Vaccines are the most effective way to prevent infectious diseases.

Why vaccines are important

We can be affected by illness and diseases at different stages of life, from childhood to older age. This page explains to you how vaccinations work and aims to answer your questions about each type.

Things you need to know about vaccines
  • help to protect you and your child from many serious and potentially deadly diseases
  • protect other people in your family and community – by helping to stop diseases spreading to people who cannot have vaccines, such as babies too young to be vaccinated and those who are too ill to be vaccinated
  • undergo rigorous safety testing before being introduced – they’re also constantly monitored for side effects after being introduced
  • sometimes cause mild side effects that will not last long – you may feel a bit unwell and have a sore arm for 2 or 3 days
  • reduce or even get rid of some diseases – if enough people are vaccinated
  • do not overload or weaken the immune system – it's safe to give children and adults several vaccines at a time and this reduces the amount of injections needed
  • do not contain mercury (thiomersal)
  • do not all contain animal gelatine, and you can check first with your GP
  • do not contain any ingredients that cause harm – only ingredients essential to making them safer and more effective and only in very small amounts
  • do not cause autism – studies have found no evidence of a link between the MMR vaccine and autism