Print this topic

HealthInfo Aoraki South Canterbury

Overview of vaccination

Getting vaccinated is one of the best ways to protect yourself against many serious diseases.

Antibodies are an important part of your body's immune system. Antibodies are proteins your body makes to fight off infections.

Vaccines work by causing your body to produce antibodies against a particular disease. This means that if you are infected with that disease (for example, from a cough, sneeze or blood), these protective antibodies are already in your bloodstream to quickly fight off the germs. Even if vaccinated people do get sick from the disease, they usually get a mild form of that disease – and recover faster and are less likely to have serious complications.

Babies are born with immunity to some infections because their mothers' antibodies are passed on to them in the womb, but this immunity does not last long. Babies get more immunity from being breastfed and, as they grow, they need vaccinations at specific ages to protect them from many life-threatening diseases.

Vaccine-preventable disease rates have dropped because vaccination is now a widespread and common practice. To prevent the spread (and return) of these diseases, it's vital that children continue to receive vaccinations.

Types of vaccines

Vaccines may also contain other ingredients, such as preservatives and ingredients that help your body respond to the vaccine. The very small amounts of these ingredients do not cause any harm. Learn more about what ingredients are in a vaccine.

Level of protection

Studies have shown that if all recommended doses of vaccines are given, they will protect 80 to 98% (80 to 98 out of every 100) children who are vaccinated. For example, whooping cough (pertussis) vaccine is effective in about 84% of children and the measles vaccine in 90 to 98% of children.

Vaccination is an important part of protecting the community against disease. It helps to lower the spread of serious infections and protects babies who are yet to be fully vaccinated and people who cannot be vaccinated because they are unwell. About 95% of people in the community need to be vaccinated to protect the whole community against diseases like measles.

A very small number of people who are vaccinated do not develop strong immunity and they may still become ill with one of the diseases. If that happens, they usually have a milder illness than people who have not been vaccinated.

More than one dose of some vaccines is needed for full protection. Booster doses of vaccines may be also be needed for some diseases.

Side effects

Most reactions to vaccines are mild, such as fever or redness at the injection site. These reactions show that the immune response is building and the vaccine is working. Very rarely, a serious allergic reaction (anaphylaxis) can happen. This is treatable and occurs soon after the injection. This is why you must wait at the doctor's clinic for 20 minutes after your vaccination. If you are worried, contact your doctor straight away.


The approved vaccines used in New Zealand are very safe. The following page has more detail about vaccine safety.

  HealthInfo recommends the following pages

On the next page: Vaccination safety

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


See also:

Helping with fear of vaccination

Page reference: 881874

Review key: HIIMM-47872