It starts with a sniffle, then it moves to a cough. Maybe you get a sore throat or achy muscles, or spike a fever. Is it a cold? Perhaps the flu? Could it be COVID?
It’s been three years since COVID-19 burst on the scene, adding yet another virus-causing illness that could be to blame for your feeling crummy. After all, the common cold, the flu and COVID-19 share a similar list of symptoms. Further complicating the guessing game are the COVID-19 vaccines and boosters, which can fight off some of the disease’s most severe symptoms, making it even more difficult to identify the culprit behind a mild cough or scratchy throat.
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As we face winter, when people head inside and respiratory viruses come out in full force, experts share some tips on how to distinguish among the different diseases and how to recover from each of them. Plus, they have some advice on what you can do to avoid getting sick in the first place.
COVID-19 has a few distinguishing symptoms
The truth of the matter is, several symptoms for cold, flu and COVID-19 overlap. Chief among them are sore throat, runny nose, cough, headache and body aches.
There are some more specific symptoms, though, that could signal your sickness is caused by COVID-19. Loss of taste and smell, for example, is a common warning sign of a coronavirus infection.
“Especially if you don’t really have a runny or stuffy nose and you have this symptom, that probably is something that’s more specific for COVID,” says Albert Shaw, M.D., an infectious disease expert and professor of medicine at Yale School of Medicine. “And it’s one we would see less so in someone with a common cold or someone with influenza.”
Could it be RSV?
Another virus that commonly causes cold-like symptoms is respiratory syncytial virus, or RSV. As with COVID and the flu, most people who get RSV (a lab-based test can detect an infection) recover in a week or two, but older adults are more susceptible to severe illness. Seasonal patterns for RSV in the U.S. used to be very consistent (mostly fall and winter), but the CDC says that is no longer the case. RSV is circulating in the spring and summer as well.
Symptoms in adults may include runny nose, sore throat, cough, headache, fatigue and fever; more severe cases can lead to pneumonia. There aren’t any treatments for RSV, but oxygen support may help adults who experience trouble breathing. There also isn’t a vaccine for RSV yet, but scientists are working to develop one.
Another symptom that’s more typical with COVID-19 than with the flu or a cold is diarrhea, Shaw says. It may not be as prevalent as some of the other COVID symptoms, but people still get it with a coronavirus infection. Diarrhea is not a common sign of flu in adults (it is in kids, though), nor does it usually accompany a cold.
“That said, there are other viral and bacterial illnesses that can give you diarrhea, so that alone doesn’t mean it can only be COVID. But if you’re trying to differentiate, I would say that those elements, if they’re present, might be helpful,” Shaw says.
Finally, disorientation could point to COVID-19, especially in older adults, says Kenneth Koncilja, M.D., a geriatrician at Cleveland Clinic.
“Older adults often present atypically. And with these recent BA.4 and BA.5 [variants], I’ve seen more of my older adults present with symptoms of confusion [and test positive for COVID-19], where you might think it’s a urinary tract infection,” he says.
So, if you or a friend or family member is experiencing a sudden onset of confusion, don’t rule out COVID-19, even if there’s no fever (older adults often don’t run fevers the same way younger people do, both Shaw and Koncilja note) or any of the other usual symptoms, like cough or fatigue.
“It’s a little disconcerting, because so many things can cause confusion,” Koncilja adds. “That’s why it’s important to talk to your primary care doctor or provider” if you experience it.
Sneezing a lot? That’s typically a symptom that’s more common with a cold than with flu or COVID-19, the National Institutes of Health says. And chances are if you have a cold, you won’t experience the body aches and fever that accompany the other two infections.
Keep a COVID test — or two — on hand
A crucial tool this time of year is an at-home COVID-19 test. That way, if you start to feel sick, you can check to see if your symptoms are due to COVID-19 in a matter of minutes.
Most private insurance companies cover the cost of these over-the-counter tests, and Medicare beneficiaries can receive up to eight a month, free of charge. You can also order four free tests from the federal government (visit covidtest.gov) or check in with a nearby health center to see if it offers COVID-19 test kits to members of the community.
“Particularly given the nonspecific nature of a lot of COVID symptoms and the fact that there can be a diminished fever response and other kinds of atypical symptoms, I think the safest thing would be to definitely test,” Shaw says.
If you’re positive for COVID-19, you may be eligible for an antiviral treatment that can significantly lessen your chances of severe illness. Two have been authorized by the Food and Drug Administration: Paxlovid, from Pfizer, and molnupiravir, from Merck and Ridgeback.
It’s important to start these medicines early in the disease course, though, so talk to your doctor right away if you find out you have COVID-19. Some pharmacists can also prescribe the pills, or you can find them at one-stop test-to-treat centers.
If you test negative for COVID but symptoms persist, your health care provider may conduct a flu test. As with COVID-19, prescription antiviral treatments taken early on can help you feel better if you have flu. Keep in mind, it's also possible to have both COVID and the flu (or another respiratory illness) at the same time. This is called a co-infection. And recent research suggests that people who have co-infections experience more severe symptoms.
If it’s a cold, there is no miracle cure. But the Centers for Disease Control and Prevention (CDC) says lots of rest and plenty of fluids can help you recover, and over-the-counter medicines may help ease symptoms you’re experiencing.
Stay up to date on your vaccines
One way to lower your likelihood of getting the flu or COVID-19 — or both at the same time — is to get vaccinated against each disease. Not everyone who gets vaccinated will be able to completely avoid an infection, but the separate shots can blunt the severity of symptoms and help to keep you out of the hospital.
When it comes to COVID-19, health experts recommend that fully vaccinated adults and kids roll up their sleeves for one of the new bivalent boosters. There are two options, one from Moderna and one from Pfizer-BioNTech.
For flu, adults 65 and older should ask for a high-dose vaccine this year, new CDC recommendations say. There are three options to choose from, but experts say the differences among them are minimal, so for most people, the best one to get is the one your doctor or pharmacist has available. There’s no need to space out your flu and COVID-19 shots, so if it’s more convenient to get them at the same visit, the CDC says that can be done.
And while there is no vaccine to help prevent a cold, there are several things you can do to avoid one: Wash your hands often; stay away from people who are sick; and disinfect frequently touched surfaces. These measures can also help you avoid the flu and COVID-19.
Identifying Cold vs. Flu vs. COVID
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Editor's note: This story, originally published Sept. 27, 2022, has been updated to reflect new information.
Rachel Nania writes about health care and health policy for AARP. Previously she was a reporter and editor for WTOP Radio in Washington, D.C. A recipient of a Gracie Award and a regional Edward R. Murrow Award, she also participated in a dementia fellowship with the National Press Foundation.