Key Facts on H1N1 Flu Virus

Updated: September 2010

In April 2009, the H1N1 flu virus emerged as a new strain of pandemic influenza which differed from the seasonal flu. People had no natural immunity to protect against this virus.  Surveillance of its spread showed that it affected more young and healthy people than the regular seasonal flu, which normally affects seniors and young children. People with underlying medical conditions and pregnant women were at a greater risk for severe illness.

On August 10, the World Health Organization declared that the H1N1 pandemic had entered the post-pandemic period.  This decision was informed by epidemiological evidence from around the world showing the H1N1 influenza virus circulating at lower levels and taking on the behaviour of a seasonal influenza virus.

What is it?

H1N1 Flu Virus has been reported around the world and was a strain of the influenza virus that had previously primarily affected pigs. In the Spring of 2009, it emerged in people in North America and spread to humans in regions around the world. This was a new strain of influenza and humans had little to no natural immunity to this virus.  The WHO declared H1N1 a pandemic in June 2009.

Like seasonal influenza strains, the H1N1 flu virus is contagious and can be spread when an infected person coughs or sneezes and the germs enter the nose, eyes, or throat of another person.  These germs can also rest on hard surfaces like counters and doorknobs, and can be picked up on hands and transmitted to the respiratory system when someone touches their mouth and/or nose.  It is not possible to catch it through blood transfusions.

Symptoms

Almost always:

• Cough and fever

Common:

• Fatigue
• Muscle aches
• Sore throat
• Headache
• Decreased appetite
• Runny nose

Sometimes:

• Nausea
• Vomiting
• Diarrhea

More investigation is needed on how long a person can be infectious (be able to spread the virus to others); however, it is believed that this period is for one day before the onset of symptoms and continues for approximately seven days after symptoms have started.  

Prevention

To help minimize the spread of influenza, the Public Health Agency advises Canadians to:

• Wash hands often with soap and warm water for at least 20 seconds, or use hand sanitizer.
• Keep your hands away from your face.
• Cough and sneeze into your arm, not your hand. If you use a tissue, dispose of it as soon as possible and wash your hands.
• Get immunized.
• Keep common surface areas—for example, doorknobs, light switches, telephones and keyboards—clean and disinfected.
• Eat healthy foods and stay physically active to keep your immune system strong.
• Keep doing what you normally do, but if you get sick, stay home.
• Check www.fightflu.ca (External link) for more information.
• Check www.voyage.gc.ca (External link) for travel notices and advisories.

Be Prepared

Put together a home preparedness kit before anyone gets sick. When you are sick, you won't want to go out and get groceries or health supplies.

Here are some examples of household items that you may want to have in your home:

• Pain and fever medication, like Tylenol or Advil, to treat fever and headaches
• A thermometer
• Extra supplies of any essential medication, like insulin for diabetics
• Cleaning supplies, like household disinfectant
• Soap and alcohol-based hand sanitizer to keep hands clean
• Non perishable food, like canned soup and fruits and vegetables and liquids, like water and juice, in case you can’t get to the grocery store

Treatment

If you get flu-like symptoms and are otherwise healthy, you should stay home to recover. If your symptoms worsen or you experience difficulty breathing or serious shortness of breath, it is important to seek medical attention.

Antivirals

Antivirals are prescription medications used to treat viral illnesses, including the flu. If taken shortly after getting sick (within the first 24 to 48 hours), they can reduce flu symptoms, shorten the length of illness and may reduce serious complications. They are available in two forms: a pill (called oseltamivir or Tamiflu®) or an inhaler (called zanamivir or Relenza®).

Antivirals are recommended for the treatment of moderate to severe illness, and for people at risk of severe disease. Your doctor will decide if treatment is right for you.

Vaccination

As the circulation of H1N1 influenza in Canada is very low at this time, vaccination against H1N1 is only recommended for travellers visiting areas where H1N1 is circulating. If travellers have previously received the H1N1 vaccine, no further vaccine is needed.

During the H1N1 outbreak in Canada, adjuvanted vaccine was recommended for most Canadians as it provided better protection against H1N1 influenza. However, the adjuvanted vaccine has now expired and is not currently available in Canada.

The H1N1 vaccine currently available in Canada is the Influenza A (H1N1) 2009 Pandemic Monovalent Vaccine (Without Adjuvant). 

For more information

H1N1 Flu Information

Guidance provided during the 2009-10 H1N1 Outbreak

Still have questions? Call 1 800 O-Canada