Flu vs. the Common Cold

Your nose is running, you’re feverish and you’re wondering: Do I just have a cold or the flu? With respiratory illnesses sharing several symptoms, that’s a common question this time of year. But other symptoms offer clues as to whether it’s a cold or the flu, which vary in treatment, vaccine availability, complications, and seriousness.

Flu or Common Cold Symptoms

Symptoms can overlap or differ in degree:

  • Cough (appears in the flu and a cold).
  • Sore throat (appears in the flu or a cold).
  • Fever/chills (typically just appears in the flu).
  • Muscle and body aches (the flu).
  • Headaches (the flu).
  • Runny/stuffy nose (appears in both a cold or the flu).
  • Fatigue (the flu).
  • Vomiting and diarrhea (the flu, particularly in children).

Of course, another viral respiratory condition – COVID-19 – is now ramping up the confusion and urgency of determining exactly what it is you have. Respiratory syncytial virus, or RSV, a common virus that can infect the lungs and respiratory tract, also adds to the mix, particularly for vulnerable kids.

How to Spot the Differences

There’s always been some confusion between having a cold versus the flu, says. Sterling N. Ransone Jr., a family physician in Deltaville, Virginia, and president of the American Academy of Family Physicians. “These days, we have the coronavirus on top of that,” he says. “And we also see a lot of seasonal allergies in the fall and winter. So when somebody comes to my office with an acute respiratory condition, I have to think about going in order of severity: What am I worried about in the long term?”

Flu v. Cold Severity

“Influenza virus can be a little more severe than common cold viruses,” says Dr. Sara Bode, a primary care pediatrician and the medical director of Nationwide Children’s Hospital’s Care Connection School-Based Health and Mobile Clinics, based in Columbus, Ohio. Higher fever, body aches, and overall malaise – feeling unwell and very tired – are flu hallmarks, she says.


The abruptness of onset, how symptoms came on, is one clue. Flu has a more intense impact than the common cold and can lead to more serious health consequences.

When a patient says, “I was doing great yesterday – and then I felt like I was hit by a truck,” that’s almost always the flu, Ransone says. “When you have an acute-onset illness with muscle aches, you feel horrible and it comes on very rapidly, that’s usually the flu.”

A bad headache is another telltale flu symptom.

  • Flu: abrupt onset.
  • Common cold: gradual, milder onset.

Potential Complications

Runny nose and a cough can occur with the flu, but they’re more common with a cold, Ransone says. “It’s a gradual onset of symptoms and you usually don’t have a fever,” he adds. Now, if a patient tells him they’ve had a little bit of everything – a sore throat, runny nose, cough, and fever – that fever, in particular, makes him think: Could this be COVID-19? “You don’t see a fever as often with cold or seasonal allergies.”

  • Flu: pneumonia, bacterial infections, hospitalization, some deaths.
  • Common cold: usually no complications.

Kids, Colds and Flu

“Every year, a proportion of kids and adults can get severely ill from influenza and end up in the hospital,” Bode says. “So it’s certainly important to have a closer watch over your child and be monitoring them. You might want to go see their doctor if they look like they’re not really eating or drinking, or aren’t feeling themselves, just to get them evaluated.”

Parents should understand how serious flu in children can be, Bode says. “Every year we have a certain number of kids who have to be in the hospital or even very ill in the ICU with influenza – and that can be healthy children.”

With that in mind, “we definitely recommend the flu vaccine because that reduces the severity of the symptoms or prevents children from getting the flu altogether,” Bode says. With the flu vaccine approved for as young as six months of age, she says, “Even babies can get the flu shot. And that’s really helpful in preventing the spread.”

The common cold and the flu are similar in how people get infected. “They both spread through droplets primarily – so if you’re coughing on someone,” Bode says. “Viruses can also live on surfaces, so can spread as everyone’s touching the same things throughout the winter indoors.”

Viral Culprits

Beyond the common cold and the flu, COVID-19 and RSV are other viral infections to look out for. Different viruses cause respiratory illnesses:

  • Flu: Influenza A and B viruses. Every year, different flu virus strains predominate.
  • Common cold: Rhinoviruses (most common), parainfluenza virus, adenovirus, seasonal coronaviruses (not SARS-CoV-2).
  • COVID-19: SARS-CoV-2 virus.
  • RSV infection: Respiratory syncytial virus usually causes mild cold-like symptoms, but can be serious.


Early in the pandemic, loss of taste and smell became a hallmark COVID-19 symptom, says Ransone, who mentions that one of his first COVID-19 patients realized he couldn’t smell an alcohol wipe. “So that’s a big differentiator.”

While the loss of taste and smell may increase the likelihood of COVID-19, this does not mean you have COVID-19. The vast majority of COVID patients don’t lose taste and smell and, with newer variants, fewer people are losing these senses.

As with the flu, it’s important to know whether a patient is infected with COVID-19 rather than a cold, Ransone says. Because influenza and COVID-19 viruses can lead to severe complications and death, and with specific treatments available, “We really want to differentiate this so we can pick the most appropriate treatment for the patient to get better.”


Respiratory syncytial virus, or RSV, is another condition that can be confused with a cold, but like the flu, it can be more dangerous. Unfortunately, the current RSV season is bad. “It’s normally a disease we see in children between September and December-ish,” Ransone says. “We started seeing it in June of this year. This was a really weird RSV season in that a lot of our older children were getting it.”

In adults, RSV typically causes mild, cold-like symptoms that last about two weeks, Ransone says. For younger children and infants, particularly preemies, RSV can lead to hospitalization. “Unfortunately, it’s still going on,” he says.[ 

READ: Here’s What You Should Eat to Fight Off Colds and the Flu. ]


Testing can quickly reveal which type of respiratory virus is causing your symptoms. A simple test at your doctor’s office can confirm whether you have the flu. Rapid flu tests use a nasal or throat swab sample to provide an answer within 10 to 15 minutes. If your rapid flu test result is negative, you may not have the flu. However, false negatives are possible, and your health care provider may do follow-up testing to verify your diagnosis.

Your doctor may also test you for COVID-19. “When a patient comes in with fever and upper respiratory symptoms, I’ll do a COVID test,” Ransone says. “I’ll usually do a flu test based on whether they had the muscle aches and rapidity of symptoms coming on.”

Colds are diagnosed by signs and symptoms rather than a specific test.

Antiviral Drugs for Flu

With good flu treatments available, it’s important to diagnose it as soon as possible. Tamiflu (oseltamivir phosphate) is the most commonly prescribed antiviral drug for the flu. It’s taken as a pill or liquid suspension.

For the current flu season, three other prescription antiviral drugs are also approved by the Food and Drug Administration: Relenza (zanamivir) an inhaled drug; Rapivab (peramivir) an intravenous medication and Xofluza (baloxavir marboxil), a single-dose pill.

The use of these drugs depends on factors including the patient’s age, flu severity, medical conditions, and pregnancy or breastfeeding status.

Flu Vaccine

Doctors advise yearly flu vaccines, as does the Centers for Disease Control and Prevention. “CDC recommends the use of any licensed, age-appropriate vaccine during the 2021-2022 influenza season,” according to the agency website. About two weeks after vaccination, the body develops antibodies to provide protection from infection by circulating flu viruses.

In the U.S., quadrivalent flu vaccines protect against four flu viruses, including two influenza A and two influenza B viruses. These are major types of quadrivalent flu vaccines available in the U.S.:

  • Standard-dose flu vaccines are made with flu viruses grown in eggs (Afluria, Fluarix, FluLaval, and Fluzone).
  • The cell-based flu vaccine that’s made with a virus grown in cell culture and is egg-free (Flucelvax).
  • Recombinant flu vaccines are produced with technology that doesn’t use flu viruses or eggs. (Flublok).
  • The adjuvant flu vaccine contains an ingredient to create a stronger immune response in older adults. (Fluad).
  • The high-dose flu vaccine is also licensed for people 65 and older (Fluzone High-Dose.)
  • The nasal spray flu vaccine is a live attenuated vaccine containing a weakened virus (FluMist).

The type of flu vaccine appropriate for you or your child will depend on age, general health, and certain medical conditions. Talk with your doctor about flu vaccine options.

OTC Drugs

A variety of over-the-counter medications are available for flu or cold symptoms, but you may not necessarily need them.

OTC medicines can ease flu symptoms in kids. “For influenza, those body aches could definitely be helped by Motrin to help reduce those symptoms, so we recommend that,” Bode says.

It’s best to take OTC flu medications based on symptoms, Ransone says. “I generally prefer that people take medicines that match their symptoms, especially with a cold,” he says. “There are some multi-symptom medications out there. But why take medicine for something that you don’t have?”

Decongestant drugs help clear nasal congestion, Ransone says. “For a lot of dripping or rhinorrhea, when your nose is running (or you have) dripping down your throat, antihistamines will help with that,” he says. Cough suppressants or expectorants can ease a bad cough.

Bode advises limited use of OTC medications for children with colds. “For younger kids who have cold symptoms, usually we’re just recommending Tylenol or Motrin if they have a fever,” she says. “But otherwise it’s supportive care like lots of fluid at home, and rest. So, not really those over-the-counter medications.[ 

READ: Best Immunity Boosters. ]


The COVID-19 pandemic provided a worldwide crash course in preventing the spread of infectious diseases. It also reinforced healthy habits that have always helped prevent respiratory viruses from spreading:

  • Hand-washing and hand sanitizing.
  • Wearing face masks.
  • Personal protective equipment for health care workers.
  • Social distancing.
  • Staying home from work and school while contagious.

“Most of us are steeped in the preventive measures with COVID,” Ransone notes. “They work quite well to prevent both the flu and the common cold. Last year was probably one of the best years I’ve ever seen as far as the number of cold cases and influenza cases that came through my office.” Masking, social distancing, and hand-washing “are all incredibly important public health measures,” he says. “They help prevent the transmission of all three of these viral illnesses.”

These prevention methods are tried and true, Bode agrees. “In times when we’re not in a pandemic, we’ve always talked about this with the flu season coming: Really good hand-washing for kids is the No. 1 way you can reduce the chance of them getting the flu,” she says.

High-touch areas and kids at close quarters can promote the spread of germs. “When you’re at school, and you’re all grabbing the same doors and going through these congested areas, even (giving) your child hand sanitizer that they’re using throughout the day can really be helpful,” Bode says. “I feel like a lot of kids through this time of COVID really understand that now and have gotten good habits, so it’s keeping those up.

Seek Medical Advice

Don’t hesitate to ask your doctor about these symptoms, Ransone emphasizes. “A lot of family physicians now have capabilities of reaching their patients electronically,” he says. “So, if you’ve got a question, if you’ve got a respiratory syndrome, call your family physician and ask, and see whether or not they think you need to come in and be evaluated.”

Flu Emergency Warning Signs

Go to the hospital for symptoms like these, which can indicate serious flu complications:

  • Breathing changes: Fast or labored breathing, shortness of breath.
  • Blueness (cyanosis): Bluish lips or face.
  • Respiratory pain: Persistent chest or abdominal pain or pressure.
  • Severe muscle pain: A child could be refusing to walk.
  • Dehydration: Not urinating; no tears with crying children.
  • Fever: Above 104 degrees for children; recurring fever for adults.
  • Confusion: A patient seems disoriented or shows mental changes.
  • Chronic medical conditions worsen: For instance, asthma symptoms increase.

Fortunately, most people recover completely from common colds or the flu. Even so, they can make you feel both miserable and uneasy.

“Everyone had heightened anxiety this year as a parent,” Bode says. “I have three kids myself. We don’t want our kids to have to be home from school on quarantine. We’re all concerned about illness, maybe even more so than we were before.”

Illnesses can happen despite all your best efforts, Bode says. “The average child gets, typically, four to six respiratory viruses a year, meaning those mild colds.” With higher anxiety levels these days, “Having those visits with your pediatrician to just get reassured and talk through it and make sure nothing else is going on is not a bad idea,” she adds. “Just know that although COVID is out there, all these other viruses are out there too. Not everything’s going to be as severe.”

Back to School

Remote work and virtual learning reduced opportunities for any respiratory virus to spread. With school systems reopening, it’s more important than ever to keep sick kids home.

“Because the flu is the more serious illness, it’s often accompanied by fevers,” Bode notes. “Schools have those recommendations that you don’t come back until you’re fever free for at least 24 hours. When you do have a fever, that’s when you have the highest chance of infecting others, and you don’t feel well. Typically, kids with the flu are often out a few more days than just a cold.”

Returning to school may be more complicated as the pandemic intersects with the normal cold and flu season. “Right now, in the winter, both of these can overlap with symptoms of COVID in kids, too,” Bode says. “Schools are often requiring a COVID test just to ensure that it’s not COVID. So we’re seeing a lot of kids already with common cold symptoms (for whom) we’re needing to do a COVID test to make sure that’s not what it is before they go back.”


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