By Martin McHugh, University of Limerick; Aimee Stapleton, University of Limerick; Anne Marie Healy, Trinity College Dublin and Sarah Hayes, University of Limerick

Opinion: long before social media, vaccination controversies have demonstrated the power of fake news

When the Smallpox vaccine was originally created in the late 18th century, it was met with hostile opposition from medical practitioners called "variolators". Variolators would take Smallpox scabs or fluids and insert them into or rub them on artificial scratches on the patient's skin. A similar technique had been used for hundreds of years in Asia, in which powdered Smallpox scabs were blown into the nasal cavity. What resulted would be a less severe Smallpox infection that lasted between two and four weeks with a one to two percent chance of death, as opposed to between 30% and 80% chances from normal infection. In the vast majority of cases, the patient retained immunity from the disease once recovered.

With the introduction of vaccines, variolators soon realised their ability to make a living was in jeopardy. They fought the introduction of vaccines in any way they could and essentially were the first "anti-vaxxers" with their publications depicting the vaccine causing cow-like mutations leading to death. It is estimated that Smallpox has killed between 300 and 500 million people. It was eradicated in 1979 because of vaccination. 

From RTÉ Radio 1's Drivetime, Myles Dungan's On This Day essay on the history and impact in Ireland of smallpox, one of the most dreaded diseases of the 18th and 19th centuries

The most infamous vaccination controversy of all occurred in 1998 when The Lancet, medicine's oldest and most prestigious research journal, published a research article suggesting a causal link between MMR, the combined measles, mumps and rubella vaccine, and the development of autism in children. What ensued was a media frenzy, the effects of which are still being felt today.  At the time, this news was very real. But what was unknown to the general public and news outlets was that the study was grounded in poor scientific practice and serious conflicts of interest, which The Lancet failed to weed out prior to publication.

In the publication, 12 children with regressive developmental disorders were described. In eight of the 12 cases, either the parent or respective paediatrician believed that the MMR vaccine was the causal factor behind the patient’s autism or autism spectrum disorder (ASD). The hypothesis presented was that the vaccine caused gastrointestinal inflammation which led to usually non-permeable peptides entering the bloodstream. These peptides were then thought to have caused neurological damage in the form of autism.

The results of the article have never been replicated and no link between the MMR vaccine and autism has ever been established. In light of this, proponents of the hypothesis that there was a link between the MMR vaccine and autism suggested that a mercury-containing preservative used in vaccines at the time called Thimerosal was the cause of neurological damage. No scientific evidence has been generated to support this claim, which has been refuted by multiple research studies.

From RTÉ One's Six One News, Kate Egan reports a disciplinary panel in London has ruled that Dr Andrew Wakefield abused his position of trust as a medical practitioner

Through multiple inquiries, it emerged that the primary author of the original Lancet article, Andrew Wakefield, falsified data to support his original claims. Since 1998, many of the original co-authors have retracted their names from the publication. In 2010, The Lancet retracted the paper and, three months later, Wakefield was banned from practicing medicine due to severe malpractice.

The two largest medical breakthroughs of all time are sterilisation and vaccination. Combined, they have saved more lives than any other human endeavour.

A foreign entity that causes illness upon entering the body is known as an antigen. Antigens take many forms, but common ones are bacteria or viruses. Upon entering the body, they multiply and can cause serious distress and even death in many cases. When an antigen enters the body, our immune system produces a protein called an antibody. Antibodies work to eliminate the antigen and protect against the infection spreading.

From RTÉ Radio 1's Drivetime, Cork-based GP Dr Nuala O'Connor and Fianna Fáil spokesman on Primary Care and Community Health John Brassil discuss the rising number of cases of meningitis and septicaemia and the call for the Meningitis B vaccine to be rolled out for free to all children

The human body is very efficient at producing antibodies but, often when our immune system is exposed to a new antigen, it can be several days before it produces the correct response. This is the case for diseases such as measles or whooping cough that can prove deadly in the time our body figures out a defensive response.

Vaccines essentially train your body to stave off specific diseases. Vaccination introduces a weakened or dead antigen and its surface proteins or toxins to the body to stimulate the immune system to replicate the same response it would if you contracted a disease. In this state, the antigens cannot cause an infection, but the body recognises the antigen and works to create antibodies. This is vital because the next time you encounter the same antigen, (say, mumps), your immune system immediately knows how to disarm the threat. 

Not only is vaccination beneficial to the individual, it also benefits the population as a whole. When a large percentage of the population is vaccinated, a new form of protection called "herd immunity" develops. This is vital, as certain cohorts within any given population cannot be vaccinated. Imagine if you were undergoing chemotherapy.  Because your immune system is compromised, you cannot receive vaccinations. You are now are solely reliant on herd immunity, the fact that everyone else is disease free, for protection.

From RTÉ Archives, RTÉ News report by George Devlin on the dramatic fall in measles since the start of an immunisation campaign in 1986

Herd immunity means that the odds of a pathogen spreading is highly reduced because the likelihood of multiple unvaccinated individuals being in contact is low. This makes it difficult for a chain of infection to begin, as a vaccinated person is unaffected by the disease. Herd immunity provides indirect protection, as you are reliant on others, but is vital for young children and those with weak immune systems.

In various times throughout history, vaccination has been mandatory and refusal has been punishable with hefty prison sentences, torture and public humiliations. At present, vaccination is highly recommended in Europe, but is essentially a choice, one that many people are now refusing.

In some ways, vaccines are a victim of their own success because we don’t see the horrendous impact of infectious disease anymore, though this may change. In 2016, cases of measles across Europe stood at 5,273 and this rose significantly in 2017 to 21,315. The same pattern is being repeated all over the world with multiple infectious diseases. Those who are unvaccinated run the risk of infection, but also create higher rates of infection for others by drastically lowering the effectiveness of herd immunity.

From RTÉ One's Prime Time, director of the Health Protection Surveillance Centre, Dr Kevin Kelleher on the huge rise in mumps cases in the first six weeks of 2019

The recent outbreak of measles in Co. Donegal drives home the message that serious diseases can re-emerge when enough members of the population are unvaccinated. While the rates of vaccination in Ireland are high, the number have been dropping slightly over the last few years, weakening our herd-immunity. This is a worrying trend that needs to be fixed before more people become infected. At this point, the HSE has confirmed two cases of measles in Donegal and reported a further three probable cases.

History has stood, and will continue to stand, on the side of vaccination. Vaccination saves lives. The scientific evidence supporting this fact is rigorous and robust. Armed with this knowledge, people should make the informed choice to vaccinate.

Dr Martin McHugh is an Education and Public Engagement Officer at the Synthesis and Solid State Pharmaceutical Centre (SSPC), the SFI Pharmaceutical Research Centre, at the University of LimerickDr Aimee Stapleton is an Education and Public Engagement Officer at SSPC at the University of LimerickProf Anne Marie Healy is a Principal Investigator in the SSPC and is based in the School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin. Dr Sarah Hayes is the Education, Outreach and Training Officer at the SSPC at the University of Limerick

The views expressed here are those of the author and do not represent or reflect the views of RTÉ