The Vaccine Blog

Why and when is anti vaccine activism the most harmful

Why and when is anti vaccine activism  the most harmful?


  • Introduction


This is probably one of the most timely topics I've written about. We`re entering Year 5 of the COVID-19 pandemic. Further, outbreaks of measles and other diseases of the past are being reported by health authorities like the CDC and WHO across different US states seemingly every other week. 


The first thing I`ll say is that I`m not referring to hesitancy, queries or concerns. It`is well established that vaccine hesitancy is a spectrum (read more about this here). It ranges from complete acceptance of all vaccines at one end of the spectrum. Those in the middle of the spectrum may delay or reject some or all vaccines. On the other end of the spectrum, it can involve  complete rejection of some or even all vaccines. Regardless of where on the spectrum any individual lies, vaccine hesitancy  varies with time, place, and vaccine. Also, across the literature, the 3 major determinants are complacency, convenience and confidence. This is true whether the vaccine or vaccines in question are routine or new. 


In previous posts, I've discussed the lower extremities of this spectrum; that is those who are completely receptive to all vaccines, and those who may delay or reject some or all vaccines. However,in this post, I'm referring to the opposite extremity. The vaccine-resistant, or the true “anti-vaxxers”. I`m referring to those who deliberately disseminate  inaccurate information, or more blatant disinformation. I`ve written about disinformation in detail  before. However, here I'll briefly discuss what it means  and why disinformation about vaccines is damaging. I`ll also give an example of the consequences it can cause. Then circling back to the title; I`ll talk about why this type of information circulating is damaging, particularly due to two features of the times we live in. These are unregulated information sharing online, the contagious nature of pathogens,  and also how interlinked we are at a global level allowing pathogens to spread more easily than ever.


  • What is disinformation?


So with that being said; what is disinformation exactly? Why is it so damaging? It is false information that is circulated with the intent to deceive. It's that word, intent, that is the defining feature of disinformation. It's not inaccurate information that was shared in error,  an honest mistake made by a fact-checking team, or even someone who was unsure about vaccines or a related topic asking questions. It is coordinated, planned, and  has malicious intent behind it. For example, a company sharing false information to increase profits, or a politician sharing false information to skew the results of an election in their favour; there are many such examples. 


Just two of these are described in an article published on on August 12th, 2022. It states that “Donald Trump derided any critical news coverage as “fake news” and his unwillingness to concede the 2020 presidential election eventually led to the January 6, 2021 riot at the US Capitol. For years, radio host Alex Jones denounced the parents of children slaughtered in the Sandy Hook school shooting in Newton, Connecticut as “crisis actors”. On August 5, 2022 he was ordered by a jury to pay more than US$49 million in damages to two families for defamation. Facebook estimates that during the 2016 US election, malicious content from the Russian Internet Research Agency aimed at creating division within the American voting public reached 126 million people in the US and worldwide.”

  • Why is it harmful?


With that understanding, it won't be surprising that this has the potential to cause significant harm. As I mentioned in the introduction, it can cause outbreaks of infectious diseases, influence the outcomes of political elections, and can drown out positive and accurate information in the saturated online environment. A 2022 paper by Daniel Jolley and Karen M. Douglas described two studies they conducted. The first involved parents completing a survey about beliefs in anti vaccine conspiracies and the likelihood that they would have a fictitious child vaccinated. Study 2 involved exposure of participants to either information supporting or refuting vaccination, as well as a control group. The results  “revealed a significant negative relationship between anti-vaccine conspiracy theories and vaccination intentions.” This illustrates the detrimental effects that anti vaccine conspiracies can have. 


In terms of these effects, I`ll discuss measles as an example. an article published in the Offaly Independent on 8th February 2024 reported 9 suspected measles cases in Ireland over the course of just 1 week,resulting in a risk of measles outbreaks. Further, the Health Service Executive/HSE, the Irish health authorities, said that one adult diagnosed with measles died in a hospital in the Leinster area (the east of Ireland). A similar pattern is occurring on the global level too. Further, the WHO European region also experienced a rise in measles cases in 2023 with over 30 000 cases reported by 40 of the 53 countries, including 21 000 hospitalisations. This is in comparison to 941 cases in 2022, which represents an over 30-fold increase in measles cases in the EU from 2022 to 2023. In the U.S, as of February 2024, a total of 35 measles cases were reported across 15 jurisdictions, including  Arizona, California, Florida, Georgia, Indiana, Louisiana, Maryland, Minnesota, Missouri, New Jersey, New York City, Ohio, Pennsylvania, Virginia, and Washington. Clearly, no region is immune to measles. This means that disinformation about the measles and other vaccines can have a detrimental impact when it can spread exponentially in very short periods of time over the internet. That's what I`ll discuss next.  


  • How  disinformation spreads so rapidly


Anyone has the capacity to mass-propagate information unregulated, even if they do not have authority to advise on vaccination. Some social media accounts opposing vaccines can garner millions of followers, views, likes, and so on. This can cause misinformation to be mass propagated and mistrust of vaccines to spread on a large scale. As with pathogens themselves, information online spreads exponentially not linearly. This means that the harm done by disinformation is very difficult, if not impossible, to reverse. To grasp the scale of the Internet, consider that in Australia, over 90% of people own a smartphone and a daytime usage increase of 70-80% was reported from April to February 2020.


Another contributing factor to disinformation spread is the sheer proportion of their time that people spend online. For instance, a 2011 study on problematic internet usage in US college students found that as much as 70% of participants reported remaining online longer than they had originally intended. Not only this; a 2015 study of 505 participants published in Public Library of Science estimated that on average, 5 to 6 hours per day or 39.57 hours per week, were spent online. Further, just under 20% of the participants reported spending over 61 hours per week online!  In the same sample, “30% displayed mild or worse levels of internet addiction.” Finally, a 2023 study of children's internet usage revealed an average daily duration of internet usage between 236 and 422 minutes. Such studies do not even include time spent online for education or work. With this said, it is crucial to note several points raised in a 2021 study by Michael Kaess and colleagues . Internet usage ranges on a spectrum from healthy to pathological. Further, in contemporary times, Internet usage is an integral aspect of life, and I would go so far as to say it is unavoidable to some extent. It depends on why individuals use the Internet, and their pattern of Internet usage. 

  • The infectious nature of measles 


However, some individuals consistently use the Internet with motives to spread disinformation about infectious diseases and vaccines. This can lead to disinformation and mistrust in vaccines spreading exponentially. In this way, online vaccine scepticism directly damages rates of vaccination coverage.  The danger from this arises when one considers how infectious specific bacterial and viral diseases are. I`ll once again take measles as an example; as it is an example of a disease making a recurrence due to disinformation.


 Measles is among the most infectious diseases known to man, and was described as early as the 9th century by Rhazes (Abū Bakr Muhammad Zakariyyā Rāzī), who was a Persian scholar and doctor. He described measles in the 10th century as “more to be dreaded than smallpox.” 


In 1757, a Scottish physician Francis Home demonstrated that measles is caused by a pathogen by transfusing blood of infected to healthy individuals; with the latter then developing symptoms of the disease. 3 to 4 million people became infected each year in the decade prior to 1963 when the first measles vaccine became available. Further, each year, among reported cases, 4-500 people died , 48,000 were hospitalised, and 1,000 suffered encephalitis from the measles infection. In this era, measles was endemic in Europe; with the majority of individuals becoming infected at least once before they were adults. By 6 years old, over 50% of people had become infected, and over 90% by age 15 years. The majority of people were immune by 20 years of age; however surges in cases would occur every 2-5 years.


It has always been clear that measles is highly contagious; however with contemporary models we can quantify exactly how infectious it is. Modern mathematical models estimating a reproductive number of 12-18. This means that, on average, for each individual that contracts measles, they will spread it to 12-18 other individuals. For comparison,depending on the strain and other variables, SARS-CoV2 can have an R0 ranging from 1 to 6 . Even the dreaded Ebola virus has a R0 ranging from 0.53 to 3.37, although there are differences within and between countries.  In those who are susceptible to measles, infectivity is close to 100%. This means that it will cause an infection in almost everyone who comes into contact with the virus that has not either had a previous infection or been vaccinated. It is maximally infectious during the prodromal phase. This is the time elapsed between the incubation period (the time from exposure to the infectious agent and the onset of symptoms)  and just prior to onset of the characteristic symptoms. This usually lasts 2 to 4 days; but at its extreme can range from 1 to 7 days. 


  • International travel


As well as this, there is a third key component that allows misinformation damage. This is the ease and cost effectiveness with which we can travel locally and internationally. By the end of July 2023, international travel reached 84% pre pandemic levels. In Europe, for instance in France, Denmark and Ireland, tourism surpassed pre pandemic levels. Further, in the U.S. alone, tourism is a US$2.6 trillion industry employing 15 million people. Not only this, people tend to travel distances for events such as Chicago's annual Lollapalooza music festival where there are densely packed crowds of up to hundreds of thousands of people. Also, reaching venues by any means is much more efficient. Every mode of transportation is more interconnected, quicker, and cheaper than ever. 


This is certainly economically beneficial; however it does exacerbate the issues I discussed prior to this. With the end of the public health emergency declared since May 11th 2023, travel restrictions have been lifted on a global scale.This has unsurprisingly led to a post-lockdown boom in tourism.  In particular, a 2022 study by Miguel Orden-Mejia and colleagues showed that post-lockdown,  tourists prefer urban tourism, followed by cultural tourism and travelling with relatives (although, this study did show that tourists are now adopting a more health-conscious approach while travelling). Outside of leisure travel; a national survey conducted in April 2022 revealed that roughly 90% of colleges and universities were planning to offer some form of study abroad by the summer of that year. 

All things considered, I'm not implying that people shouldn't use the Internet and/or travel. Both of these benefit us in many if not all aspects of our lives - when they`re used responsibly. Using the internet to spread disinformation can directly impact vaccination coverage, and therefore the spread of highly contagious diseases. 


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  • Conclusion;


When this capacity for information spread and the significant amount of time spent online by a majority of people worldwide are combined with how infectious measles and other diseases are, it's clear that disinformation can have a direct impact on lives all over the world. Added to that is how quick, cheap and efficient travel at both the national and international level is. In fact, one could argue that disinformation itself is a threat to global health as opposed to infectious diseases themselves or vaccine hesitancy itself. There won't be a single solution for this. There are many variables between people with respect to why and how they share disinformation. All disinformation is damaging, but all disinformation isn`t created equal. Although there have been predictions by authorities of the consequences this will result in (ie. Disease X),  there may be one or more  unexpected consequences; meaning that remaining cautious and adaptable is key - both online and offline. Thanks for reading!

  • References;


  1. Three reasons why disinformation is so pervasive and what we can do about it
  2. Measles Cases and Outbreaks | CDC
  3. Measles
  4. The Effects of Anti-Vaccine Conspiracy Theories on Vaccination Intentions - PMC
  5. Nine suspected cases of measles in Ireland recorded in one week | Offaly 
  6. Independent
  7. THREAT ASSESSMENT BRIEF - Measles on the rise in the EU/EEA: considerations for public health response
  8. A 30-fold rise of measles cases in 2023 in the WHO European Region warrants urgent action
  9. The coronavirus lockdown is forcing us to view ‘screen time’ differently. That’s a good thing
  10. Problematic internet usage in US college students: a pilot study - PMC
  11. Children’s Internet use and physical and psychosocial development - PMC
  12. Excessive and pathological Internet use – Risk-behaviour or psychopathology? - ScienceDirect
  13. Problematic Internet Usage and Immune Function - PMC
  14. History of measles vaccination
  15. Viral incubation: why do bugs hide before they strike?
  16. Chapter 13: Measles; Epidemiology and Prevention of Vaccine-Preventable Diseases 14TH Edition
  17. History of Measles | CDC
  18. Fact Sheet about measles
  19. The effect of travel restrictions on the spread of the 2019 novel coronavirus (COVID-19) outbreak - PMC
  20. New COVID variants may be more transmissible but that doesn’t mean the R0 – or basic reproduction number – has increased
  22. Heterogeneity in District-Level Transmission of Ebola Virus Disease during the 2013-2015 Epidemic in West Africa - PMC
  23. The basic reproduction number (R 0 ) of ebola virus disease: A systematic review and meta-analysis
  24. It’s time to limit how often we can travel abroad – ‘carbon passports’ may be the answer
  25. Revving up tourism: Formula One and other big events look set to drive growth in the hospitality industry
  26. Studying abroad is poised to make a post-pandemic comeback – here are 5 questions students who plan to study overseas should ask
  27. Post-COVID-19 Tourists’ Preferences, Attitudes and Travel Expectations: A Study in Guayaquil, Ecuador - PMC