Te āhua o te mahi o ngā rongoā āraimate How vaccines work

All vaccines are free if you are eligible.

Diseases can be caused by viruses and bacteria. These are so small that you cannot see them, but they are everywhere. Most are harmless, but some can make you really sick.

Inside your body, your immune system helps fight against diseases caused by viruses and bacteria. Sometimes, your immune system needs a little help. Vaccines give your immune system instructions on how to defend itself better so your body will have the right tools for the job, meaning you are less likely to get sick.

To be fully protected you usually need more than 1 dose of a vaccine.

When you are first vaccinated, your body learns what to do if it meets a particular virus or bacteria. Your second (and sometimes third or fourth) dose boost your immune system so you will have stronger, and longer-lasting, protection.

Different vaccines protect you for different lengths of time, which is why you may need a booster vaccination to strengthen your immunity.

Before any vaccine is approved for use, it goes through a long and rigorous testing process by scientists around the world and in Aotearoa New Zealand to ensure its safety and effectiveness.

This process can take several years and compares the health of people who have been immunised with those who have not.

Once approved, the safety of the vaccine is also continuously monitored by Medsafe. As part of this process, the Centre for Adverse Reactions Monitoring at Otago University records reactions reported after vaccinations so that scientists can keep track of any reactions that may occur.

Vaccine side effects, reactions, and safety