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Vaccine Opposition and Hesitancy

Chapter 3 | Part_1: The Profession of Medicine · Part 1 – The Profession of Medicine · Chapter 3

Key Clinical Points

  1. Herd immunity for measles requires 93–95% coverage; current US/Canada 1-dose coverage is 92%.
  2. WHO SAGE defines vaccine hesitancy as a 'delay in acceptance or refusal of vaccines despite availability of vaccination services.'
  3. Vaccine acceptance exists on a continuum from 'Active Demand' to 'Refusal'.
  4. Three primary determinants of hesitancy: Complacency (low perceived risk), Convenience (access barriers), and Confidence (trust in systems).
  5. Social media creates 'echo chambers' where personal anecdotes often outweigh authoritative data.
  6. Effective recommendations must be Strong, Tailored, Transparent, Supported, and Revisited.
  7. Presumptive/directive communication is used for the bottom half of the acceptance continuum (Hesitant - minor doubts; Active demand), while participatory/guiding communication is used for the top half (Late and selective; Refuses).
  8. A 'missed opportunity' for vaccination is defined by WHO as any eligible contact with health services.
  9. Aluminum in vaccines is similar to or less than amounts found in breast milk or infant formulas.
  10. Outbreaks often originate from unvaccinated travelers or non-vaccinating religious communities.

1. DEFINITION & OVERVIEW

• Definition: Vaccine hesitancy and opposition are defined by the WHO’s SAGE Working Group on Vaccine Hesitancy as a 'delay in acceptance or refusal of vaccines despite availability of vaccination services.' • Context: A complex, context-specific phenomenon varying by time, place, and vaccine type. • Consequences of Hesitancy: ◦ Decreased vaccine demand and uptake ◦ Lower childhood and adult vaccine coverage ◦ Increased incidence of vaccine-preventable diseases, outbreaks, and epidemics

2. EPIDEMIOLOGY

• Herd Immunity: Required 93–95% coverage for measles. • Current Status: ◦ US/Canada 1-dose coverage: 92% ◦ Note: Coverage rates do not distinguish between hesitant individuals and those with access barriers. • Outbreak Trends: ◦ 2010–2019 outbreaks primarily occurred in unvaccinated individuals. ◦ 80–95% of cases linked to religious communities or unvaccinated travelers. ◦ 2019 US outbreak: 73% of cases in New York nonvaccinating communities. • Global Context: ◦ 2022: Only 34% of countries met WHO measles vaccine coverage targets (a 10% decrease from pre-pandemic levels). ◦ Shift: 20 years ago, herd immunity protected unvaccinated travelers; this is no longer the case.

Table 1 — Measles Outbreaks in North America (2010–2019)

YEAR/PLACE NO. OF CASES REASON
2010/Canada 70 Infected traveler at Winter Olympics; spread to under- and unvaccinated local population.
2011/Canada 776 Imported from France; spread in religious community.
2011/United States 118 46 were returned travelers; 105 (89%) occurred in unvaccinated persons.
2014/Canada 433 Imported from Netherlands; spread in nonvaccinating religious community.
2015/United States 147 Linked to Disneyland; >80% of cases were in unvaccinated persons.
2017/United States 75 Undervaccinated community in Minnesota; 95% were unvaccinated.
2019/Canada 31 & 1282 31 imported from Vietnam; 1282 spread through local schools of under- and unvaccinated persons.

3. ETIOLOGY & PATHOPHYSIOLOGY

• Drivers of Hesitancy: Pseudoscience, real safety events, failed health systems, and cultural/religious beliefs. • Determinants of Hesitancy: ◦ Complacency: Low perceived risk of disease (influenced by lack of recent outbreaks or misinformation). ◦ Convenience: Access barriers including cost, geography, and language. ◦ Confidence: Trust in vaccines, healthcare systems, and pharmaceutical companies. • Information Environment: Social media creates 'echo chambers' where personal anecdotes outweigh authoritative data.

4. CLINICAL FEATURES

• Vaccine Acceptance Continuum (Figure 1): ◦ Refuses: Distrust of systems, poor information, lack of confidence. ◦ Late and selective: Concerns about safety/necessity; lack of strong relationship with provider. ◦ Hesitant - minor doubts and concerns: Requires conversation with trusted providers to clarify conflicting info. ◦ Active demand - no doubts or concerns: High confidence, belief in safety, 'no' questions for the provider.

Vaccine Acceptance Categories

• Active Demand: Full acceptance of all vaccines. • Hesitant (Minor Doubts): Accepts most vaccines. • Hesitant (Many Doubts): Selective acceptance. • Late and Selective: Delayed or partial acceptance. • Refuses: Rejects all vaccines.

5. DIFFERENTIAL DIAGNOSIS

• Distinguishing Hesitancy from Access Barriers: ◦ Hesitant: Patient refuses vaccine despite availability. ◦ Access Barrier: Patient is unvaccinated due to logistical or financial obstacles (e.g., cost, geography, language).

6. DIAGNOSTIC APPROACH

  1. Initial Assessment: Identify patient's position on the vaccine acceptance continuum.
  2. Barrier Identification: Use patient interviews to distinguish between refusal (hesitancy) and logistical/financial obstacles (access).
  3. Trust Evaluation: Assess level of trust in healthcare systems and perceived risks of vaccines.

7. MANAGEMENT & TREATMENT

• Core Strategy: Utilize a multi-pronged approach: Strong, Tailored, Transparent, Supported, and Revisited. • Communication Styles: ◦ Presumptive/Directive: Used for the bottom half of the continuum (Hesitant - minor doubts; Active demand). Example: 'Your child is due for MMR vaccination.' ◦ Participatory/Guiding: Used for the top half of the continuum (Late and selective; Refuses) to build trust. Example: 'What are your thoughts about the MMR vaccine?' • Implementation Steps: 1. Strong Recommendation: Explicitly state vaccination is the best option (absent contraindications). 2. Tailored Communication: Acknowledge patient attitudes and specific history (e.g., 'I see from your record that you’ve had your childhood vaccines, but you haven’t gotten any adult vaccines. I wanted to clarify whether this is because you decided not to get vaccines or something else prevented you...'). 3. Transparency and Accuracy: Highlight benefits outweigh risks. ◦ Example: MMR risk of encephalitis (1/1000) vs. febrile seizures (3/10,000). ◦ Example: Aluminum in vaccines is similar to or less than what is present in breast milk or infant formulas. 4. Support from Sources: Provide links to reliable resources (e.g., CDC, Immunization Action Coalition; specific mention of HPV and LGBTQ-friendly resources). 5. Revisiting and Reinforcement: Schedule follow-ups and reinforce recommendations during subsequent visits.

Table 2 — Sample Vaccine Conversations

• Strong Recommendation: 'We are headed into the respiratory virus season. Getting flu, RSV, and COVID vaccines not only protects you, but it helps protect other people around you who can get very sick from flu, RSV, or COVID. I strongly recommend you get shots. Do you know where to get them?' • Tailored Communication: 'I see from your record that you’ve had your childhood vaccines, but you haven’t gotten any adult vaccines. I wanted to clarify whether this is because you decided not to get vaccines or something else prevented you from getting vaccinated.' • Transparency and Accuracy: 'MMR vaccine has rare risks but prevents severe measles complications.' / 'You are correct, aluminum is used in some vaccines... the amount of aluminum present in vaccines is similar to or less than what is present in breast milk or infant formulas.' • Support from Sources: 'Here is a list of websites that have been reviewed by health care professionals and accurately describe benefits and risks of each vaccine...' • Revisiting and Reinforcement: 'Have you had a chance to look at the take-home information I gave you?'

8. PROGNOSIS & COMPLICATIONS

• Waning Immunity: Vaccine effectiveness diminishes over time for some diseases (e.g., pertussis) → Booster doses required. • Outbreak Risks: ◦ Driven by unvaccinated travelers and communities. ◦ Risk increases in areas with high misinformation or low coverage.

9. SPECIAL CONSIDERATIONS

• Individualized Care: Tailor communication to unique patient values/beliefs; use shared decision-making for hesitant individuals. • Parenting Trends: Anti-vaccine movements linked to alternative parenting philosophies and social media influencers. • Media Impact: Traditional news plays a role in education; social media algorithms prioritize emotional content over facts. • WHO EARS Platform: Used to track vaccine hesitancy trends globally for targeted interventions.

10. KEY PEARLS & CLINICAL TRAPS

• Communication Strategy: Avoid confrontational language; use empathetic listening techniques. • Key Consultation Questions: ◦ 'What concerns do you have about vaccines?' ◦ 'How do you decide which vaccines to accept?' ◦ 'Have you heard about recent vaccine safety updates?'

Reference Tables

TABLE 3-1 Measles Outbreaks in North America YEAR/PLACE 2010/Canada 2011/Canada

Harrison's 22e, p.15

YEAR/PLACE NO. OF CASES REASON
2010/Canada 70 An infected traveler to the 2010 Winter Olympics transmitted infection to an under- and unvaccinated local
population in British Columbia.
776
2011/United States 118 Of 118 cases, 46 were in returned travelers from Europe and Asia/Pacific regions; 105 cases (89%) occurred in
unvaccinated persons.
58
2014/Canada 433 Disease was imported from the Netherlands. The outbreak spread in a nonvaccinating religious community in
British Columbia.
383
2015/United States 147 A multistate/multicountry outbreak was linked to Disneyland amusement park. More than 80% of cases occurred in
unvaccinated persons.
159
2017/United States 75 The outbreak occurred in an undervaccinated community in Minnesota; 95% of patients were unvaccinated.
375
2019/Canada 31 Disease was imported from Vietnam by a returned traveler to British Columbia. The outbreak spread throughout
local area schools in under- and unvaccinated persons and resulted in a province-wide measles mass immunization
campaign for schoolchildren.
1282

TABLE 3-2 Sample Vaccine Conversations

Harrison's 22e, p.18

  • STRONG VACCINE RECOMMENDATION
  • “We are headed into the respiratory virus season. Getting flu, RSV, and COVID vaccines not only protects you, but it helps protect other people around you who can get
    very sick from flu, RSV, or COVID. I strongly recommend you get shots. Do you know where to get them?”
    “You will be turning 50 next year. This means you will be eligible for a vaccine that prevents shingles, and I strongly recommend you receive it. Have you heard about
    this vaccine before? Can I answer your questions about it?”
    “I know you are not comfortable getting vaccinated today. I do want to make it clear that I recommend vaccines because I am convinced they are the best way to
    protect you from some serious diseases. Is there something that would lead you to think about getting vaccinated in the future?”
  • TAILORED COMMUNICATION
  • “I recommend that children and adults stay up to date on recommended vaccines. I see from your vaccine record that you’ve had your childhood vaccines, but
    you haven’t gotten any adult vaccines. I wanted to clarify whether this is because you decided not to get vaccines or something else prevented you from getting
    vaccinated.”
    “I understand that you are here for your pneumococcal vaccine. This is the best way to protect yourself and those around you from pneumonia. Do you have any
    questions before I give you the vaccine?”
    “There is strong evidence that COVID-19 vaccines work well for all people, regardless of their ethnic or genetic background. What particular concerns did you have
    about the vaccine?”
    “Thank you for telling me about your fear of needles. This is quite common in children and in adults. Would you like to talk about some potential strategies to help you
    with getting vaccinated?”
  • TRANSPARENCY AND ACCURACY
  • “Serious side effects can develop after MMR vaccination but are very rare. On average, 3 out of 10,000 children who get MMR vaccine will have a febrile seizure/
    convulsion in the days after vaccination. Febrile seizures can be frightening, but nearly all children who have a febrile seizure recover very quickly and without any
    long-term consequences. On the other hand, 1 out of 1000 children who get measles will develop encephalitis (brain inflammation) that not only causes seizures but can
    also lead to permanent damage.”
    “About 10 out of every 10,000 Americans who do not get vaccinated against flu die because of influenza every year, and many more are hospitalized. While flu vaccine
    does not prevent all cases of influenza, it is the most effective vaccine we have. By getting the vaccine, you also help protect people around you from getting sick.”
    “You are correct, aluminum is used in some vaccines to help the body’s immune system respond. However, aluminum is also present in food and drinking water. In fact,
    the amount of aluminum present in vaccines is similar to or less than what is present in breast milk or infant formulas.”
  • SUPPORT FROM ACCESSIBLE INFORMATION SOURCES
  • “Your child and other boys and girls his age will be eligible for the human papillomavirus vaccine this coming school year. Have you heard about this vaccine before?
    What questions do you have about it? Here’s a list of websites for parents and teenagers that explain what it is about.”
    “There’s a lot of information about vaccines on the Internet, and a lot of that information is not based on facts. Here is a list of websites that have been reviewed by
    health care professionals and accurately describe benefits and risks of each vaccine, including information resources written by the LGBTQ community that many of my
    patients have found useful.”
  • REVISITING AND REINFORCEMENT OF THE RECOMMENDATION
  • “During our last visit, we talked about why COVID vaccine is recommended for your son and some of the concerns you had about potential side effects, especially
    myocarditis. It is important to weigh the risks of side effects against the risks of infection. Have you had a chance to look at the take-home information I gave you? Was
    there anything else you or your partner would like to ask about?”
    “When you were here last month, we talked about receiving a pertussis booster during pregnancy and where you can get vaccinated. Have you had a chance to get
    your pertussis vaccine?”
    “I see that you got your vaccines at the public health clinic last week. How did it go? Did you have any questions?”
    “It’s possible that the symptoms you experienced after receiving the vaccine were an adverse reaction to the vaccine. I will report this to the health authority. Let’s
    discuss what we can do next time to prevent symptoms from occurring again.”