Is it too late to get the flu vaccine? Does it work? We've answered your questions on flu!

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Who should get the flu vaccine?

There's nothing like flu for ruining your Christmas. Flu, unlike a cold, isn't something you can just shake off and power through. It's a really nasty illness that can leave you feeling under the weather for some time. Flu can have complications, that may be very serious. Some people are more vulnerable to serious complications from flu, especially the elderly, pregnant women, the very young, and those with previous problems with their lungs such as asthma and COPD. It is also a good idea to protect yourself from flu if you work with people, or have family that are vulnerable to the disease.

I had the flu jab last year, why do I need it again?

The flu virus is very clever, and constantly mutates. A vaccine is, in essence, a practice run for your immune system, enabling it to quickly and efficiently deal with the real disease if you come into contact with it again. Vaccines are the single biggest life saver out there, but they rely on the target staying relatively stable. 

Is it too late to get the flu vaccine?

Most seasonal flu outbreaks peak in the winter months of December-February, however, they can start as early as late September and carry on as late as May. It is best to get the flu jab in early October, so you're protected for as much of the flu season as possible, but if you've escaped the flu so far, there is no problem with having the vaccine a bit late. It should give you protection until this season is over! If you're in one of the vulnerable groups, it's a really good idea to have the vaccine and better late than never!

Does the vaccine work?

All year long, 142 influenza centres across 113 different countries collect data about the different strains of flu virus that are circulating. They look hard at which strains are making people sick, how severe they are, how they are spreading, and how well previous vaccines have worked. All of these 142 organisations pass on their data to one of the five major World Health Organisation centres: the CDC in the USA; the National Institute of Medical Research in the UK; the Victoria Infectious Diseases Referemce Laboratory in Australia; the National Institute for Infectious Diseases in Japan; and the National Institute for Viral Disease Control and Prevention in China. Scientists from these five insututions then get together, analyse the data, and identify new strains of flu, and determine which strains they think will cause a problem the next winter. It isn't an easy task, however, most years they get it right. Occasionally something happens that they don't forsee, and we end up with a flu vaccine that doesn't protect properly against the strains of flu that are circulating. This happened in 2016, leading to lots of headlines stating that the flu vaccine was useless. While the 2016 vaccine wasn't good, in most years the flu vaccine is highly effective at preventing flu. 

Why are flu viruses called H something N something?

Each virus particle is roughly circular, and it coats itself with a cell membrane from your own cells, so it can hide from the immune system. To infect a cell it has to stick to the surface so, poking out of the cell membrane, are spikes called haemagglutanin (HA) and neuraminidase (NA). The name of the flu subtype are taken from which HA and NA are present, so bird flu is H5N1, and swine flu was H1N1.