The internet is a smorgasbord of fearmongering. Climate change, Ebola, gluten intolerance, skipping leg day… what should we really be afraid of? And to what extent? In this edition of FEAR the highly polarised issue of vaccination gets a rise out of us.
The vertebrate immune system is has two main strategies to fend off infection, namely, the innate immune system and the adaptive immune system. The adaptive immune system allows vertebrates to form immunological memories, discriminate between the body’s own cells (self) and foreign objects (non-self) and orchestrate an effective response to rid the body of pathogens (viruses, bacteria, protozoa etc.) that have the potential to cause harm. HOLD IT… why are we explaining pathogens when bored teachers with autotune is a thing?
Anyway… despite coming in various forms (see table below or this video), vaccines generally achieve their goal using the following mechanism, which we’ve massively oversimplified for the sake of brevity:
- The vaccine is introduced to the body, usually via an injection, but sometimes orally.
- The immune system responds and learns how to fight off the pathogen.
- Information on how to fight the pathogen is retained by specialised cells, such as B lymphocytes and T lymphocytes.
|Live Attenuated||Live but weakened pathogens.||Measles, Mumps and Rubella (MMR) … more on this later.||Induces a strong and long lasting immune response.||Possibility (very small) that the vaccine will revert to its wild type and cause disease.|
|Inactive||“Dead” pathogens.||Typhoid (injection)||If it’s dead it can’t reproduce and cause disease.||Not always effective long-term, boosters are required.|
|Antigen (Subunit)||Antigens, which are the parts of the pathogen that stimulate an immune response.||Hepatitis B||Does not introduce viral particles.||Provokes a weaker immunological response than the whole pathogen would.|
|Virus-Like Particle||Broken up viruses with the nucleic acids (DNA or RNA) removed.||Influenza||The particles can self-assemble into a shape resembling the original virus, but contains no nucleic acid (DNA or RNA), so it doesn’t reproduce.||Getting the particles to self-assemble correctly is a challenge.|
|Toxoid||The toxin produced by the bacteria.||Tetanus||Highly effective at blocking harmful toxins.||Does not actually help the immune system deal with the pathogen.|
By inventing vaccines, rather than continuing to tackle the disease mano a mano as nature intended, it would appear humans have learnt how to trick the adaptive immune system giving us something for nothing. If you count getting stabbed in the arm with a needle nothing. FYI we don’t, but we’ve got used to our smallpox free lifestyles.
So, the time has come to address the elephant in the room. There is a lot of controversy over vaccination and the internet is one hell of a breeding ground for it. That said, the controversy dates back about as far as vaccination itself, the old timey propaganda images are evidence of that (see below).
On the face of it, issues tend to be separated into two types, efficacy and safety. Turning first to efficacy, since the introduction of vaccines the prevalence of diseases has dropped massively (see infographic below), smallpox has been eradicated and efforts to eradicate other pathogens are well underway. The obvious counter argument made by anti-vax campaigners is that correlation does not imply causality. So far, so good.
Anti-vax campaigners argue that improvements in hygiene and sanitation since the introduction of vaccines are the real reasons for the reduction in disease, but this is where their science is flimsy. Certainly, better hygiene and sanitation can massively reduce the incidence of disease, but even in a highly sanitary environment pathogens would still be around and people will still get infected, so you would expect serious but localised outbreaks of disease to occur every so often. The fact that this doesn’t happen in the developed world indicates that this theory is incorrect. Further to this, developing nations, which may lag behind in terms of sanitation, have also seen a fall in disease, efforts to eradicate polio in India are a testament to this.
What actually happens is that vaccines prime our immune system so that the infection is stopped before it causes damage i.e. becomes a disease (see graph above) and spreads, thus preventing us from suffering disease symptoms and the scientifically named “sad times”. If a large enough percentage of the population is vaccinated then the pathogen cannot jump from one susceptible person to the other and the whole population is safe. This called herd immunity and it allows us to protect those who cannot be vaccinated for legitimate medical reasons, such as old age or immunodeficiency. This is how, in combination with improved sanitation, hygiene and education, vaccination can aid the total eradication of diseases.
In terms of safety there have been many reviews, but this one, from a respected scientific journal (the fact that we even have to say this tells you how much pseudoscience there is to wade through) is a good example of a systematic analysis of the evidence.
The review claims that as the success of immunization increases the safety concerns also increase, because if the prevalence of the disease reduces, people are less worried about disease and become more occupied with adverse effects of the cure. This seems like vaccines could be considered a victim of their own success, but that would gloss over the failures of those charged with maintaining the confidence of the public. However, maintaining public confidence is tricky and the reviewers have recognised a consistent pattern in how vaccines get blamed for stuff:
- Cases of a medical condition increase or new medical condition arises.
- Someone cries foul and blames vaccines (the correlation is not causality argument disappears when it suits them).
- Investigations with poor methodology confirm their suspicion.
- Investigators tell the public, often before/without sufficient peer review.
- The results resonate with those who suffer with the condition and public confidence is lost.
- The results are found to be incorrect and the fear unfounded.
- Regaining the confidence of the public takes longer than it did to lose.
A good example of this is the MMR vaccine. In 1998 former doctor Andrew Wakefield falsified data to suggest a link between the MMR vaccine and autism. This destroyed public confidence in the safety of the vaccine (see graph below) and over 15 years later uptake of the MMR vaccine in England has finally rebounded but remains below the World Health Organisation’s target of 95%.
Provided that the pharmaceutical industry doesn’t suddenly become extremely lax with their safety testing, the real danger to the population is those who do not get vaccinated. When more and more people refuse vaccination, herd immunity is compromised and you get outbreaks of preventable disease, just like the measles outbreaks in the USA in recent years.
Unfortunately, once people have hold of an idea they tend to find it difficult to let go and research suggests that such is the case with vaccines. Moreover, the methods of hardcore anti-vax campaigners don’t seem to change with time or evidence. Essentially, having ignored the evidence they’ve become charlatans, peddling mistruths and propaganda.
One such charlatan is Jenny McCarthy, leader of Generation Rescue, a group who still incorrectly promote the link between vaccines and autism. McCarthy a former co-star of Charlie Sheen, displayed her lack of medical expertise quite recently when Sheen announced that he is living with HIV.
Generation Rescue campaign heavily against a mercury based vaccine preservative called thiomersal, which has been scientifically established as safe in the volumes used in vaccines. McCarthy’s former partner Jim Carrey, has also been vocal on the subject (yeah, we were heartbroken too), earlier this year he posted a picture of an autistic boy along with a rant about vaccines on twitter. Needless to say the boy’s family weren’t happy and he ended up having to apologise (below).
This is just the thin end of the wedge, as the evidence gets weaker, the fearmongering gets stronger and as Godwin’s law dictates, eventually someone will invoke the Nazis. That makes this a good place to stop.
In conclusion, it is patently obvious, to all who have considered the evidence, that the vast majority of arguments against vaccination are fundamentally flawed and often just made up, but that’s indicative of the problem. Not everyone has considered all the evidence and it is counter-productive to climb upon a high horse and tar all those who don’t vaccinate their kids with the same brush as a minority who pump the internet full of “toxic” (see what we did there) propaganda. Fundamentally, these are people who are concerned for the wellbeing of their kids, but were misled by charlatans. The only way to overcome this is through greater education about vaccination specifically and promotion of science and evidence-based critical thinking in general. Unfortunately, we live in a world where it’s easier to constantly fear monger than constantly educate and falsehoods are easily sown, but difficult to root out.
Fear Rating: 1/10 – The needles are sharp, but don’t be afraid of pricks.