One or two: common cold or the flu?

Recognizing the differences between the common cold and the flu

It’s that time of the year again, when the leaves turn to that lovely orange and the soft scent of warm, fall spices fills our homes. Unfortunately, these changes also herald the start of the cold and flu season, giving many the sniffles and other unpleasant symptoms. Let’s take a closer look at the common cold and seasonal flu, and compare these two conditions.

The common cold

As its name suggests, common cold infections occur frequently and have a large impact on our day-to-day lives. They’re estimated to cause about 40% of time lost from work and 30% of school absences.¹ Infections typically occur between the fall to spring season, depending on the virus. There are over 200 types of viruses that lead to common cold infections.¹

Symptoms will vary from person to person. Many will notice a sore throat at first, followed by other symptoms like a cough, a runny or stuffy nose, and sneezing.¹ Fevers tend to be common in children, but are rare in adults.¹ The infection tends to be at its worst around days 2 to 4, and should begin to clear by day 7, though in some cases it can last up to 2 weeks.¹

The flu (influenza)

The flu, or influenza, shares many similar characteristics with the common cold. It’s also caused by viruses during fall and winter.² There are two main types of flu viruses. They tend to mutate frequently, leading to variants.² In fact, the H1N1 pandemic in 2009 was caused by a specific type of flu virus.³

Much like the common cold, the seasonal flu infection can lead to a variety of respiratory symptoms, including fever, cough, sore throat and runny or stuffy nose.² However, you’re more likely to feel muscle aches, pain and chills, compared to the common cold.² Children, and less frequently adults, may experience diarrhea, nausea or vomiting.² Symptoms start 1 to 4 days after being infected, and people usually recover within 7 to 10 days.²

Comparing the cold with the flu

It may be difficult to determine whether you have the cold or the flu. This chart shows the main differences between these two infections:^4,5

Signs and Symptoms	Common Cold	Flu
Symptom onset	Gradual	Abrupt
Cough	Mild-to-moderate; cough is usually dry at the beginning and becomes wet as the cold progresses	Common; cough remains dry
Fever and chills	Rare (more common if younger)	Common
General aches and pain	Rare	Common
Headache	Rare (usually due to sinus congestion)	Common
Nasal congestion	Common	Rare
Sneezing	Common (at beginning)	Sometimes
Sore throat	Common (at beginning)	Sometimes

If you notice any of the following symptoms, you should speak with your doctor:⁴

• High fever (over 40.5oC)
• Fever (over 38.5oC) for longer than 72 hours
• Severe headache, neck pain or stiffness, or unusual sensitivity to light
• Difficulty breathing, wheezing, or chest pain when breathing
• Prolonged nasal congestion (for more than 7 days) with off-coloured and thick discharge, facial pain, or sinus pain
• Cough for longer than 3 weeks
• Severe throat pain
• Difficulty swallowing and/or painful swallowing
• Signs of dehydration in an infant (i.e., crying without tears, or soft, sunken spots on skull)
• Cold or flu-like symptoms if you have long-term lung disease (e.g., COPD, asthma) or in an infant (less than 3 months of age) with fever

The impacts of the flu

While the common cold and flu share so many similarities, it’s important to know their differences. The flu tends to be more severe, and it shows in the numbers. Every year, the flu leads to over 10,000 hospitalizations and thousands of deaths in Canada.² In fact, it’s among the top 10 leading causes of death in the country.² Common colds tend to be milder than the flu and rarely cause complications.⁵

People in the groups listed below are more likely to be at risk of complications from the flu:²

• Pregnant individuals
• Those with medical conditions, such as
  • Heart disease
  • Lung disease
  • Diabetes
  • Obesity
  • Anemia
  • Cancer or other conditions that weaken the immune system
  • Kidney disease
  • Neurological or neurodevelopmental conditions
  • Children up to the age of 18 years taking ASA (Aspirin®) long-term
• People above the age of 65
• Children under the age of 5
• Those living in a nursing home or long-term care facility

If you have the flu, it’s important to get plenty of rest and fluids as your body recovers.² You may also find it helpful to take pain or fever reducing medications if those symptoms are present.² If you are feeling severely ill or are part of a high-risk group, let your doctor know.² Furthermore, staying home and self-isolating can lower the chance of spreading it to others at home, at school or at your workplace.

Visit our guide to learn more about products and strategies to treat your cold and flu symptoms. Speak with a Rexall® pharmacist if you would like further help in assessing your symptoms. They can also find suitable over-the-counter products to relieve your symptoms.