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Q&A on vaccines

Revised on 15 November 2011 

Should I be vaccinated against influenza?

For people in a Risk Group the single most important way of preventing the serious complications of influenza is the annual flu vaccine early in the autumn. If you are in a risk group you should take up the opportunity to be vaccinated: this will help prevent you from catching flu, and if you do still catch the infection it is likely to be less severe if you have been vaccinated.

What are Risk Groups?

Risk Groups comprise people who if they become infected with influenza are more likely to experience severe disease than other people. ECDC provides guidance on who is in these groups in Europe. A common listing is:

  • Adults and children with chronic ill health of almost any sort;
  • Older people (65 years and older);
  • Pregnant women.

More precise definitions are determined by national authorities.

Should front line health care workers also be vaccinated against influenza?

Yes – The prime reason is because if they become infected they may pass their infection onto vulnerable patients in the Risk Groups. So really there is a duty of care for health care workers with patient contact to be immunised in the same way they are often immunised against Hepatitis B.

In addition health care workers are often exposed to influenza from their patients. Though if they are infected they at usually no more particular risk of becoming severely ill than other adults of the same age. However it is reasonable that they should be given the vaccine. Hence most employers of health workers make it freely and readily available to their staff.

Does influenza vaccination work, and how well does it work?

Yes – immunization is the single most effective way of protecting against influenza. It reduces the risk of getting influenza and if you still catch the infection you are likely to get it more mildly than if you had not been immunized.

Determining exactly how well immunisation works is not easy as it is variable. For example the vaccine works less well in older people. Also there are years when the circulating viruses are not matched by the vaccine and it works less well. 

Is seasonal influenza vaccination safe and what are the side effects?

We have been using influenza vaccine for decades and we know that it’s one of the safest vaccines around. Certainly for those for whom vaccination is recommended (the Risk Groups) it is more risky to not be immunized (and so risk catching influenza badly) than having the vaccine. All vaccines have some side effects mostly mild like soreness where the injection was given and feeling a little unwell afterwards.  

Can’t you catch influenza from vaccination?

No – definitely not. This story is an example of a vaccination myth. What has probably happened is that someone has happened to be developing influenza as they were immunized and then they have presumed the two events are connected. The story has started either in that way or because unfortunately some people mistakenly call colds ‘flu’.

Why are immunizations given annually?

That is for two reasons. Firstly the exact mix of the influenza viruses changes from year to year and so the vaccine is altered annually to match it. Also immunity from vaccination weakens over time so an annual boost helps.

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