: ‘Tis the season of respiratory viruses.

As we anticipate the yearly uptick of flu and common cold cases, how can we distinguish those sicknesses from the still-prevalent and virulent COVID-19?

If there’s one thing COVID-19, the flu, and the common cold all have in common, it’s that they’re caused by viruses. The culprit behind COVID-19 is the novel coronavirus SARS-CoV-2, while the more familiar and well-studied influenza A and B viruses prompt our annual flu season. Common colds can spring from all sorts of viruses such as rhinoviruses.

This sickness trifecta also shares overlaps in symptoms, particularly in the case of COVID-19 and flu.

While cold viruses tend to attack your upper respiratory tract – meaning your nose, sinuses, and throat – COVID-19 and the flu can both infiltrate deeper into your lungs, according to Andrew Pekosz, a virologist at Johns Hopkins University.

“[COVID-19 and flu] infect different cell types, but at the end of the day, they generate the same type of immune response and the same type of damage to your respiratory tract, which is why those symptoms are so similar,” Pekosz says.

Read more: What Is A "Twindemic," And Why Should We Worry About It Going Into Flu Season?

So, what do you do if you have a runny nose? The common cold has a bit of a stronger distinction from COVID-19 or flu. That’s because when you come down with a cold, you rarely feel the kinds of fevers and aches you may experience with the latter two.

Pekosz explains that you feel a cold in your throat and nose the most, because that’s where cold viruses replicate best. However, just because you’re only experiencing a runny nose doesn’t mean you definitely have a cold.

“The only problem, of course, is those could be very early signs of COVID,” Pekosz says. “Those are standard symptoms for a common cold almost any day you’re infected; those are maybe the day one symptoms for COVID.”

Pekosz adds that most cases of COVID-19 and the flu are difficult to distinguish anyway. When we come down with the flu, the classic signs are a rough several days with fevers and newfound pains plaguing our bodies. But those symptoms are common with COVID-19, too – on top of coughing or feeling short of breath.

We used to see loss of smell and taste as a telltale sign of COVID-19, but Pekosz points out not everyone infected with the coronavirus loses those senses. It’s not a symptom worth hinging a firm positive or negative on.

“It’s really that fever and those systemic feelings of fatigue and tiredness that should differentiate between the common cold, and COVID or flu,” Pekosz says. “But there’s really nothing that consistently differentiates between COVID and the flu.”

The speed at which symptoms manifest according to respective incubation periods isn’t a reliable marker either, given it’s hard for the average person to know when they initially got exposed.

The only surefire way to know what’s afflicting you is to get tested. Free COVID-19 tests are still available in pharmacies, which help at least rule out one potential illness and inform the next course of treatment.

Read more: The Possibility Of "Flurona" And What Two Viruses Can Do At Once

Most people with COVID-19 experience mild illness, according to the Mayo Clinic, therefore they can recover at home. The prescribed treatment resembles the tried-and-true program for overcoming cold and flu symptoms: Get lots of rest, drink plenty of fluids, take medications.

Antivirals also help combat the flu and COVID-19. Pekosz adds that this is especially imperative for those in high-risk groups – which might include older adults or immunocompromised people.

“For high-risk populations, getting antivirals makes a big difference in terms of disease severity. But it’s important to note that you have to take those antivirals within 48 hours or so of showing symptoms,” he says. “So, pay attention to your symptoms, because the faster you get antivirals, the better off you’ll be.”

COVID-19 and the flu can lead to possible complications. Even mild COVID-19 symptoms could worsen unexpectedly. Pekosz says two warnings to pay attention to are difficulty breathing and energy level.

“If you really have to take deep breaths just to feel like you’re actually getting some oxygen into your system, that’s one sign,” he says.

Another red flag is if you’re in so much pain, or so weak, that you can’t get up and move around. Other emergency signs that warrant seeking medical attention, as listed by the Mayo Clinic, include persistent chest pain or pressure, new confusion, or skin discoloration.

Read more: Is Vitamin C Actually an Effective Cold Remedy?

A group of Canadian and Australian researchers compared the flu and COVID-19 data across four countries in 2021: Australia, Brazil, Canada, and the U.S. They found that in all these places, flu cases notably plummeted in the 2019 to 2020 season, coinciding with the introduction of government-mandated health measures to curb COVID-19 spread. In fact, there was virtually no flu season in the northern hemisphere.

Yet, the persistence of COVID-19 cases evidenced its virulence compared to the flu, according to the authors.

Likewise, to Pekosz, COVID-19 still stands apart from influenza in terms of true seasonality – it sticks around, rain or shine.

“Unless we see it go away, then it’s always going to be around,” he says, “and it’s always going to be a more significant risk to people than influenza.”

Read more: Why Are Viruses More Active In The Winter?

The measures some bemoaned, and others embraced in the pandemic still apply. Practices like social distancing, masking, and washing your hands prevent all sorts of potential illnesses, not just COVID-19.

Pekosz adds that good coughing and sneezing hygiene also curbs spread. On top of that, he emphasizes paying attention to your symptoms – especially the early ones.

Plus, stay up to date with vaccinations. The recent rollout of COVID-19 boosters continues to reduce your risk of contracting severe illness and complications, and are particularly important to keep up with in the face of new variants.

For example, new Omicron strains mainly evolve to avoid pre-existing immunity, Pekosz says. Like the yearly flu vaccination, one shot won’t protect you from all strains or variants forever.

Read more: What New Variants Of COVID-19 Are Currently Circulating?

“It’s always going to be a dog chasing its tail kind of thing,” Pekosz comments. “It always takes some time for us to make a vaccine against a particular variant, and while we’re making the vaccine, the virus is still out there changing.”

While vaccines don’t make you 100 percent immune from infection per se, they do protect you against serious disease.

There’s plenty of tools at hand to keep you safe and sound this holiday season. But if you do start coming down with something, you’ll hear the same thing, whether it’s from the CDC or your friends: Stay home. Not just for your own sake, but to protect others, too.

“Even if you’re COVID negative,” Pekosz says, “you still got something that can probably be spread to someone.”

Read More: Why We Feel So Terrible When We Get Sick

While these respiratory illnesses share some common symptoms, they have distinct characteristics. The flu and COVID-19, in particular, can lead to more severe health complications compared to a common cold. It's important to recognize the differences for proper treatment and prevention, especially in the context of the ongoing COVID-19 pandemic.

The flu and the common cold are contagious illnesses that affect your respiratory system, but they're caused by different types of viruses. The flu is only caused by influenza viruses, while the common cold can be caused by several different viruses, such as rhinoviruses, parainfluenza, and even some coronaviruses (not COVID-19) that are around during certain seasons.

COVID-19 and the common cold both originate from viral infections. The SARS-CoV-2 virus is responsible for COVID-19, while rhinoviruses are the most frequent cause of the common cold. These viruses share similar transmission methods and produce many overlapping symptoms, yet they exhibit some distinct differences.

COVID-19 and the flu are caused by different types of viruses. The one that causes COVID-19 is called SARS-CoV-2, which is a coronavirus. On the other hand, the flu is caused by different viruses, known as influenza A and B.

While there are some overlapping symptoms, including fever, cough, and body aches, certain signs like loss of smell or taste, and the severity and progression of symptoms, can help differentiate COVID-19 from the flu. However, due to similarities, testing remains crucial for accurate diagnosis.

Some of the symptoms your body is fighting a cold may include a runny or stuffy nose, sore throat, cough, mild fever, sneezing, watery eyes, and mild fatigue.

Yes, it's possible to have flu symptoms without a fever, though it's less common. Symptoms can include cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, and fatigue.

You could feel sick from hypothermia or frostbite but the common cold is caused by viruses, not cold weather. However, cold weather can contribute to conditions that facilitate the spread of viruses.

Read More: Will COVID-19 Need an Annual Vaccine Like the Flu?