Common questions about vaccines and vaccination

Safety and risks

Fact: Vaccines are very safe. Watch the video below to learn more about how vaccines are approved for use so we can trust they're safe to use.

Video: Vaccine safety

In the video below Dr Keriana Bird, a GP, helps answer the question of whether vaccines are safe.

(Ministry of Health, NZ, 2017)

Side effects

Most reactions from vaccines are an expected sign that your immune response is building. Most reactions are temporary and minor, eg, a mild fever or sore arm. These reactions show that the vaccine is working because your immune system is responding.

Vaccines prevent you from serious illness from disease. For some people, especially children, these illnesses can be fatal. This is far worse than a reaction you may have after a vaccine. So the benefits of being immunised against a disease by a vaccine greatly outweigh the risks, and without vaccines many more disabilities and deaths would occur. 

It's rare to have a serious reaction following a vaccination. Anaphylaxis is a serious allergic reaction to a vaccine or 1 of it’s ingredients and happens soon after the injection has been given. This is the reason why you must wait at the doctor's clinic for 20 minutes after vaccination. Read more about medicines and side effects and reporting a reaction that you think might be a side effect.

Video: Louis's 15 month immunisations

(Health New Zealand | Te Whatu Ora, NZ, 2023)

Video: Are there any side effects from vaccines?

In the video below Dr Keriana Bird, a GP, helps answer the question about side effects of vaccines.

(Ministry of Health, NZ, 2019)

Fact: It’s impossible to get the disease from any vaccine that's made with dead (killed) bacteria or viruses or made from just part of the bacteria or virus.

The few vaccines in Aotearoa New Zealand that contain live organisms may cause some people to develop a very mild form of the disease with a rash and a fever. The risk of disease from vaccination is very small and much less severe than if you became infected with the disease-causing organism itself.

Vaccines only contain killed bacteria or viruses or a part of the bacteria or virus, or a much weaker form that is just enough to stimulate your immune system without causing the disease or putting you at risk of complications from the disease.

Fact: Vaccines don't contain harmful amounts of ingredients. Vaccines contain ingredients that allow them to be safely given to you. The ingredients in vaccines are at a lower level than what we are naturally exposed to in our environment. This means they don't cause harm as part of a vaccine.

Video: What ingredients are in a vaccine?

In the video below Dr Keriana Bird, a GP, helps answer the question of what's in a vaccine.

(Ministry of Health, NZ, 2019)

Fact: Natural immunity occurs when you've been infected with a bacteria or virus and have created antibodies to it. Vaccination is a safer choice than naturally acquired immunity and can save you or a child from having to go through the serious illness or complications from having a serious illness.

It's true that natural immunity may sometimes be stronger than immunisation through having a vaccination, but the risks of getting infected with the disease far outweighs the small difference in benefit.

Some vaccines actually provide you with better immunity than natural immunity. For example, to develop natural immunity to measles, a child would need to catch measles first. Measles can cause serious symptoms and complications, including death. About 1 in 20 children with measles develop pneumonia, and a quarter (5 in 20) need to stay in a hospital. Measles complications can lead to serious long–term disability. The World Health Organization (WHO) states that in the years 2000 to 2022, vaccinations contributed to preventing 57 million measles–related deaths. 

By getting immunised with a vaccine there's a much lower risk of harm from measles. It's extremely rare that someone reacts severely to the vaccine and the vaccine’s effect likely lasts for your whole life. 

Video: Is there a natural alternative to immunisation?

In the video below Dr Keriana Bird, a GP, helps answer the question of whether there's an alternative to immunisation.

(Ministry of Health, NZ, 2019)

Fact: Vaccine-preventable disease rates have dropped because vaccination is now common around the world.

In recent years, however, the number of people getting some of these diseases has increased. There are still epidemics or outbreaks of some diseases in Aotearoa New Zealand including:

• whooping cough (pertussis)
• measles
• mumps.

Research has found that children who don't get vaccinated are contributing to this trend, the fewer people who are vaccinated, the more likely the disease can spread. 

To prevent the spread and return of several diseases, it's important that children continue to receive vaccinations.

Video: A lot of these diseases aren’t around anymore. Do we still need to worry?

In the video below Dr Keriana Bird, a GP, helps answer the question of whether we still need to immunise against diseases that aren't around anymore.

(Ministry of Health, NZ, 2019)

Fact: Vaccination strengthens your immune system because it makes your body produce antibodies that can recognise and fight disease if you're exposed to it later.

There's a lot of research that shows that vaccinated children are healthier and have better health outcomes. They're less likely to get vaccine-preventable diseases and aren’t at any greater risk for other infections.

Fact: Vaccines don’t cause autism. In 1998 a British doctor thought there was a link between the measles, mumps and rubella (MMR) vaccine and autism. The doctor had changed patient data and the laboratory reports were incorrect. The study was removed from the scientific literature and the British authorities removed the doctor’s license to practice medicine.

There are now many large, well-conducted studies that have looked at this issue. They all show strong evidence of no connection between autism and the MMR vaccine; the MMR vaccine is very safe.

Fact: The immune system of even very young babies can respond to many vaccines at the same time. Children are often the most vulnerable to these diseases, so if vaccines are spread out over a longer time, there's a chance of missing the best time to protect our tamariki.  

Aotearoa New Zealand’s immunisation schedule is based on many years of medical evidence showing the best time for vaccines to be most effective in preventing  disease.

Fact: Herd immunity only happens when very high numbers of people in each area get vaccinated.

For very infectious diseases, the percentage of the community that needs to be immunised needs to be higher to protect those that haven’t been vaccinated. If several people in your community aren't vaccinated, your child is at risk of catching disease. 

Herd immunity doesn’t protect against all vaccine-preventable diseases. An example is tetanus, which is caught from bacteria in the environment and not from other people. So it doesn’t matter how many people around you are vaccinated against tetanus, it won’t protect you from tetanus. Vaccination to provide protection for each person is vital.

Even where there's a high rate of vaccination, herd immunity offers no guarantees. The protective effect of herd immunity can vary based on the 'herd' that you move among. Travel or moving to a new country or area, even a new circle of friends can change who’s in your herd and therefore the chance you can have shared protection against infection.

Measles is very contagious. Recent epidemics of measles in Aotearoa New Zealand and overseas have happened because there were low rates of vaccination in some age groups and other people relied on herd immunity so didn't get vaccinated themselves. The result of this is that many children have become very ill and some have died. 

Read more about herd immunity.

Fact: The Pfizer vaccine can be given at the same time as any other vaccine on the National Immunisation Schedule(external link) or the influenza vaccine. If you're given 2 vaccines at the same time, you'll receive the vaccines in separate places on your body (eg, different arms) and with different syringes. Read more about the Pfizer COVID-19 vaccine and the flu vaccine.