A flu virus is classed as a pandemic when:
• a new type of the flu virus develops
• most people have no immunity against the virus – this means they may not be able to fight the infection
• humans are affected and can pass the flu virus on to others
• the virus spreads quickly and easily around the world
An epidemic is when more people are affected by a disease than usual. A pandemic is a worldwide epidemic.
Pandemic flu is similar to seasonal flu – the
normal type of flu that tends to happen at around the same time every
year – but the symptoms can be more severe. This is because few people
will be able to fight off the infection easily, as it is significantly
different to previous strains of flu they have had.
More people are infected with the flu virus during
a pandemic than are affected by seasonal flu. Seasonal flu tends to
affect people in the winter, but pandemic flu can happen at any time of
the year.
In the twentieth century there have several flu
pandemics, including the Spanish flu outbreak in 1918 and 1919 that
killed millions of people around the world. In 2009 there was a flu
pandemic of the H1N1 flu virus (swine flu).
It’s difficult to predict when a pandemic will
happen, which virus might cause it or how many people might be affected.
Pandemic flu can affect anyone, even the fit and healthy.
Symptoms of pandemic flu
When you catch flu, it usually takes two to three days for your symptoms to show.
Pandemic flu usually causes the same type of
symptoms as seasonal flu. Flu viruses grow in the soft, warm surfaces of
your nose, throat, sinuses, airways and lungs, so this is where you
usually get the symptoms. The symptoms of flu include:
• a fever (high temperature between 39ºC and 40ºC)
• a blocked or runny nose
• sneezing
• headache
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