Home COVID-19 Pandemic Is your cough COVID, a cold or the flu? How to tell the difference

Is your cough COVID, a cold or the flu? How to tell the difference

by Matthew Best

Coronavirus and influenza threaten a ‘twindemic,’ symptoms can be confused

Coughs come with coronavirus, influenza and the common cold, but there are ways to tell those coughs — and other symptoms of the three infections — apart thanks to information from Health Canada and other health organizations. (Adobe Stock)

As health experts worry over the possible “twindemic” of COVID-19 and the regular flu season, here’s how you can gauge your symptoms, along with the ever-present spectre of the common cold. COVID-19 and the flu can both be fatal. COVID-19 has killed over 9,500 people in Canada and the flu kills an average of 3,500 Canadians a year, according to Health Canada. The common cold rarely causes fatal complications, except in unique circumstances such as recent bone marrow recipients.

The three diseases are caused by different viruses — in the case of the flu and the cold, by several different viruses — and understanding what sets them apart is important to understanding your own symptoms and whether you should go for testing.

Health Canada, the World Health Organization and the American Center for Disease Control, among others, provide information on distinguishing one virus from another, but those factsheets are often spread out. We’ve aggregated that information here.

Distinguishing symptoms

With so much in common between the viruses, it’s no surprise that the diseases share many symptoms. For example, all three diseases produce a cough. But the flu and COVID-19 are more typically dry, racking coughs, while the cold usually produces a wet, phlegmy cough.

Severe; up to two weeks’ incubationRapid onsetGradual onsetOnsetCommonCommonRarelyFeverNoNoCommonSneezingCommonOccasionallyOccasionallyLoss of taste/smellOccasionallyCommonCommonAches and painsRarelyOccasionallyCommonRunny noseOccasionallyOccasionallyCommonSore throatOccassionallyCommonRarelyHeadacheOccasionallyNoNoShortness of breathNoOccasionallyNoVomitingRarelyOccasionallyNoDiarrheaCommon; usually dryCommon; usually dryCommon; usually wetCoughingOccasionallyCommonOccasionallyFatigueSymptomFluColdCOVID
Ryersonian graphic. Data from WHO, Health Canada and the CDC.


COVID-19 is caused by SARS-CoV-2. The confusingly similar names refer to the disease and the virus that causes it, respectively. COVID-19, short for coronavirus disease 2019, is our current disease outbreak and refers to the cluster of symptoms people experience when infected with the virus. That virus, SARS-CoV-2 (short for severe acute respiratory syndrome coronavirus two) is the specific virus that caused the pandemic. It’s closely related to the virus that caused the SARS outbreak in 2003.

The most common symptoms of COVID-19 are a dry cough, fever, and a loss of a sense of taste and smell. Shortness of breath is less frequent but also present in COVID-19. Shortness of breath shouldn’t be confused with catching one’s breath after a coughing fit, but a constant difficulty breathing.

Symptoms have an escalating, severe onset after an average incubation period of five days. However, the incubation period can last up to two weeks, hence Canada’s 14-day isolation policy for people exposed to COVID-19 or returning from abroad.

Children might also experience “COVID toes,” bluish-red or purple lesions on the feet and hands.

The flu

Influenza — commonly known as the flu — is the seasonal viral outbreak that keeps us out of work and our kids home from school. Like COVID-19, the flu is the name for the immune response people put up when fighting the viruses which cause the disease. Unlike COVID-19, influenza is caused by many different types of viruses. Those viruses fall into influenza types A, B and C. Under each of those types are even more types, such as H1N1 (a type of swine flu).

The most common symptoms of the flu are a fever, headaches and body aches, a dry cough, and fatigue. People with the flu might also experience diarrhea, vomiting and nausea.

Coughing fits from the flu can leave you temporarily short of breath, but the shortness of breath isn’t persistent.

Flu symptoms usually have a rapid onset and disappear within a week or less.

The common cold

Even more general is the common cold. Unlike COVID-19, which is caused by just one virus, and the flu, which is caused by an influenza virus, the common cold is caused by many different families of viruses. The most common cold viruses are rhinoviruses. The common cold can also be caused by coronaviruses other than SARS-CoV-2 and even influenza viruses.

Like COVID-19 and the flu, the cold produces a cough. But the common cold cough is frequently phlegmy as the body attempts to rid the airways of nasal drip. That nasal drip goes hand-in-hand with the cold’s other frequent symptoms: sneezing and a runny nose. And, like the flu, the cold can often bring joint and body aches, though they’re often milder than the flu’s aches. It rarely has a fever, and vomiting is usually only caused by swallowing too much phlegm.

Cold symptoms come on gradually and frequently linger, with symptoms peaking at seven to ten days. Sometimes symptoms can linger up to three weeks.

If you feel sick

The symptoms are similar enough that even Canadian schools — a major concern in the second wave — were recently debating removing symptoms of the common cold from their COVID-19 screening checklist to prevent testing centres from being overrun with seasonal sniffles.

Ontario recently announced a shift away from asymptomatic testing to target those most at risk, including school kids. Queen’s Park says you should only seek testing at an assessment centre if:

  • You are showing COVID-19 symptoms
  • Have been exposed to a confirmed case of the virus, as informed by your public health unit or exposure notification through the COVID Alert app
  • You reside or work in a setting that has a COVID-19 outbreak, as identified and informed by your local public health unit
  • You are eligible for testing as part of a targeted testing initiative directed by the Ministry of Health or the Ministry of Long-Term Care

With so many overlapping symptoms and guidelines, what are you supposed to do? Federal and provincial guidelines haven’t changed that much. As always, both Health Canada and the Province of Ontario advise you to isolate for 14 days if you’ve been exposed to somebody with COVID-19 or are returning from abroad to see if symptoms develop and stay home to manage mild symptoms.

This article may have been created with the use of AI software such as Google Docs, Grammarly, and/or Otter.ai for transcription.

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