When a high percentage of people are vaccinated, there are too few susceptible people left to infect.
Science is the field of study concerned with discovering by observing and experimenting.
Although anybody can do science, professional scientific researchers follow a scientific method which allows them to explain occurrences using a logical, consistent, systematic method of investigation.
This involves collecting large amounts of data from well thought out experiments and analysing that data to arrive at a well-tested, well documented, theory that is supported by the evidence.
The theory is then subjected to critique by other experts and only if approved by them is it allowed to be published in a peer reviewed journal for others to read and learn from.
As a person who reads and writes peer reviewed journal articles, I’ll admit that they can be difficult to understand, are often filled with specialist jargon, and are not usually available to the public without having to pay a fee.
This makes obtaining and analysing scientific data difficult and expensive.
What is easy to obtain and analyse is scientific information from websites and documentaries which are deliberately designed to be simple to understand, easy to access and contain memorable, shareable sound bites.
Websites, social media posts and documentaries however do not have to follow any of the rules of peer reviewed scientific method, and instead can make incredible ‘scientific’ claims based on anecdotal stories beautifully packaged into believable emotive narratives.
I mention this as the controversial anti-vaccination film Vaxxed: From Cover-Up to Catastrophe is touring New Zealand.
The movie, directed by Andrew Wakefield the former British doctor who was struck off the medical register over an unethical study, claims to give the other side to the vaccination argument.
Let’s be clear – the whole point of peer reviewed scientific method is that there is no other side.
Science presents all sides, that’s the beauty of science, it’s transparent and open about its evidence based conclusions.
Experiments carried out over hundreds of studies by scientists all over the world involving more than 15 million children conclude clearly that vaccines are not linked to autism.
For those that don’t want to trawl through all of the peer reviewed scientific studies that have shown this, the Cochrane systematic review of research on the MMR vaccine gives a great public summary.
In light of this, there are still hundreds of websites claiming that vaccinations are dangerous, an issue emphasised this week at Grantlea Downs School in Timaru.
The school’s board of trustees, of which I couldn’t find out how many were familiar with scientific method, decided not to allow their students to receive the free vaccine against Human Papilloma Virus (HPV) on site.
The vaccine is highly effective in preventing infection HPV responsible for about 90 per cent of HPV caused cancers, and school-based vaccinations programmes are the most convenient way for children to get protected against HPV.
Convenient vaccination programmes are important because they work on herd immunity, a form of immunity that occurs when the vaccination of a significant portion of a population provides protection for individuals who have not developed immunity due to being too young or too ill to be vaccinated.
When a high percentage of the population is protected, there are too few susceptible people left to infect and diseases become difficult to spread.
Anti-immunisation websites and movies create fear with cherry-picked science and reductions in childhood vaccinations will allow disease transmission chains to rebuild meaning herd immunity will no longer be effective.
I’m all about freedom of choice, but if you are going to put other people at risk, you should have a really good reason. A movie or website isn’t one of them.
Dr Michelle Dickinson, also known as Nanogirl, is an Auckland University nanotechnologist who is passionate about getting Kiwis hooked on science.