When you’re sick, all you care about is feeling less miserable—but once the temps drop during fall and winter, it can be tricky to figure out if you’re dealing with the flu, COVID-19, or a common cold. So many of the symptoms overlap, but there are a few key differences to keep in mind. (More on that later.) Of course, in order to stop your sniffles, you need to know what’s causing them in the first place. Here, doctors explain how to figure out the answer to your pressing cold vs. flu vs. COVID-19 questions so you can seek the treatment that will actually make you feel better.Cold vs. flu vs. COVID-19 symptomsPart of the reason it can be tricky to know whether you have the flu or a cold or even COVID-19 is simply that there are only a few minor differences between their symptoms.Cold symptomsIn general, cold symptoms show up primarily above your neck: Runny nose Coughing and sneezing Sore throat Slightly swollen glands Minor aches and painsFlu symptomsThis includes symptoms above and below your neck. You have all the signs of a cold, plus the following: Fever over 100°F Chest coughs Weakness and fatigue Headaches Chills Vomiting Diarrhea Full-body achesAnd, again, because COVID-19 should be considered, too, here are the biggest signs of that illness, per the Centers for Disease Control and Prevention (CDC).Fever or chills Cough Shortness of breath or difficulty breathing Fatigue Muscle or body aches Headache New loss of taste or smell Sore throat Congestion or runny nose Nausea or vomiting DiarrheaHow do I know if I have the flu or a cold?The biggest differences between the symptoms of influenza and a cold are their severity and how quickly they develop. With the flu, “one day you are feeling OK, and the next, all your symptoms arise,” says Michael P. Angarone, D.O., professor of infectious diseases at Northwestern Memorial Hospital.Compared to the flu, a cold is milder and symptoms gradually set in. “The flu is like a cold on steroids,” says Joseph Ladapo, M.D., Ph.D., professor of medicine at the University of California, Los Angeles. “I’ve heard patients say, ‘This is worst I’ve ever felt in my life.’” He also adds this: “If you don’t feel horrible, you probably don’t have flu.”But, like many illnesses, it’s tricky to say that this will happen in every situation. “You can be walking around with the flu—there are all different levels of severity,” says Timothy Murphy, M.D., senior associate dean for clinical and translational research at the University at Buffalo Jacobs School of Medicine. Infectious disease expert Amesh A. Adalja, M.D., a senior scholar at the Johns Hopkins Center for Health Security, agrees. “It’s impossible to really differentiate a cold from influenza because the symptoms overlap,” he says. “Influenza tends to be more severe and associated with fever and muscle aches, but it could be mild enough to be confused with the common cold.”It also matters if you’ve been vaccinated against the flu. While the flu vaccine won’t necessarily keep you from getting sick—vaccine effectiveness has ranged from 19% to 60% over the past decade, per CDC data—it “can give partial protection and can turn what would have been a more severe illness into a minor illness,” Dr. Murphy said.David Cennimo, M.D., assistant professor of medicine-pediatrics infectious disease at Rutgers New Jersey Medical School, agrees. “People who get vaccinated against influenza and have a ‘breakthrough’ infection tend to be much less sick with more mid symptoms that can be confused with a cold,” he says. “This confusion means that we really do need testing to be sure.”Basically, it can be confusing, even when you know all the classic signs of each illness. Still not sure what’s happening with your health? Asking yourself these questions can help:How severe does this feel?Cold: You feel mildly icky, and things get worse slowly. The first signs might include slight aches, a scratchy throat, a headache, and/or a low-grade fever.Flu: The flu usually hits you like a speeding train. You may first feel feverish at work, and by the time you get home you can barely muster enough energy to climb your porch steps. Every inch of you aches.Can I get out of bed?Cold: Yes, you can walk around. Though you might not want to commute to work or schlep the kids around, you can manage.Flu: In many cases, you’re flat on your back. Extreme fatigue may incapacitate you for at least a few days.What to do if you develop symptomsIn the past, doctors would usually recommend that you see your doctor if you have cold- or flu-like symptoms that make you feel lousy. But with COVID-19 now in the mix, that advice has changed a little. “Do not to go right to your healthcare provider,” says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine.“Any respiratory symptoms…should prompt COVID testing,” Dr. Adalja says. If that’s negative and you think there’s even a chance you could have the flu, Dr. Adalja recommends calling your doctor about getting tested for the flu. “There should be a low threshold for influenza testing because there are influenza antivirals that people can benefit from—if given early enough—especially the high risk,” he says.
When you’re sick, all you care about is feeling less miserable—but once the temps drop during fall and winter, it can be tricky to figure out if you’re dealing with the flu, COVID-19, or a common cold.
So many of the symptoms overlap, but there are a few key differences to keep in mind. (More on that later.) Of course, in order to stop your sniffles, you need to know what’s causing them in the first place. Here, doctors explain how to figure out the answer to your pressing cold vs. flu vs. COVID-19 questions so you can seek the treatment that will actually make you feel better.
Cold vs. flu vs. COVID-19 symptoms
Part of the reason it can be tricky to know whether you have the flu or a cold or even COVID-19 is simply that there are only a few minor differences between their symptoms.
Cold symptoms
In general, cold symptoms show up primarily above your neck:
- Runny nose
- Coughing and sneezing
- Sore throat
- Slightly swollen glands
- Minor aches and pains
Flu symptoms
This includes symptoms above and below your neck. You have all the signs of a cold, plus the following:
- Fever over 100°F
- Chest coughs
- Weakness and fatigue
- Headaches
- Chills
- Vomiting
- Diarrhea
- Full-body aches
And, again, because COVID-19 should be considered, too, here are the biggest signs of that illness, per the Centers for Disease Control and Prevention (CDC).
- Fever or chills
- Cough
- Shortness of breath or difficulty breathing
- Fatigue
- Muscle or body aches
- Headache
- New loss of taste or smell
- Sore throat
- Congestion or runny nose
- Nausea or vomiting
- Diarrhea
How do I know if I have the flu or a cold?
The biggest differences between the symptoms of influenza and a cold are their severity and how quickly they develop. With the flu, “one day you are feeling OK, and the next, all your symptoms arise,” says Michael P. Angarone, D.O., professor of infectious diseases at Northwestern Memorial Hospital.
Compared to the flu, a cold is milder and symptoms gradually set in.
“The flu is like a cold on steroids,” says Joseph Ladapo, M.D., Ph.D., professor of medicine at the University of California, Los Angeles. “I’ve heard patients say, ‘This is worst I’ve ever felt in my life.’”
He also adds this: “If you don’t feel horrible, you probably don’t have flu.”
But, like many illnesses, it’s tricky to say that this will happen in every situation. “You can be walking around with the flu—there are all different levels of severity,” says Timothy Murphy, M.D., senior associate dean for clinical and translational research at the University at Buffalo Jacobs School of Medicine.
Infectious disease expert Amesh A. Adalja, M.D., a senior scholar at the Johns Hopkins Center for Health Security, agrees. “It’s impossible to really differentiate a cold from influenza because the symptoms overlap,” he says. “Influenza tends to be more severe and associated with fever and muscle aches, but it could be mild enough to be confused with the common cold.”
It also matters if you’ve been vaccinated against the flu. While the flu vaccine won’t necessarily keep you from getting sick—vaccine effectiveness has ranged from 19% to 60% over the past decade, per CDC data—it “can give partial protection and can turn what would have been a more severe illness into a minor illness,” Dr. Murphy said.
David Cennimo, M.D., assistant professor of medicine-pediatrics infectious disease at Rutgers New Jersey Medical School, agrees. “People who get vaccinated against influenza and have a ‘breakthrough’ infection tend to be much less sick with more mid symptoms that can be confused with a cold,” he says. “This confusion means that we really do need testing to be sure.”
Basically, it can be confusing, even when you know all the classic signs of each illness. Still not sure what’s happening with your health? Asking yourself these questions can help:
How severe does this feel?
Cold: You feel mildly icky, and things get worse slowly. The first signs might include slight aches, a scratchy throat, a headache, and/or a low-grade fever.
Flu: The flu usually hits you like a speeding train. You may first feel feverish at work, and by the time you get home you can barely muster enough energy to climb your porch steps. Every inch of you aches.
Can I get out of bed?
Cold: Yes, you can walk around. Though you might not want to commute to work or schlep the kids around, you can manage.
Flu: In many cases, you’re flat on your back. Extreme fatigue may incapacitate you for at least a few days.
What to do if you develop symptoms
In the past, doctors would usually recommend that you see your doctor if you have cold- or flu-like symptoms that make you feel lousy. But with COVID-19 now in the mix, that advice has changed a little. “Do not to go right to your healthcare provider,” says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine.
“Any respiratory symptoms…should prompt COVID testing,” Dr. Adalja says. If that’s negative and you think there’s even a chance you could have the flu, Dr. Adalja recommends calling your doctor about getting tested for the flu. “There should be a low threshold for influenza testing because there are influenza antivirals that people can benefit from—if given early enough—especially the high risk,” he says.
