What's The Difference: Covid vs. Common Cold vs. Flu
By Dr. Mehrtash Amini
Winter is the season for colds, flu, and this year, Covid-19. While most cases of all three of these viruses are relatively mild, many people are wondering this year if their seasonal cough might be something more serious.
In this article, we’ll explore the similarities and differences between Covid-19, the common cold, and the flu and explain how to evaluate your symptoms. If you suspect you may be sick with Covid-19, get in touch with a healthcare provider for support.
How are Covid, the Common Cold, and the Flu Similar?
Covid-19, the common cold, and the flu are all a type of respiratory infection. They may share similar symptoms and can transmit from person to person in the same way.
All three viruses can be spread through airborne respiratory droplets or aerosols, released when an infected person coughs, sneezes, speaks, sings, or even breathes heavily. Microscopic aerosols can stay in the air for extended periods and cause transmission in crowded or poorly ventilated spaces. Respiratory droplets fall to the ground quickly but can cause transmission through contaminated surfaces.
Wearing a mask, social distancing, and frequently watching your hands are all effective ways of reducing the spread of colds, flu, and Covid-19.
All three viruses can share similar respiratory symptoms when they cause infection, including cough and congestion. They can also cause fever and associated fatigue, chills, or ill-feeling. In some cases, both Covid-19 and the flu can cause gastrointestinal symptoms like abdominal cramps and diarrhea.
How are Covid, Common Cold, and the Flu Different?
While these diseases can look quite similar, a close look at their symptoms can make it possible to distinguish them apart.
The most distinct difference in Covid-19 symptoms is the loss of taste or smell, which occurs in many cases, and has not been linked to common cold or flu symptoms.
Another important distinction is the “incubation period,” or how long between infection and onset of symptoms. Covid-19 has the most prolonged incubation period of the three, sometimes lasting up to 14 days. Additionally, some people infected with Covid-19 may never show symptoms and yet can still spread the virus. Proper prevention like social distancing and mask-wearing is therefore critical and often life-saving measures.
Symptoms of Covid-19 can range from mild to severe and can appear anywhere from two to 14 days after exposure. Experts believe individuals may be infectious three days before the onset of symptoms. Symptoms can last considerably longer than the flu or cold.
Common symptoms of Covid-19 include:
- New or worsening cough
- Shortness of breath or difficulty breathing
- Temperature equal to or above 38° C
- Feeling feverish
- Fatigue or weakness
- Muscle or body aches
- New loss of taste or smell
- Gastrointestinal symptoms (abdominal pain, diarrhea, vomiting)
- Feeling very unwell
Less common symptoms include:
- Sleep disorders
- Reduced consciousness
Children may have abdominal symptoms and skin changes or rashes. We are still learning about Covid-19, and some people experience other rare symptoms.
Covid-19 symptoms typically resolve within seven to 14 days, but in some cases last for months.
Common Cold Symptoms
Cold symptoms tend to develop within two days of exposure, much quicker than symptoms of Covid-19. Infected people can transmit the virus starting a few days before the onset of symptoms and remain infectious until all symptoms resolve. The peak of transmission tends to be the first two to three days of symptoms.
The most common symptoms include:
- Red eyes
- Sore throat
- Runny nose
Other symptoms may include:
- Stuffy nose
- Watering eyes
- Hacking cough
- Muscle aches
- General ill-feeling
In general, the common cold resolves within two to seven days and is not severe.
Flu symptoms can be very similar to symptoms of Covid-19. Both diseases can be more dangerous than the common cold, and so anyone exhibiting symptoms should immediately take steps to reduce exposure to others. With the flu, people are infectious starting one day before the onset of symptoms and remain so until five to seven days after onset.
Flu symptoms can range from mild to severe and develop within one to four days of exposure to the virus. The flu is usually accompanied by the sudden appearance of:
- Muscle aches and pain
Other symptoms may include:
- Loss of appetite
- Sore throat
- Runny or stuffy nose
- Diarrhea (less common)
- Nausea and vomiting (less common)
Most people will recover from the flu in seven to ten days.
What To Do If You Are Sick
If you suspect you may have been exposed to Covid-19 or the flu, or you are experiencing symptoms, contact a healthcare provider as soon as possible. Health Canada also has a self-assessment tool to find out if you should get a test.
Anyone with symptoms of Covid-19, the common cold, or the flu should isolate at home until they can be tested or until symptoms resolve. You should also self-isolate if you suspect you have been exposed and are awaiting test results. Infection with the common cold is not severe, but anyone with symptoms should be tested to ensure it is not Covid-19 or the flu.
If you are sick and isolated at home, telehealth services like those offered by BeWell Medical are among the best and safest ways to consult with a doctor. Care through a respiratory illness can include taking fever-reducing medicines to help with pain and discomfort, lots of rest, and hydration. Most cases will resolve without emergency medical intervention.
Covid vs. Common Cold vs. Flu: Know the Differences and Help Prevent the Spread
With a vaccine on the horizon, experts are hopeful this will be the only winter with a severe threat of Covid-19. However, as we wait for a solution, we can all be part of preventing the spread of illness this season.
Understanding the similarities and differences between Covid-19, the common cold, and the flu is an essential first step in doing our part for prevention. Everyone should be monitoring themselves for symptoms regularly and taking steps to reduce exposure to themselves and those around them.
With cooperation and understanding, we can all participate in protecting our neighbours and enjoying this holiday season.