The Vaccine Blog

Is the future under threat? Protecting against vaccine hesitancy in future pandemics

Is the future under threat? Protecting against vaccine hesitancy in future pandemics

  1. Introduction

There are many questions circulating around the internet about this one. If you look at the most commonly searched questions related to this, you`ll find “what are experts saying about the next pandemic? Are we genuinely prepared for it?” and most importantly “when will the next pandemic happen?” We don't have answers to all these questions. However  we don't need them to mitigate risks for the next pandemic to the greatest extent we can. The best way to mitigate risk is prevention; namely vaccination and other health promoting behaviours like masking, distancing and so on. Thus in this post I'll talk about strategies  to safeguard the future against vaccine hesitancy and anti vaccination movements. To put this into context, I`ll first outline pathogens that may cause future pandemics. 

  1. The next pandemic


Although we cannot definitively state what pathogen will cause the next pandemic exactly; major health authorities have several guesses. The majority of pathogens on the list won't be surprising to most people.  According to the website of the World Health Organization, pathogens of concern in this context include “COVID-19, Crimean-Congo haemorrhagic fever, Ebola virus disease and Marburg virus disease, Lassa fever, Middle East respiratory syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS), Nipah and henipaviral diseases, Rift Valley fever, Zika and Disease X.” Not mentioned on this list is the pandemic potential of emerging avian influenza viruses. Given that the 1918 influenza pandemic was the worst pandemic in modern history and was derived from an avian flu virus, it is worth acknowledging the very real threat influenza viruses pose. A 2021 study by Walter N. Harrington describes how “Both the United States Centers for Disease Control and Prevention and the WHO have also developed pandemic risk assessment tools that evaluate specific aspects of emerging influenza strains to develop a systematic process of determining research and funding priorities according to the risk of emergence and potential impact.“ The paper also notes that it is crucial to routinely monitor influenza in known animal reservoirs of the disease. They also note that understanding how influenza viruses evolve may reveal important patterns in mutations to consider. With that said, the authors caution that there is always the possibility of an entirely novel (new) strain emerging. This has been highlighted by the ongoing SARS-CoV2 pandemic. 


Many people are familiar with the concept of Disease X; however I'll briefly summarise. Disease X is a yet unknown disease that has the potential to cause severe outbreaks, epidemics, or a global pandemic. According to a paper published in the journal The Archives of Public Health in 2019, COVID-19 was itself a Disease X, and the list of diseases that may pose threats in the future is consistently being updated. 


 Antimicrobial and antiviral resistance are also major threats in terms of pandemic potential. Excessive and irresponsible use of antibiotics in agriculture, medicine, and other industries has led to the spread of resistance globally. According to a paper published by Ashima Gautam in 2022, antimicrobial resistance “ is expected to kill millions of people in less than a century, and is already brewing. In the distant future, the global, mostly silent pandemic of antimicrobial resistance is increasingly claiming the lives of patients on hospital floors.”  Antimicrobial resistance is such a significant threat that in 2019 the World Health Organisation listed it among the top 10 threats to global health among Ebola virus, climate change, and vaccine hesitancy. More shockingly, another report from the WHO in the same year confirmed that the world will eventually run out of antibiotics. This is because existing antibiotics were created by simply modifying existing drugs, thus current antibiotics have a short impact cycle. 


This explains why effective strategies  to mitigate the risks of future pandemics are urgently needed. However, how do we not only make sure health-promoting behaviours are encouraged, but maintained? If you follow my writing, you`ll have come across where I discussed misinformation and disinformation and their possible impacts here. Now, I mainly discussed this in the context of COVID-19 misinformation and vaccine disinformation. Generally, the majority of individuals recover from COVID 19 . In fact, a study found that “the global cumulative reported case fatality rate (rCFR) of COVID-19 increased up until the 17th epidemiological week (April 22–28, 2020) and then started to decline steadily.” However, we may not be this lucky next time around (and I use the word “lucky” extremely cautiously here, as over 7 million have died of the disease with 6.9% of U.S adults reporting having ever lived with Long COVID). What if there is a pandemic of rabies, infection with which results in death virtually 100% of the time after the appearance of clinical symptoms? Or if there is a pandemic of measles, in which for every individual infected, 12 to 18 other individuals on average will become infected?


It`s therefore very clear that addressing vaccine hesitancy and other behaviours detrimental to public health is crucial, regardless of what disease causes the next pandemic. I`ll mainly discuss vaccination here as it`is the main theme of the blog. However it's important to note that the principles can be applied to most health-promoting behaviours like masking, distancing, handwashing, and so on. Further, it's important to note that no one strategy  is 100% effective 100% of the time.  Due to that, we need to use multiple protective measures to reduce infection spread to the highest extent possible. This is known as the “Swiss Cheese” model of public health, though it is also applied to safety incidents and other areas.


  1. Use informed strategies


With vaccination as well as anything else one pursues throughout their life, certain motivations drive decision-making processes. They may be personal, professional,practical  or financial motives. Maybe they're nervous around health professionals, anxious about needles , or both.  Is taking time off work feasible? Can they afford to both travel to vaccination clinics and receive the vaccinations themselves? For those with children too young to vaccinate, can they afford childcare or is it possible to take the child with them? 


One, more, or even all of these may be contributing factors. Clarifying what these motives are is best done by asking clear questions that stimulate self reflection. The anonymous element of research questionnaires also means that participants are more likely to answer truthfully. This will lead to a clearer understanding of the key drivers of vaccination decisions. Understanding such patterns in decision making can then be used to guide public health strategies and health communication in future pandemics. Of course, there are caveats to this. These drivers of decision making will not be uniform across all populations. Factors vary with age, ethnicity, sex, and  health status, among many others. This is well described across the literature on vaccine hesitancy, so we do have a knowledge base with which to start.  


For example, according to a 2022 paper published by Doug Storey investigated COVID 19 vaccine hesitancy, “Formative research to inform COVID-19 vaccination communication efforts should be asking people who have been vaccinated questions such as:


  • What made you decide to get the vaccine?
  • What do you consider to be the benefits of getting vaccinated?
  • Was there anything that made it hard for you to get vaccinated?
  • How did you overcome that challenge?
  • Where did you get the information that helped you make the decision and get vaccinated?


People who have not yet been vaccinated should be asked the following questions:


  • What are some of the reasons you have not been vaccinated yet?
  • How likely do you think it is that you might become infected with COVID-19?
  • How serious do you think it would be if you did become infected with COVID-19?
  • What proportion of your friends and family has been vaccinated?
  • Where do you get information that helps you decide whether to get vaccinated or not?”


Although this paper focused on COVID 19 vaccination hesitancy, these questions can be adapted to the majority of infectious diseases and vaccinations. 

  1. Regular recommendations from physicians by addressing physician    hesitancy


Another effective but underused method is simply consistently recommending vaccinations. It's well-known from psychological research that repetition increases credibility of the communicator and also the apparent truthfulness of the message itself. This is known as the “illusory truth effect”. For example, a 2021 study by Aumyo Hassan and Sarah J Barner involved two experiments. Participants were shown trivia statements 9 times in experiment 1, but 27 times in experiment 2. Following this, participants were asked to rate the perceived truthfulness of the statements. Perceived truthfulness increased with repetition. However, they note that “truth rating increases were logarithmic in shape. The largest increase in perceived truth came from encountering a statement for the second time, and beyond this were incrementally smaller increases in perceived truth for each additional repetition.”


This has important implications for vaccine messaging , as it demonstrates the importance of consistent messaging. It is well known from research that physicians are the primary and most trusted source of medical guidance across different populations Therefore, it follows that they would be the optimal individuals to deliver strong vaccine messaging and recommendations. Indeed, many physicians make these recommendations. However, some do experience reluctance to make strong recommendations. Although the reasoning for this varies among physicians, some key trends have been identified in research. These include wishing to preserve the relationship with their patient, a focus on “individual medicine”, and alternative vaccination schedules. 


Interestingly, some physicians are themselves hesitant. For instance, a 2020 study investigated hesitancy among primary care physicians in the South of France, and their reluctance to trust in health authorities. The study found that ,” facilitated by health scandals and vaccine controversies—that according to participants were not effectively handled by health authorities—the implicit contract existing between health authorities and GPs has been ruptured. This contract implies that health authorities support GPs in making vaccine recommendations by addressing GPs’ own concerns, providing them with adequate and up-to-date information and advice, and involving them in vaccine decision-making.” That is, it is not always about the vaccines themselves - in this instance it is about trust. If physicians do not trust health authorities (and by extension, vaccinations), how can they expect patients to?   


Therefore, trust needs to be addressed not just at the patient-physician level but at the physician-health authority level. There is much research available on the former but not the latter.  Hopefully, researching into the various factors causing physician hesitancy will restore confidence in physicians globally, resulting in them  making strong, regular vaccine recommendations.


  1. Motivational Interviewing - a self directed approach to addressing patient hesitancy


These approaches are all found to be extremely effective. However,  to really cement the ideas in and have people commit to long term behavioural changes another key element is needed. That is they are self-directed changes, rather than being authoritatively steered through them by health professionals. In other words,  the patient is positioned as the key stakeholder in medical decision making with their physician as the primary source of medical guidance. Few strategies demonstrate this better than motivational interviewing, so I'll close  with a discussion of this and evidence for its effectiveness. 


Motivational interviewing (MI) involves the patient being prompted to consider their current health-related behaviours and the positive or negative consequences of them. They then reflect on what changes they would like to make and how they will reach specific goals.  Nobody is telling them what to do, to state it simply. They are not passively accepting recommendations from the physician or from faceless health authorities. MI allows patients to justify health-promoting changes to their behaviour and/ or lifestyle in a way that aligns with their own personal values. This is important because it preserves patient autonomy. Autonomy is important in decision making in  all aspects of life, but even more so in healthcare decisions as the stakes can be significantly higher. I`ll add here that the results may occur during the interview, immediately after, or after the patient has had more time to reflect 


It will be unsurprising then, that MI has been found to be highly effective across the literature. For example, a 2023 study published by Pierre Verger and colleagues investigated the effectiveness of motivational interviewing carried out by midwives on 733 mothers in maternity wards postpartum (ie. after giving birth).  The study found that mothers vaccination hesitancy reduced by 33% , and their intention to vaccinate increased by 8%.  The authors concluded that “the impact of MI on mothers’ VH and intentions to vaccinate, the apparent reduction of social disparities in vaccine acceptance and parental satisfaction with several aspects of the programme all argue for investigating conditions for larger-scale implementation of MI intervention in France possibly through an implementation study, including an assessment of its impact on vaccination delays between the recommended and actual age at vaccination and a cost-effectiveness analysis. “


The key is that via this  framework of interlinked strategies, positive relationships will be established between the public, health professionals and health authorities. This means that a strong base of trust will be established when future pandemics occur, making it more likely that the public will accept guidance and take health precautions.


  1. Conclusion


Although we cannot predict what pathogen will cause the next pandemic or when it will come, we can define groups of pathogens that have serious pandemic potential. This explains the motivation behind public health efforts to mitigate the risk of future pandemics happening. With this serious threat looming, any strategies must be well-informed, and also address physician concerns. Strategies addressing patient hesitancy are found to be most effective when they are guidance-based rather than authoritarian. Motivational Interviewing is a prime example of such an approach that could be implemented on a larger scale.  This is of course not a comprehensive list of strategies for addressing hesitancy. These should form part of a framework of many interlinked approaches to address vaccine hesitancy and other risk factors for pandemics in both the near and distant future. Thanks for reading! 

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  1. References;


1, WHO to identify pathogens that could cause future outbreaks and pandemics

  1. Preparing for Disease X: Ensuring Vaccine Equity for Pregnant Women in Future Pandemics - PMC
  1. Online learning for WHO priority diseases with pandemic potential: evidence from existing courses and preparing for Disease X - PMC
  2. Antimicrobial Resistance: The Next Probable Pandemic - PMC
  3. Ten threats to global health in 2019
  4. The world is running out of antibiotics, WHO report confirms
  5. The Pandemic Threat of Emerging H5 and H7 Avian Influenza Viruses - PMC
  6. The evolution and future of influenza pandemic preparedness - PMC
  7. Infection fatality rate of COVID-19 inferred from seroprevalence data - PMC
  8. The Global Case-Fatality Rate of COVID-19 Has Been Declining Since May 2020 - PMC
  9. Notes from the Field: Long COVID Prevalence Among Adults — United States, 2022 | MMWR
  10. Rabies.
  11. Updates on Measles Incidence and Eradication: Emphasis on the Immunological Aspects of Measles Infection - PMC
  12. The Swiss cheese model of safety incidents: are there holes in the metaphor? - PMC
  13. COVID-19 Vaccine Hesitancy - PMC
  14. Original research: Determinants of COVID-19 vaccine hesitancy and uptake in sub-Saharan Africa: a scoping review - PMC
  15. The effects of repetition frequency on the illusory truth effect - PMC

CC BY 4.0 Deed | Attribution 4.0 International | Creative Commons

  1. Understanding Vaccine Hesitancy in Canada: Results of a Consultation Study by the Canadian Immunization Research Network - PMC
  2. ‘I’m not an anti-vaxxer!’—vaccine hesitancy among physicians: a qualitative study - PMC
  3. Vaccine hesitancy among general practitioners in Southern France and their reluctant trust in the health authorities
  4. A postpartum intervention for vaccination promotion by midwives using motivational interviews reduces mothers’ vaccine hesitancy, south-eastern France, 2021 to 2022: a randomised controlled trial