Is It a Cold? The Flu? COVID? Or RSV?

Another symptom that’s more typical with COVID-19 than with the others 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 the flu in adults (it is in kids, though), nor does it usually accompany a cold or RSV.

“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 of help,” Shaw says.

Disorientation could point to COVID-19, especially in older adults, says Kenneth Koncilja, M.D., a geriatrician at the Cleveland Clinic. “I’ve seen more of my older patients present with symptoms of confusion [and test positive for COVID-19], where you might think it’s a urinary tract infection,” he says.

And wheezing is more often a symptom associated with RSV, Gravenstein says, though people with flu and COVID can wheeze too, he notes.

Sneezing a lot? That’s typically a symptom that’s more common with a cold or RSV than with the flu or COVID. And chances are, if you have a cold, you won’t experience the body aches and fever that accompany an influenza or coronavirus infection. (RSV can cause a low-grade fever, though.)

Keep a COVID test — or two — on hand

It’s still important to keep an at-home COVID test (or two) on hand — especially during fall and winter. 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. Don’t have any tests? The federal government reopened its program, and each U.S. household can order four free tests.

There are also at-home tests available at pharmacies and some major retailers that can check for flu and COVID at the same time, with one swab of the nose. 

If you’re positive for COVID-19, your doctor may prescribe an antiviral pill, like Paxlovid (nirmatrelvir/ritonavir) or Lagevrio (molnupiravir), which can significantly lessen your chances of severe illness. For flu, there are also antiviral medications that can treat an infection. In both instances, it’s important to start these treatments early in the disease course, so talk to your doctor right away if you find out you have COVID-19 or flu, or suspect you do and want to get tested by your provider. 

Prescription medications usually aren’t prescribed for RSV, although some bad cases may require hospitalization. That could change soon, however, since “there are a variety of treatments for RSV that are in clinical trials,” Gravenstein says.

For now, RSV care often calls for fluids, rest and symptom management with over-the-counter medications, according to the CDC. The same goes for a cold.

It’s not too late to get your vaccines

One way to lower your likelihood of getting the flu, COVID-19 and RSV in the first place is to get vaccinated against each disease. And the good news is: If you skipped these shots in the fall, it’s not too late to get them. “In general, we say that any time during the respiratory season is a good time to get a vaccine if you haven't gotten it,” Gravenstein says.

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.“The vaccines are a lot like seat belts,” Gravenstein explains. “Wearing a seat belt doesn't keep you from getting in a car accident; you just don't get hurt as badly.”

When it comes to COVID-19, health experts recommend that everyone 6 months and older get the recently updated coronavirus vaccine; adults 65 and older should plan on getting a second shot in the spring. Even with new coronavirus variants in the mix, health experts say the vaccines still help protect you from severe illness if you catch COVID.

For the flu, adults 65 and older should ask for a high-dose vaccine, CDC recommendations say. There are three options to choose from, but experts say the differences among them are minimal. 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.

There’s also an RSV vaccine available, and it’s recommended for all adults 75 and older and for those ages 60 to 74 with certain risk factors, such as heart disease, lung disease and diabetes.

While there is no vaccine to help prevent a cold, there are several steps 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 many other illnesses swirling about this cold-weather season.

Editor’s note: This story, first published Sept. 27, 2022, has been updated to include new information.