Doctors break down what makes each respiratory illness similar and different.

The cold-weather season has arrived, and with the drop in temperature often comes a boost in respiratory illnesses each year—and as COVID-19 continues to spread, it's important to monitor your health for this infectious disease, along with the common cold and flu.

picking up a tissue
Credit: Getty / Mumemories

Since the common cold, the flu, and COVID-19 are all forms of respiratory illnesses, understanding their differentiating symptoms can be tricky, says Evelyn Darius, MD, a physician with PlushCare, a leading provider of virtual primary care. "Some of the early symptoms of a respiratory illness are similar, regardless of the virus causing it," she says. "As a result, it's difficult to tell the difference, especially in the early phase."

We asked three doctors which symptoms are unique to the common cold, the flu, and COVID-19 to help you better understand and identify each illness.

Common Cold Symptoms

The symptoms of a common cold usually peak within two to three days, according to Dr. Darius. These symptoms typically include:

  • Sneezing
  • Coughing
  • Fever
  • Watery eyes
  • Sore throat
  • Headache
  • Stuffy or runny nose
  • Post-nasal drip

Common cold symptoms are typically milder than influenza or COVID-19; people usually do not become short of breath or have difficulty breathing. However, it is important to note that people who have a mild presentation of COVID-19 or the flu can also appear to have a common cold, says Dr. Darius. "We do know there are people who acquire COVID-19 who are asymptomatic (i.e., have no symptoms); hence, it is imperative not to make assumptions based on symptoms alone," she says.

Flu Symptoms

Since the symptoms of the flu and COVID-19 present themselves in similar ways, it's crucial to see a doctor if you are experiencing any of these key symptoms this season:

  • Fever or chills
  • Cough
  • Sore throat
  • Headache
  • Shortness of breath or difficulty breathing
  • Body aches or fatigue

The main difference between the flu and COVID-19 will be evident at the start, when you begin to experience symptoms; monitor how your body responds to them. "With the flu, the symptoms tend to be more sudden in appearance, whereas with COVID-19, it's a bit slower to appear," says Dr. Darius. "Flu symptoms usually respond to antiviral medications like Tamiflu if started at the appropriate time, and most people will recover from the flu in days to less than two weeks."

COVID-19 Symptoms

One of the biggest challenges in differentiating the coronavirus from a cold or the flu is that COVID-19 reveals itself in so many different ways, says Paul Sherman, MD, chief medical officer at Community Health Plan of Washington. These are all common symptoms of COVID-19:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea
  • New loss of taste or smell

However, there is one key trait that is unique to COVID-19, says Dr. Sherman. "The only symptom that can clearly differentiate COVID-19 from a cold or the flu is if a person has new loss of taste or smell," he says. "Another way to potentially differentiate is that cold and flu symptoms usually resolve within a week, so if symptoms last longer, it's probably COVID-19—but waiting more than a week is waiting too long to figure that out."

Preventative Measures

There are several steps you can take to lower your chances of getting a cold, the flu, and COVID-19 this winter, says Carl Cameron, MD, the chief medical officer at MVP Health Care. He suggests "taking preventive measures like wearing a mask, using hand sanitizer, washing your hands regularly, social distancing, and getting a flu shot," he says. Keeping up to date with your COVID-19 vaccinations is also key.

Sanitizing Surfaces

Additionally, Dr. Sherman recommends cleaning and disinfecting any frequently touched surfaces in your home at least once a day, including tables, doorknobs, light switches, countertops, handles, desks, phones, keyboards, toilets, faucets, and sinks. "Use detergent or soap and water prior to disinfection," he says. "Then, use an EPA-registered household disinfectant."

Getting the COVID-19 Vaccine

If you are not immunocompromised, the best way to prevent COVID-19 or severe cases is by getting the vaccine, says Nasia Safdar, MD, Ph.D., a professor of infectious disease at the University of Wisconsin. She explains that the coronavirus vaccine prevents hospitalizations, complications, and death. "Milder breakthrough infections (infections despite vaccines) are very common, and at this point, 80% or so of the population of the U.S. has encountered COVID-19 in one form or the other," she says.

According to the Centers for Disease Control and Prevention, approved COVID-19 vaccines include Pfizer-BioNTech, Moderna, Novavax, and Johnson & Johnson's Janssen. The latter should only be taken in certain situations, including if someone is allergic to the other three vaccines. The general timing for getting a second dose for applicable COVID-19 vaccines is about eight weeks after the first.

Getting the COVID-19 Boosters

Since vaccine effectiveness decreases over time, boosters are an essential way to supplement, says Dr. Safdar. "Current boosters are active against the existing variant, so taking a booster is a good idea at this time," she says. If you have been vaccinated and get COVID-19, the CDC recommends waiting at least three months after your symptoms began before getting your next applicable vaccine or booster.

When to Call a Doctor

If you experience any of the symptoms of a common cold, influenza, or COVID-19 at any point this winter, it's imperative to contact a doctor and get tested immediately, says Dr. Darius. "The clinical features of COVID-19 overlap substantially with influenza and other respiratory viral illnesses, and there is no way to distinguish among them without testing," she says. "People should monitor their symptoms closely and get tested for the flu or COVID-19 as soon as possible."

Comments (1)

Martha Stewart Member
December 23, 2020
In addition, I've been taking Vit C, D3 and Zinc daily and haven't had a cold or flu or covid symptoms in the last year. Hope everyone stays well. Pray for the very sick.