Are the additives in vaccines harmful?

A vaccine is made up of several different substances and components. Most vaccines need to include additives, to help improve their effectiveness and to increase their shelf life. The three primary substances which are added to vaccines include:

• Adjuvant - this substance helps make the vaccine more effective. It works by stimulating the body's immune system to fight off bacteria and infection more quickly. It means that less of the vaccine has to be administered in order for it to be effective.
• Stabilizer - this additive helps to ensure that the vaccine still works even when it is exposed to changes in environment, such as light and temperature. This means that the vaccine will be able to be stored for longer periods of time.
• Preservative - this substance helps prevent foreign bacteria, or fungi, from contaminating the vaccine. If the vaccine were to become contaminated, it could cause the person taking it to develop a serious infection.

All three of these additives play a very important role in vaccines. The additives in vaccines will pose no risk to your, or your child's, health. The additives tend to improve the safety of a vaccine rather than compromise it. Vaccines always undergo years of development and testing to ensure that they are safe to use.

Some vaccinations may include stabilizers which contain traces of egg protein and gelatin. For example, the measles vaccine contains traces of egg. In very rare cases, this may provoke an allergic reaction. However, the reaction will usually be very mild, and rarely requires treatment. If you are concerned that you, or your child, may be affected by an allergy when taking a vaccine, speak to your doctor for further advice.