Is vaccination safe?
Vaccines have to be thoroughly tested for safety before they're made routinely available.
Each vaccine's safety is continually monitored, even after it's been introduced.
This is because not all side effects are picked up during the vaccine's development, especially if they're very rare.
Vaccines need additives to improve the way they work, increase their shelf life, and make them as safe and effective as possible.
The 3 main substances added to vaccines are:
- adjuvants or enhancers – to make the vaccine more effective
- stabilisers – to stop the vaccine deteriorating when it's exposed to changes in the environment, such as light and temperature
- preservatives – to increase the vaccine's shelf life
Vaccine side effects
The Medicines and Healthcare products Regulatory Agency (MHRA) is the organisation responsible for checking the safety of vaccines that are in general use.
The MHRA collects information on vaccine safety via the Yellow Card Scheme, where anyone can report a suspected side effect to the MHRA.
The MHRA also uses other sources of safety information, including medical literature, safety studies done by vaccine makers, databases that track trends in illnesses, and other worldwide organisations.
Page last reviewed: 2 April 2019
Next review due: 2 April 2022