Immunisation can protect people against harmful diseases. The Ministry of Health advocates that it is one of the most effective and cost-effective medical interventions to prevent disease.
Immunisation is the process of being vaccinated with a vaccine and becoming immune to the disease.
Vaccination is the administration of a vaccine to produce immunity to a disease.
The National Immunisation Schedule
The National Immunisation Schedule in New Zealand is a series of vaccinations that are offered free to babies, children, adolescents and adults.
Immunisation uses the body’s natural defence, the immune response, to build resistance to specific infections. When an immunised person comes in contact with that disease in the future, their immune system will respond to prevent them developing the disease.
Measles is an example of a highly contagious disease caused by a virus. It begins with a fever, cough, runny nose, loss of appetite and conjunctivitis (pink eye), which lasts for 3–5 days. There may be small white spots inside the mouth. This is followed by a rash that covers most of the body and lasts 4–6 days.
One in three cases of reported measles experience one or more complications. One of these is pneumonia, which accounts for 60% of measles deaths. One in 1,000 people have serious complications including inflammation of the brain. Death occurs in approximately 1–2 per 1,000 reported cases of measles in developed countries such as New Zealand.
Immunisation is the best way to prevent measles. Two doses of measles-containing vaccine are 99% effective in preventing measles.
The MMR (measles, mumps and rubella) vaccine has an excellent safety record. The risk of MMR vaccine causing serious harm is extremely small. Having the MMR vaccine is considerably safer than getting measles, mumps or rubella.
Immunisation is your choice
In New Zealand, parents choose whether or not to vaccinate their children.
Sometimes there are some reactions or side-effects to the vaccines. Common ones are redness and soreness at the site of the injection and mild fever. While more serious reactions to immunisation are very rare, a number of people object to vaccines. Some people worry that the vaccines might contain potentially harmful microorganisms. They may worry about catching the disease or about the vaccine not working or about it having worse side-effects than the disease itself, perhaps even being fatal. Some people object to vaccines on religious or moral grounds. Others are under-immunised through a lack of knowledge and education about immunisation.
The media fuel people’s fears by linking conditions such as allergies, asthma, retardation, autism and Down’s syndrome to vaccines, although there is little to no scientific evidence for most of these claims. Recently, there was an unsubstantiated media claim that the measles, mumps and rubella (MMR) jab caused autism. This affected public opinion (in England and parts of the USA), and a number of people stopped immunising their children. As a result, there was an increase of diseases in those places. The claim was recently disproved in the UK, showing there is no link between MMR and autism.
Vaccines have saved many more lives than they have taken. Of course, testing of vaccines should be rigorous, and public information about the disease, the vaccine and the testing process should be clear and made easily available.
Nature of science
Sometimes work done by scientists is contested by people in the wider community even though it is done to help people. Vaccination is such an issue. While vaccines have saved many lives, there are people who have questions about their safety and some people refuse to be immunised. This is an ethics in science issue where people have to work out what counts as evidence.