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Written by Caidr's team of doctors and pharmacists based in UK | Updated: 04.04.2022 | 2 min read

A vaccine (also known as vaccination, immunisation, jab) is when your body is given a modified version of a virus or bacteria so that your immune system can develop immunity against it without getting the harmful illness associated with whichever virus or bacteria it is. This is usually in the form of a small injection and is why it is also known as a "jab" and tends to be given into the muscle in your upper arm.

Vaccines have been key in preventing serious and potentially fatal infectious diseases. There are also seasonal vaccines such as the flu vaccine and travel vaccines that you will only require if you are travelling to certain places abroad where some diseases are more prevalent than in the UK. There are also specific vaccines such as hepatitis depending on your risks of exposure to blood-borne viruses.

The bacteria or viruses are made safe for a vaccine by either weakening, changing or killing them so that they cannot cause harm. If a vaccine uses a weakened version of the pathogen (virus or bacteria) then it should be considered whether it is safe to give to people with a lowered immune system.

All approved and licensed vaccines have gone through clinical trials meaning that it has been thoroughly tested and are safe for use. The side effects of vaccines are usually mild and short-lived however in a very small number of people, a severe allergic reaction can occur known as anaphylaxis. It is not common but it is life-threatening and can develop quickly, causing the swelling of airways and difficulty breathing along with other symptoms such as feeling faint or dizzy, feeling sick, and collapse. Any signs of anaphylaxis should be responded to by calling 999 immediately.

Routine vaccines

There are many vaccinations that are offered as a matter of routine here in the UK. They come at different ages, and on a standard protocol throughout childhood. This is known as the childhood immunisation programme and includes vaccinations such as immunity to meningococcal bacteria, measles, mumps, rubella, rotavirus and more.

Caidr pharmacists' top tips

If you are travelling abroad, you can seek advice from your pharmacist about what precautions or vaccinations you may need. You can also book a travel appointment with your doctor or at private clinics. It is best to do this at least 2 months before when you plan to travel.

When should I see my doctor?

If you or your children have missed any routine vaccinations for any reason then it is important to book a routine doctor's appointment. If you have had an allergic reaction to a vaccine in the past or have a severe egg allergy it is best to check with your doctor prior to having any vaccines as to whether it is safe for you to have it (some vaccines contain egg proteins in them).

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