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HealthInfo Waitaha Canterbury

Vaccination safety

Children running n the sunshine All vaccines used in New Zealand have been thoroughly tested to be sure they're safe. While vaccines can cause a reaction, most reactions are short-lived and minor such as a fever or sore arm.

It's rare to have a serious reaction following a vaccination. You're far more likely to be seriously injured by a vaccine-preventable disease than by a vaccine. The benefits of vaccination greatly outweigh the risk, and without vaccines many more disabilities and deaths would occur.

Risk of getting the disease

You cannot get the disease from the vaccine. Vaccines stimulate your immune system to produce an immune response similar to a natural infection but they do not cause the disease.


Vaccines do not contain harmful levels of ingredients. They contain tiny amounts of ingredients such as formaldehyde, mercury and aluminium that make the vaccine safe to store and use. Everyone, including babies, is naturally exposed to higher levels in their environments than they get from vaccines. Our bodies can clear these ingredients without causing harm.

Natural immunity

Vaccination is a safer choice than naturally acquired immunity and can save a child from going through a serious illness.

Natural immunity occurs when you have to fight off an infection. This is sometimes stronger than vaccine-acquired immunity but the risks of this approach far outweigh its benefits.

For example, to develop natural immunity to measles a child would need to catch measles first. However, measles can cause many uncomfortable symptoms and can lead to serious complications, including a one in 500 chance of death. The MMR vaccine is very safe with the chance of a serious allergic reaction less than one in a million.

Vaccines boost your immune system

Vaccination strengthens your immune system by making your body produce antibodies against the disease. This increases your immune response to that disease meaning you're less likely to get it and if you do get it, you're likely to have a less severe version with fewer complications.

Vaccinated children are less likely to get vaccine-preventable diseases and are at no greater risk for other infections.

Multiple vaccines at the same time

The immune system of even very young babies respond to the many bacteria and viruses they come into contact with every day. Having several vaccines at once doesn't overload their immune system. When more than one vaccine is given in one visit, these vaccines have been tested to ensure they are safe and effective to be given at the same time.

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Content shared between HealthInfo Canterbury, KidsHealth and Health Navigator NZ as part of a National Health Content Hub collaborative. Last reviewed June 2021.

See also:

Helping with fear of vaccination


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