Flu viruses mutate all the time, usually the changes are minor (known as seasonal drift). However every once in a while a whole new subtype of flu virus appears (known as a shift) and because it is a new flu virus people do not have immunity against it.
When a new flu virus appears there is a possibility for a pandemic to occur as no-one as yet has immunity against it .
With new flu viruses social distancing and community mitigation (ie school closings) are often implemented as crucial tools to help prevent the spread of the virus. It is especially important when the severity of the virus or how easily it is spread is unknown, or when it is known to be a virus capable of causing severe illness.
As with the seasonal flu, basic health practices, such as hand washing. covering your cough or sneeze etc. also help prevent the spread. (See side link on basic health Measures).
A pandemic occurs when:
• A new flu strain occurs.
• Humans lack immunity against it.
• There are simultaneous epidemics around the world.
• The disease is easily transmitted person to person.
• It causes significant illness / death
H5N1(avian flu) and H1N1 (swine flu) have been in the news as both are new flu strains. H5N1 (avian flu) can cause severe illness, but as yet has not been easily transmitted from human to human. H1N1 (swine flu) is easily transmitted human to human but so far causes a flu illness much like the seasonal flu. However, it is unknown how H1N1 will react next flu season as the virus could mutate and become stronger (meaning more virulent and capable of causing a more severe illness) or it could become weaker.
The Word Health Organization (WHO) has 6 levels for a pandemic.
Level 1 = Inter pandemic phase - low risk of human cases.
Level 2 = New virus in animals, no human cases. Higher risk of human cases.
Level 3 = Pandemic alert. No or very limited human to human transmission.
Level 4 = New virus causes human cases. Evidence of increased human to human transmission.
Level 5 = Evidence of significant human to human transmission.
Level 6 = Efficient and sustained human to human transmission.
The WHO currently has the alert level at 5, meaning a pandemic is imminent. As it is unknown how H1N1 will progress it recommended that families and communities learn about preparing for a pandemic flu outbreak, and stay abreast of current updates from both the federal government Center for Disease Control (CDC) and the Michigan Department of Community Health(MDCH).
It is also recommended families know and practice basic hygiene measures, and have a family plan in place in case of a pandemic flu outbreak.
There are many resource links (see box to the side) to become educated about pandemic flu, avian flu (H5N1), and swine flu (H1N1).