Issues in Interdisciplinarity 2020-21/Evidence in the fight against anti-vaccine movements

Introduction
Despite the common impression that anti-vaccination movements emerged through the Internet, they arose as soon as vaccination started being popularised. The vaccine against smallpox in the 1800s faced immediate hostility, seen as ‘unchristian’ and a violation of people’s personal liberty. Although the ways of expressing and spreading this opposition have evolved, the motives behind it today are still the same, opposing public health and medicine to civil liberty and choice.

Biology
Biological evidence promotes vaccination: the larger the vaccinated population, the better.

Yellow Fever
Yellow Fever is a disease prevalent in Africa that can be fatal, involving kidney deterioration and jaundice. It does not have any specific treatment and is responsible for 30,000 deaths every year, with a of 50% or higher in severe cases. Being spread by mosquitoes, it cannot be eradicated, hence the importance of vaccination to reduce the number of its victims. Research has shown that the 17D (YF-17D) vaccine is efficient after 10 days in 95% of the patients, lasting for up to 30-35 years. Although the recommends a single vaccination, study has shown that its efficiency is limited (with only 50.4% of Malian children still seropositive after 3-5 years), suggesting a second administration is required to reach an 80% immunity of the population, preventing yellow fever outbreaks.

Some evidence in the biological domain however shows harmful effects of the vaccine. Several pathologies have been linked to this vaccination, such as transverse myelitis, encephalitis , and peripheral facial paralysis. Nevertheless, the vaccine remains the most efficient way to prevent yellow fever and its adverse effects are very low, going from 0.4 to 0.8 cases per 100 000 vaccines.

Vaccine efficacy
Vaccine efficacy is calculated according to the difference between vaccinated and unvaccinated people who catch a disease. According to the Centres for Disease Control and Prevention, is 90% effective against polio for two doses (99-100% for three doses), making the US polio-free since 1979, the vaccine against chickenpox is 90% effective (two doses), and  vaccine is about 93% effective for one dose (97% for two doses) at preventing measles, leading to a 99% reduction of cases in the US.

Biological quantitative evidence therefore largely promotes (compulsory) vaccination, as the vaccines administered often have very high efficacy rates and help stop the spread of (or even eradicate) diseases. The few biological evidence used by the anti-vaccine movements often aims to show the causality between certain vaccines and diseases or infant deaths. However this evidence is often flawed or irrelevant statistically, compared to the number of lives saved by vaccination – preventing 2 to 3 million deaths every year - raising nevertheless ethical questions about the 'collateral damage' of vaccination.

Ethics
Ethics focus mainly on qualitative evidence concerning people's freedom and safety, presenting arguments that tend to support optional vaccination.

Philosophy
Philosophy in Ethics prompts reflection on what can and cannot be done, representing anti-vaccination movements' main focus. Their concerns oppose utilitarianism and consequentialism, highlighting the risks of vaccination for individuals rather than the overall population's safety. The example of Andrew Wakefield and the Lancet MMR autism fraud illustrates this. His study in the ’90s falsely stated that autism was a side effect of the MMR vaccine, resulting in an epidemic of rubella in the USA, showing the dangers of anti-vaccination movements, harming the population's health. Furthermore, anti-vaccine activists question the government’s right to force an individual's vaccination to attain herd immunity, despite refusal, leading to cases like Henning Jacobson's trial in the 20th century. Anti-vaxxers perceive vaccination as an invasion of autonomy and freedom, especially of children's rights, asking when a parent’s objection can be overcome.

Religion
Religion is another central matter in Ethics, the freedom of belief being a fundamental right. Vaccines were long seen as evil, being considered « unnatural ». Christianism for instance rejects vaccines containing embryonic origins derived from aborted foetuses, considered morally incompatible. Islam on the other hand, is opposed to certain vaccines that contain traces of pork gelatine, not being halal. Those reasons are hard to overcome in movements to fight anti-vaccination as they are more than evidence but beliefs.

Internet and Social Media
Finally, Ethics are involved in the role of the Internet and social media, which represents an increasing threat for vaccination. 43% of websites on Google associated to the key words « vaccination » or « immunisation » are led by anti-vaccination movements  supported by accounts like « Beware the Needle » on Youtube or Instagram, spreading fake news that feed conspiracy theories. These websites represent dangerous content within anyone's reach, discrediting vaccination and governments' intentions, failing their ethical responsibility to inform, in addition to endangering the population.

Public Health
Public health as a discipline is the science of promoting the population’s health as a whole. It plays a crucial role in solving tensions in the evidence proposed in various disciplines, but also within them. Overall, public health professionals try to fight the anti-vaccine movement.

Compulsory vaccines
Governments can enforce mandatory vaccines to avoid the resurgence of a disease by promoting herd immunity, based on evidence relying on principles commonly used in Public Health. The “harm principle”, developed by John Stuart Mill, declares that unvaccinated people could be a danger to society as spreaders of the disease. Additionally, the “precautionary principle” states that preventive measures must be taken when a country is threatened by a virus. These principles apply utilitarianism, prioritising the well-being of the majority rather than the individual's. Hence, evidence in biostatistics, showing that punctual negative effects are negligible in front of the overall success of vaccines, mirrors public health’s goal of assuring the population’s safety (sometimes at the expense of the individual's).

However, vaccine exemptions for medical, religious, and philosophical reasons exist, based on the right of the individual's choice, although their validity varies widely. In the United States, 43 states allow religious exemptions, while only 15 allow philosophic exemptions. Overall, public health does not consider much personal choice – which is one of the arguments used by anti-vaccination movements –, and some countries like the US seek to consider ethics more by imposing less compulsory vaccines.

Education
In the fight against anti-vaxxers, education plays a crucial role. Today 70% of parents go to the internet to educate themselves on vaccination, but the overwhelming amount of misinformation leads to a confused population, often deprived of valid evidence. To educate families, trained healthcare providers remind the dangers of certain diseases and explain herd immunity as well as the process of vaccines' commercialisation. Online education campaigns have also proved to be efficient, with 66% of parents and 88% of pregnant women raising awareness and checking up on their children’s vaccination after having seen such campaigns in Australia. These strategies reduce interdisciplinary conflicts, simply by educating people instead of depriving them from their free will.

Conclusion
Altogether, the fight against the anti-vaccination movement is far from finished, due to contradictory evidence between disciplines. Today, as the Covid-19 vaccines are facing “vaccine hesitancy” and misinformation, it is necessary for Public Health to gain the trust of the population in order to reach enough vaccination coverage.