Cold and Flu: Definition

The cold days of fall announce the start of cold and flu season. Although both of these respiratory infections are caused by viruses, their signs and symptoms are different. Learn about the difference between colds and the flu and how to treat them.

What are colds and the flu?

Each year, the cold weather announces the start of not only autumn but also cold and flu season. Adults get an average of 2 to 4 colds per year, and children get an average of 6 to 10. The flu (or “influenza”) is much less common.

Cold symptoms and flu symptoms

Although these two respiratory infections seem similar, they do have differences.

Flu symptomes Cold symptomes
Sudden onset Gradual onset
Sore throat
Aches, joint and muscle pain Sneezing
Intense fatigue that can last 2 to 3 weeks Nasal congestion, runny nose
Fever: 38 °C to 40°C Fever generally absent or low-grade (38°C)
Intense headaches Headaches are rare or mild
Dry and painful cough Dry or wet cough
Duration: 7 to 14 days Duration: 7 days
Possible complications: ear infections, sinusitis, bronchitis, pneumonia, hospitalization, death 
Possible complications: ear infections, sinusitis, pneumonia

At-risk populations  and conditions that increase the risk of complications:

  • Children under the age of 5
  • Seniors over the age of 65
  • Women who are pregnant or have given birth in the past month
  • Heart or lung disease
  • Diabetes
  • Cancer
  • AIDS (HIV) and other conditions that suppress the immune system 
  • Kidney and liver disease
  • Blood disorders (e.g., anemia)

How to avoid catching or spreading cold and flu viruses

Good hygiene

When someone with a cold or the flu coughs or sneezes, the virus is expelled into the air in fine droplets. You contract the virus by breathing in these droplets or when you ingest the virus from contact with contaminated objects (e.g., door handles, phones or toys). In expelled secretions, cold viruses can survive for up to 24 hours and influenza viruses can survive for up to 48 hours.

Hygiene is key to keeping cold and flu viruses at bay.

  • Make sure you cough or sneeze into a tissue and cover your entire nose and mouth. If you don’t have a tissue handy, cough or sneeze into your elbow.
  • Wash your hands several times a day, especially after you blow your nose or cough, to avoid contracting or spreading a virus.
  • Use a mild soap and thoroughly scrub all surfaces of your hands.
  • Wash your palms, the top of your hands, between your fingers, and under your nails.
  • Dry your hands with a clean towel or paper towel. Wiping will mechanically remove any remaining germs  and is more effective than using a hand dryer. Use the same towel  to turn off the tap and open the bathroom door.
  • Alcohol-based products are effective, but they don't replace good hand washing.

Flu vaccine

Vaccines to prevent the flu are available. The goal of vaccination is to prevent people from contracting the illness and developing complications, such as pneumonia, which can have very serious consequences. 

Vaccinations generally start in November. The vaccine protects you against strains  of the flu virus that experts believe will be more in circulation that year. Full protection begins about 2 weeks after you get vaccinated and lasts for at least 6 months. By getting vaccinated, you are protecting not only yourself but also other people by reducing the risk of transmission.

Almost everyone can get the vaccine, and it is given free of charge to the following people:

  • Children aged 6 to 23 months.
  • People with certain chronic diseases, such as diabetes and chronic obstructive pulmonary disease (COPD).
  • People with immune deficiencies, i.e., people with HIV or cancer or who are taking immunosuppressant drugs.
  • Pregnant women in their 2nd and 3rd trimesters, or, if they suffer from a chronic disease, throughout their pregnancy.
  • People aged 60 and over.
  • People who live in a residential and long-term care centre.
  • The family members  of the people listed above.
  • The family members of infants under the age of 6 months.
  • Health care workers.

Note: People with other conditions may also get vaccinated free of charge. The most common are listed above. To find out if you are eligible for free vaccination or to learn more about vaccinations in general, talk to your pharmacist or doctor or visit the Government of Quebec's Portail santé mieux-être.

Echinacea, ginseng and zinc: Do they really work?

Studies show that echinacea has a minimal effect at preventing or treating the common cold. Although the evidence is inconsistent, studies that do show an effect of echinacea i ndicate that it may reduce the duration of a cold by about half a day to just over a day. The different parts of the plant used to make the extracts and a lack of product control are some reasons for echinacea’s inconsistent health effect.

The effectiveness of ginseng and zinc is also controversial, and these substances can interact with your existing medications. 

Always consult your pharmacist before using natural health products to avoid taking these products unnecessarily and to ensure they don't make your condition worse.

Cold and flu treatment

Colds and the flu usually go away by themselves in 7 to 14 days without medication. However, if your cold or flu won't go away or your symptoms get worse, you will probably need to see a doctor. If you aren’t sure, ask your pharmacist.

Below are some cold remedies and flu remedies that can relieve your symptoms:

  • Get plenty of rest.
  • Eat healthy foods.
  • Drink 6 to 8 glasses of water per day.

Should I take antibiotics?

An antibiotic is an anti-infective agent that kills harmful bacteria in the body. However, colds and the flu are both caused by viruses. Since viruses are a completely different type of micro-organism compared to bacteria, antibiotic treatment is ineffective at treating them

However, colds and the flu can have complications that lead to bacterial infections, such as ear infections, bronchitis, sinusitis or pneumonia. In this case, your doctor may decide to prescribe an antibiotic.

Flu antivirals: Are these effective?

Flu antivirals help limit the spread of the influenza virus, decrease the duration of the flu, reduce the severity of flu symptoms, and decrease flu-related hospitalizations. To be effective, flu antivirals need to be taken as soon as the first flu symptoms appear. The decision to use antivirals is a personal one.

How to relieve cold symptoms and flu symptoms

Nasal washes, tablets, syrups, lozenges—there is no end to the available products to treat cold and flu symptoms. Consulting your pharmacist about cold and flu medication is a smart thing to do, even when the product seems harmless.

First, like all over-the-counter or prescription drugs, cold and flu medications can cause side effects. They may also contain ingredients that can interact with or change the effect of your medication. You also need to avoid taking products that contain similar ingredients, as large accumulated doses of the same substance can cause severe side effects or serious health problems. Overall, you should talk to your pharmacist to make an informed choice.

If you decide to take something to relieve your symptoms, you should use a product with a single active ingredient to relieve one specific symptom at a time. All-in-one products that combine multiple ingredients for multiple symptoms are rarely sufficient. When you take these combination products, you may be taking unnecessary medication, which increases the risk of side effects.

Tips for choosing a cold or flu medication

Here are a few tips to help you choose the best cold and flu medication for you.

To relieve cough

Coughing is the body’s natural defence mechanism to eliminate secretions that block the airways and lungs.

  • If you have a productive cough, don’t take a cough suppressant, as this can prevent your body from naturally getting rid of microbes in your airways and can promote infection.
  • If your secretions are yellow or green, this is a probable sign of infection, and you should consult a doctor.
  • If your cough is dry (i.e., it tickles or irritates your throat), solutions that contain dextrometorphan (DM), chlophedianol or codeine may be a good option for you.


DM, chlophedianol and codeine are contraindicated if you are taking certain medications. People with diabetes also need to check the sugar content of cough syrups. Consult your pharmacist to ensure that these products won’t interact with your medication or that any health problems you have won't prevent you from taking them.

To relieve nasal congestion

There are three types of products to relieve nasal congestion.

  • Pseudoephedrine and phenylephrine are decongestants found in syrups, tablets, capsules and hot liquid medicines. These stimulants can cause insomnia, palpitations, headaches and tremors.
  • Decongestants in the form of nasal sprays or drops can be good choices for people who can't take oral decongestants. However, don't use these products for more than 3 consecutive days, as this can lead to “rebound” congestion (caused by the product and not the cold).
  • Sprays or drops that contain only saline (a mixture of water and salt) are better because they can be used often and for an indefinite period. Saline solutions like HydraSenseTM or Sinus RinseTM seem to be more effective at cleaning the nose and decreasing congestion than sprays like SalinexTM.


Pseudoephedrine and phenylephrine must not be used by people who have narrow-angle glaucoma, heart disease, urinary retention and some thyroid gland problems. They must be used with caution if you are diabetic or have hypertension.

Decongestant sprays must also be used with caution by people with hypertension and must be avoided by people experiencing an acute glaucoma attack.

If you are pregnant, you can use decongestant sprays during the 1st trimester. Oral pseudoephedrine is also considered safe during the 2nd and 3rd trimesters. However, non-pharmacological (saline) remedies should be your first choice throughout your pregnancy.

To relieve a runny nose 

Some combinations of cold and flu medications contain antihistamines. These products may relieve a runny nose by helping to dry up nasal secretions. Antihistamines are often found in night medications, as these products cancel out the stimulation of decongestants. For some people, antihistamines don’t cause drowsiness, so the night formula will be just as stimulating for them as the day medication. Use saline solutions to help get rid of mucous.

To relieve sore throat

  • Acetaminophen and ibuprofen are effective at relieving sore throat.
  • Lozenges can also relieve sore throat because they promote saliva production and moisturize the throat.
  • Lozenges with an anesthetic  may help soothe pain. You should take these after eating, as they decrease mouth sensitivity, which increases the risk of burns.
  • No lozenges can get rid of a throat infection. These infections can only be treated with antibiotics. Lozenges that are labelled as “antibacterial” have a bacteria-killing substance, but this is generally not very effective.
  • Drinking cold beverages and eating popsicles or ice cream may help soothe the pain.

To control fever

Acetaminophen and ibuprofen are generally effective at controlling fever. If your body temperature increases even when you use these products at the recommended doses, consult a doctor. 

Caution: Don’t give acetylsalicylic acid to children or teens

You can’t give acetylsalicylic acid (aspirin)  to children or youth under the age of 18, as aspirin use is linked to Reye's syndrome, a rare but very serious health problem.

For more information about how to prevent colds and the flu and your treatment options, consult your pharmacist, who is here to help.

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