Influenza, just like the common cold, is a viral respiratory infection that affects the nose, throat and lungs.
Viruses are spread from person to person through airborne droplets that are sneezed out or coughed up by an infected person. In some cases, the viruses can be spread when a person touches an infected surface (e.g., doorknobs, countertops, telephones) and then touches his or her nose, mouth, or eyes.
The difference between influenza and the common cold
Influenza- commonly referred to as 'the flu."
The peak time for the flu is November to April which is called the flu season. Hospitalization and death can occur due to the flu mostly among high-risk populations, such as those with medical conditions (diabetes or cancer) or weakened immune systems, seniors or very young children.
There are three types of influenza viruses; A, B and C. Type A influenza causes the most serious problems in humans.
Common Cold- there are over 200 different known cold viruses. In Canada, the peak times for colds are at the start of the school year in the fall, in mid-winter, and again in early spring.
Children catch approximately eight colds per year, adults about four, and seniors about two.
Many people confuse the flu with a bad cold. The following table highlights the differences between influenza and the common cold:
|Fever||Usually present, high (102°F to 104°F or 38°C to 41°C); lasts 3 to 4 days.||Uncommon|
|Headache||Very common (can be severe).||Uncommon|
|Aches & Pains||Common and often severe.||Slight|
|Fatigue & Weakness||Starts early, can be severe, and can last up to 14 to 21 days.||Mild|
|Extreme Exhaustion||Very common at the start.||Never|
|Chest Discomfort, Cough||Common||Mild to moderate, hacking cough.|
|Complications||Can lead to pneumonia or respiratory failure; can worsen a current chronic condition; can be life-threatening.||Can lead to sinus congestion or earache.|
People infected with an influenza or cold virus become contagious 24 hours after the virus enters the body (often before symptoms appear). Adults remain infectious (can spread the virus to others) for about 6 days, and children remain infectious for up to 10 days.
Testing (Health Care Professionals)
For information and visuals on how to collect a nasopharyngeal specimen for bordetella pertussins or other respiratory viruses, check the Nasopharyngeal Swab (NP) Procedure guidelines.
Symptoms of Influenza
- Sudden onset of fever (with chills) and aching muscles or joints.
- A few hours later, a dry cough, headache, stuffy, running nose and extreme fatigue or tiredness begins.
- Most symptoms last five days or longer.
- Fatigue may linger after other symptoms fade.
What to do if you have the flu
- Stay home until your symptoms begin to go away.
- Cover your mouth and nose with a tissue when coughing or sneezing. Throw the used tissue in the garbage immediately and wash your hands with soap and running water.
- If tissues are not available, cough or sneeze into the upper sleeve or elbow of your clothing to trap the droplets.
- Do not visit people in hospital or in retirement or long-term care homes.
- Wash your hands frequently with soap and warm running water, especially before eating or preparing food, and after blowing your nose or using the washroom.
- Keep an alcohol-based hand sanitizer (gel or wipes) handy at home, work and in your car to clean your hands regularly.
- Get your flu shot
- Immunization for influenza (flu) is recommended because:
- Flu symptoms are more significant than those of a common cold.
- It easily spreads to vulnerable people, including those with chronic illness and the elderly.
- The complications from the flu can be very serious.
The most common side-effects of a flu shot are soreness where the vaccine was injected and sometimes a fever or fatigue. The vaccine cannot cause a person to get the flu, and respiratory symptoms after an injection are likely due to infection with another virus.
To learn about the flu clinics, clinic schedule, location of the clinics, and employer-based clinics go to the Influenza Clinic page.