COVID, Flu Or RSV? Here’s How To Tell The Difference.

Three respiratory viruses are circling at a high rate right now — the flu, COVID-19 and RSV (or respiratory syncytial virus).

These viruses have similar symptoms in most healthy adults but can impact certain populations (children, older adults or immunocompromised people) more severely. Also, it can be helpful, in general, to know what virus you’re dealing with for your peace of mind.

Unfortunately, there isn’t a surefire way to tell these viruses apart (aside from testing, which isn’t always available). But some telltale signs can help you glean what you’re dealing with. Here, experts share signs to look for to determine which virus you have.

First, severe RSV is most common in children and immunocompromised adults.

According to Dr. Laolu Fayanju, regional medical director at Oak Street Health in Ohio, RSV generally infects children. And nearly all children get RSV by the age of 2.

So, if you’re dealing with sick infants and young toddlers, there’s a higher chance that their infection is RSV compared to other populations.

This child will usually present with a runny nose [and] fever,” he said.

While symptoms like a runny nose or low fever aren’t enough to bring your child to their pediatrician, another sign of RSV — trouble breathing — is a reason to go, added Dr. Vandana Madhavan, clinical director of Pediatric Infectious Disease at Mass General for Children.

“If you’re noticing your child is working harder to breathe … [or] if you’re noticing they’re not drinking as much, those are all signs the baby needs to come in,” Madhavan said.

If you don’t notice those symptoms, your child likely does not need to go to the doctor, and you can instead call to talk to your pediatrician about virus management.

Madhavan noted that doctor’s offices are overrun right now, and if you bring your child in for mild symptoms that would otherwise get better at home, there’s a chance they could pick up another illness while at the doctor.

Also, adults with certain chronic conditions are at risk of severe RSV, particularly “older people with chronic lung diseases,” Fayanju said.

Gastrointestinal issues are not generally associated with RSV.

If you have RSV, it’s unlikely that you will experience gastrointestinal issues, both Fayanju and Madhavan said. These side effects are typical of a COVID-19 infection, which can cause vomiting and diarrhea.

Influenza can also cause vomiting and diarrhea, Madhavan noted. But, keep in mind that this is much more common in children than adults, according to the Centers for Disease Control and Prevention (CDC). Most adults with the flu won’t have gastrointestinal issues.

Loss of taste and smell is most common during a COVID-19 infection.

A loss of taste and smell is one way to distinguish COVID-19 from the flu and RSV, Fayanju said, although that symptom is less common now than it was in the earlier days of the pandemic.

This isn’t the same as the loss of taste and smell from congestion. The loss of taste and smell with a COVID-19 infection generally happens pretty early on as one of the first signs of the virus ― sometimes even with no other symptoms, according to the Cleveland Clinic.

Madhavan said there is no guarantee that you’ll have this side effect even if you have COVID-19, but if you do, it’s likely a sign of the virus and not the flu or RSV.

Lasting symptoms are usually a sign of COVID-19.

“Unlike flu and RSV, COVID appears to have lingering long-term effects, ” commonly known as long COVID, Fayanju said.

This can include brain fog or confusion after the infection clears up or a loss of taste and smell that doesn’t return for weeks. But, similar to above, not all COVID infections will lead to long COVID (and a new study says by taking the antiviral Paxlovid, you can reduce your risk of developing the condition).

It’s less common for flu and RSV to result in long-term symptoms, but studies show that RSV can cause long-term wheezing after infection.

Additionally, Fayanju noted that flu can “lower the body’s natural defenses” and cause “an inflammation cascade that can set off other diseases, mainly heart attacks [and] strokes, especially in adults.” COVID-19 also results in higher levels of inflammation in the body post-infection that puts you at risk for stroke, heart attack and more.

This underscores the importance of getting your seasonal flu vaccine and COVID shots.

Carol Yepes via Getty Images

One way to tell what virus you have is by taking a COVID test — tests for RSV and flu are available, too, but COVID tests are the most readily available.

Keep in mind that you could also have two infections at once.

In news no one wants to hear, it’s also possible to catch two infections at the same time, according to Madhavan. Especially during times of high virus spread, like right now.

“You might not catch them both at the same time, but you might have cough and cold symptoms and then develop a fever, and it might not be the evolution of that original set of symptoms,” she said. “It might be that you have two infections going on.”

Last winter, the term “flurona” grew in popularity as omicron and flu cases surged throughout the country. Some people were infected with both viruses at the same time.

“It is true that when you’re infected, your immune system is under attack. Therefore your immune defenses are weakened. And therefore your ability to defend against another infection is reduced,” David Edwards, an aerosol scientist, faculty member at Harvard University, and inventor of FEND, a nasal mist that aims to trap and flush out tiny pathogens, previously told HuffPost.

So, as your body fights off one infection, it is also more susceptible to others.

Overall, it’s hard to tell the difference between these viruses based on singular symptoms.

I think the point to emphasize is that there is so much overlap in symptoms among the three,” Madhavan said. “They’re all primarily respiratory viruses.”

She noted that the flu and RSV could resemble an upper respiratory tract infection or a common cold in healthy adults. COVID can also present like this in people who are fully vaccinated against the virus.

And, just because you have a specific virus doesn’t mean you’ll have the same symptoms as someone else — your COVID infection could come with a bad cough, while your partner’s COVID infection may present as fever and fatigue.

You may be able to get tested to determine what virus you have — but it may not make a difference in your treatment.

Both Madhavan and Fayanju noted that COVID-19 at-home tests are easy to come by; you can buy them from your local pharmacy or order them online from retailers like Amazon.

If you test positive for COVID, your treatment options can change a bit; certain antiviral therapies can tame your infection. You should also alert anyone you came in contact with, Madhavan added.

The same goes for the flu — there are at-home flu tests available, and testing is also available at clinics. Positive tests can lead to certain antiviral flu treatments, according to the CDC.

However, remember that not all flu and COVID infections require antiviral treatments. Some cases stay pretty mild, and not all people are eligible for the antivirals.

There are also at-home RSV tests, but they tend to be pretty expensive, Fayanju said. You can get tested for RSV at the doctor, though it isn’t necessary in mild cases of the disease (and remember that doctor’s offices are overrun right now).

When it comes to RSV, a positive test isn’t typically going to change the treatment plan, Madhavan said. “For RSV, either at home or in the hospital, it’s really just supportive care — making sure someone is hydrated [and] maintaining a good oxygen level.”

Follow health precautions to lower your risk of getting sick.

“Continue to take all of these viruses very, very seriously,” Fayanju said. “We’re about to begin the holidays … and [people will be] traveling and gathering,” which means more chances for virus spread.

It’s important to think about lowering your risk — stay home if you’re sick, wash your hands, wear your mask in crowded spaces, and get vaccinated for COVID-19 and the seasonal flu, he said.

Through these measures, Fayanju added, we can “keep people well and out of the hospital through the holidays.”

Experts are still learning about COVID-19. The information in this story is what was known or available as of publication, but guidance can change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.