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H1N1 and Pandemic Influenza
Pandemic influenzaSeasonal vs. pandemic influenza
When to seek medical attention
Pandemic influenza
An influenza pandemic is a widespread outbreak of disease that occurs when a new influenza virus appears that people have not been exposed to before. Pandemics are different from seasonal outbreaks of influenza. Seasonal influenza outbreaks are caused by viruses similar to ones people have already been exposed to; flu shots are available to prevent widespread illness and impacts on society are less severe. Pandemic influenza can cause serious illness because people do not have immunity to the new virus. Pandemic flu spreads easily from person to person and can cause serious illness because people do not have immunity to the new virus.
A pandemic may come and go in waves, each of which can last for months at a time. Everyday life could be disrupted due to people in communities across the country becoming ill at the same time. These disruptions could include everything from school and business closings to interruption of basic services such as public transportation and health care. An especially severe influenza pandemic could lead to high levels of illness, death, social disruption, and economic loss.
For a new influenza virus to cause a pandemic, it must be able to:
- Infect people (not just animals and birds)
- Cause illness in large numbers of those infected
- Spread easily from person to person
As per the Key Planning Assumptions in The Canadian Pandemic Influenza Plan for the Health Sector, the influenza pandemic will occur in two or more waves (each wave lasting 6-8 weeks) and the pandemic will last 12-18 months. It is anticipated that the majority of cases will occur in the first wave.
Seasonal vs. pandemic influenza
Seasonal influenza is a respiratory illness, caused by the influenza virus that affects many Canadians each year. Influenza viruses are easily passed from person to person. Although most people will recover completely, 4,000 to 8,000 Canadians actually die every year from influenza and its complications.
Pandemic influenza is a new strain of influenza that people have no protection against. The disease spreads easily from person to person and an effective vaccine is not immediately available.
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| Seasonal Influenza (The Flu) | Pandemic Influenza |
| Occurrences | Occurs every year during the winter months | Occurs three to four times a century and can take place in any season. |
| Infection Rate | Affects 10 to 25 per cent of the Canadian population | Experts predict an infection rate of 25 to 35 per cent of the population, depending on the severity of the virus strain. |
| Fatality Rate | Globally, kills 500,000 to 1 million people each year, 4,000 to 8,000 in Canada. | The worst pandemic of the last century, the Spanish Flu of 1918, killed 30,000 to 50,000 in Canada and 20 to 40 million people worldwide. |
| Recovery | Most people recover within a week or two. | Usually associated with a higher severity of illness and, consequently, a higher risk of death. |
| Groups at Risk | Some people 'at risk' for serious complications of influenza include:
| All age groups may be at risk for infection. Otherwise fit adults could be at relatively greater risk, based on patterns of previous epidemics. For example, adults between the ages of 20 to 40 (a key segments of the Canadian workforce) were disproportionately affected during the 1918 pandemic. |
| Prevention | Annual influenza immunization is effective because the virus strain in circulation each winter can be fairly reliably predicted. | A vaccine against pandemic influenza will not be available at the start of a pandemic. New strains of viruses must be accurately identified, and producing an effective vaccine could take four to six months. |
| Treatment | Anti-viral drugs are available for those most at risk of becoming seriously ill. | Anti-viral drugs may be in limited supply and their effectiveness will only be known definitely once the pandemic is underway. |
A Historical Perspective
Previous influenza pandemics affected large numbers of the population, caused many deaths and resulted in severe economic and social disruption.
Spanish Flu
Year: 1918-1919
Estimated deaths: 20-40 million (global)
Age groups most affected: Healthy young adults (20-50 years)
Likely origin: Uncertain
Asian Flu
Year: 1957-1958
Estimated deaths: 1 million (global)
Age groups most affected: Very young and very old
Likely origin: China
Hong Kong Flu
Year: 1968-1969
Estimated deaths: 1-4 million (global)
Age groups most affected: Very old and those with underlying medical conditions
Likely origin: China
H1N1
H1N1 Flu Virus is a strain of the influenza virus that usually affects pigs, but which may also make people sick. H1N1 flu virus is a respiratory illness that causes symptoms similar to those of the regular human seasonal flu. H1N1 Flu Virus has been reported around the world, and the World Health Organization has declared it a pandemic influenza virus.
The World Health Organization (WHO) estimates that this influenza pandemic could infect 15 to 30 per cent of the world's population. An influenza pandemic will probably be made up to two to three waves of illness. Each wave will last six to eight weeks and the waves will be separated by three to nine months.
How influenza spreads
Influenza is highly contagious and spreads very quickly especially in crowded placed. The influenza virus enters your body through your nose or throat when you:
- breathe in droplets produced by the coughing or sneezing of people who are already infected with the flu.
- touch your mouth, eyes or nose after:
- hand-to-hand contact with infected people who have not washed their hands.
- touching surfaces or handling objects contaminated by infected people.
The H1N1 flu virus can live outside the body on hard surfaces, such as stainless steel and plastic, for 24 to 48 hours and on soft surfaces, such as cloth, paper and tissues for less than 8 to 12 hours; however, it can only infect a person for up to 2 to 8 hours after being deposited on hard surfaces and for up to a few minutes after being deposited on soft surfaces.
Preventing H1N1
The most effective way to protect yourself and others from influenza is to remember the three C's - Clean, Cover and Contain.
- Clean your hand regularly with soap and water or hand sanitizer.
- Use a tissue or your arm to cover coughs and sneezes.
- Contain your illness by staying home and resting.
These three principles of personal hygiene will help keep you healthy and prevent the spread of bacteria and viruses to other people. Other things you can do to prevent the spread of H1N1 are:
- Avoid touching your eyes, nose or mouth.
- If you blow your nose, carefully and promptly throw the tissues away into the garbage.
- Frequently clean and disinfect household surfaces such as door knobs, light switches and countertops that may have been contaminated.
- Avoid mass gatherings as much as possible.
- Encourage all members of your household, especially children, to follow these practices.
How influenza makes you feel
Common symptoms of influenza include:
- Fever
- Cough
- Headache
- Muscle aches
- Joint pain
- Sore throat
- Lack of appetite
- Fatigue
- In the case of H1N1 influenza, some people have also reported vomiting and diarrhea.
People with influenza can spread it to others from the day before they feel sick up to seven days afterwards. Once you are infected with the influenza virus, it usually takes from one to three days before you feel ill. Most flu symptoms usually last four to seven days, although a cough and general fatigue may persist for several weeks afterward.
When to seek medical attention
If symptoms worsen or if there are other health concerns, call a health care professional for advice. Some of the signs that can signal progression to more severe disease include:
- Shortness of breath, either during physical activity or while resting.
- Difficulty breathing.
- Turning blue.
- Bloody or colored sputum (saliva/spit).
- Chest pain.
- Altered mental status.
- High fever that persists beyond three days.
- Low blood pressure.
In children, signs that can signal progression to more severe disease include:
- Fast or difficult breathing.
- Lack of alertness.
- Difficulty in waking up.
- Little interest in play.
Impact on health services
An influenza pandemic will place considerable pressure on health and social services. An increased number of patients with influenza will require treatment both in the community and in hospital. There will be a reduced workforce due to illness and the general disruption that is likely to occur.