It’s a cold Saturday morning in late November, my iPhone tells me that it is currently 0°C and I can see fog out of my window. Autumn is over, and winter is finally here (not to mention Christmas). The Starks will be happy….
With the arrival of winter comes other delights, snow, Brussels sprouts (a debatable delight) and the seasonal flu.
In the UK, the NHS offers a yearly flu jab for those who are deemed ‘at risk’ – those who have weakened immune systems such as the elderly, those who have on going medical issues (including HIV) and pregnant women.
This year, at the advice of World Health Organisation (WHO), three viruses are included in the vaccine:
- H1N1 = swine flu (also known as Spanish flu)
- H3N2 = a flu that affected birds and animals in 2011 (also known as Hong Kong flu)
- B/Wisconsin/1 = an active flu strain – this B virus affect humans only
But why is a flu vaccine needed every year?
First of all, the flu, full name influenza, is caused by a virus. Viruses, in the same way as bacteria and even humans, are highly adaptable. Different viruses adapt at different rates, a prime example of which is the HIV virus, which mutates and changes so fast that treatments quickly become obsolete.
The influenza virus changes year on year, causing an epidemic every winter. This is due to a process called antigenic drift, where a spontaneous mutation in the genes encoding the H (haemagglutinin) and N (neuraminidase) glycoproteins occurs. They simply change parts of the virus that would be recognised by the immune system, allowing them to work undetected for the time being.
Of the three previously mentioned viruses, one of these will dominate each year, but as we are currently unable to predict which will cause an epidemic, all three are included as a preventative measure. In those with weakened immune systems, the vaccine will ensure that their immune system is ready to recognise the virus and act against it, should they come into contact with it.
The vaccination itself has an effectiveness of about 70%, but lasts for one year only. After it is administered, people may experience soreness around the area of administration and even some mild flu like symptoms.
For more information about the winter vaccine, follow this link to the NHS Choices page.
Warning: don’t confuse the flu with the common cold. A cold may make you feel a bit off, and the virus that causes it also mutates very quickly (hence why the cure always evades us). But the flu makes you feel far worse, here are some of the symptoms: