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Vaccines
How do they work? What types are there? Are they effective?
Key points about vaccines
Vaccinations are one of the best ways to protect against many serious infectious diseases.
Routine immunisation programmes protect most of the world’s children from a number of infectious diseases that previously caused millions of deaths each year.
Read about how vaccines work, the different types of vaccines and how effective they are.
If you’re concerned about immunisation, knowing the facts can help you feel more confident about getting vaccinations for you and your whānau. In the following videos, Dr Keriana Bird discusses commonly asked questions about immunisation. Knowing the facts can help you feel more confident about making sure your child has all their vaccinations.
Immunisation:
is one of the best ways to protect your child against the risk of serious diseases.
involves receiving a vaccine to help your body's immune system protect you against a disease.
is also known as vaccination.
Video: Why immunise?
(Ministry of Health, 2019)
Video: An informed choice
(Ministry of Health, 2019)
Video: Worldwide protection
(Ministry of Health, 2019)
To understand how vaccines work it helps to understand how your immune system works. Your body has a natural defence system called the immune system which helps fight off germs that can cause serious disease by making antibodies.
Being vaccinated causes your body to produce antibodies. This means that if you're infected with a disease (from a cough, sneeze, blood, etc), 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, recover faster and are less likely to have serious complications.
Babies are born with immunity to some infections because their mother’s antibodies are passed on to them in the womb, but this immunity doesn't 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. Read more about vaccine-preventable diseases.
In the video below Dr Kiri Bird explains how our immune system works and how getting vaccinated helps protect the whole community.
These contain bacteria or viruses that have been weakened so that they can't cause disease.
After vaccination, the weakened vaccine viruses or bacteria replicate (grow) in the vaccinated person.
This small amount of virus or bacteria can stimulate an immune response.
Live vaccines are not recommended if you are pregnant or have a very weak immune system from active cancer, leukaemia, lymphoma, HIV or are taking medicines that can weaken your immune system.
These contain bacteria or viruses that have been killed or inactivated.
They can be safely given to a person with a weakened immune system. However, you may not develop the same amount of protection after vaccination as a healthy person receiving the vaccine.
With inactivated vaccines, you usually need many doses to give full protection against diseases.
Subunit vaccines
These contain parts of bacteria or viruses or bacterial toxins that have been made harmless.
This vaccine does not contain any virus. Instead, it contains a molecule called mRNA that has instructions for making the spike protein on the surface of the COVID virus. The virus needs this spike protein to enter your body’s cells.
The mRNA from the vaccine does not stay in your body, but is broken down shortly after vaccination.
Vaccines may also contain other ingredients, such as preservatives, and ingredients that help your body respond to the vaccine. The very small amount of these ingredients does not cause any harm. Learn more about what ingredients are in a vaccine.
Studies have shown that if all recommended doses of vaccines are given, they will protect 80–98% of the children who are vaccinated. For example, pertussis (whooping cough) vaccine is effective in about 84% of children and the measles vaccine in 90–98% of children.
Vaccination is an important part of protecting the community against disease. This helps to prevent serious infections spreading 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 don't 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 to stay protected.
Video: I've heard some people still get sick. Does that mean immunisation doesn't always work?
(Ministry of Health, 2019)
When to get immunised
The National Immunisation Schedule(external link) has a list of free vaccinations for different ages. Most vaccines are given when we are babies and children to build up immunity. Vaccination starts at 6 weeks old.
Vaccinating on time gives the best protection. Missing or late vaccinations can put your family/whānau’s health at risk.
Image credit: Health New Zealand | Te Whatu Ora
Other vaccines are recommended for people who are at greater risk of certain diseases, such as people with a weakened immune system because of illness or the medicines they are taking, the elderly or people who are travelling overseas where certain diseases are more common.
Funded and unfunded vaccines can be given by your doctor, nurse, midwife and some paramedics and pharmacists who have been trained as vaccinators.
Different providers may have restrictions on what vaccinations can be given or the ages of people they can administer these to. So it’s worth checking with the provider first to see if you or your whānau can get the vaccination needed from them.
There are many different settings in which you can get a vaccination. These include medical or health centres, pharmacies, community-based clinics including marae-based clinics, mobile health clinics and mobile vaccination services.
