MMR vaccine hesitancy – mindset and misinformation

Cover Image: Ella Yang, February 2026

By: Isla Stiff, Contributing Writer

Resurgence of Measles within Canada

Measles is a highly contagious viral infection caused by the measles virus (1). Transmission occurs through respiratory droplets, making it easily spread in unvaccinated populations (1). Thus, the Measles Mumps and Rubella (MMR) vaccine is essential. The vaccine works by exposing the immune system to a harmless form of Measles, Mumps and Rubella antigens, allowing the body to build antibodies (1). When antigens appear later, the premade immune defense can recognize and neutralize the virus before it can spread (1).  In Canada, the MMR vaccine has protected generations since its approval in 1963, with a second dose added in 1996 (2).  Due to the contagious nature of measles, achieving herd immunity is a critical public health priority. High vaccination coverage limits transmission and protects individuals who cannot be vaccinated- such as infants and pregnant women- by preventing community spread (3).

Given all we know about measles and the necessity of the MMR vaccine, why are we seeing a resurgence of the disease in 2025? What factors allow a preventable disease to re-emerge, even within healthcare systems that offer broad access to vaccination?

Background on vaccine hesitancy and its drivers

Vaccine hesitancy– is defined as the delaying acceptance or refusal of vaccination despite availability of vaccination services (4). It is shaped by numerous factors, such as personal beliefs, social influences and public discourse. It became especially prominent following Andrew Wakefield’s now-discredited 1998 paper in The Lancet, which falsely linked the MMR vaccine to autism (4). Today, the consequences of vaccine hesitancy are evident in Canada, reflected in a multijurisdictional measles outbreak has resulted in over 5000 confirmed cases of measles nationwide, with nearly 2000 occurring in Alberta alone (5). These recent outbreaks of a such a preventable disease reflect the consequences of eroding public trust in vaccines, due primarily to misinformation and the cognitive processes through which people form health related belief’s (3).

History of MMR vaccine misinformation

One of the most influential aspects of modern vaccine hesitancy traces back to Andrew Wakefield’s deeply flawed study, “Illeal-lymoid-nodular hyperplasia, non-specific colitis and pervasive developmental disorder in children” which falsely identified a link between the MMR vaccine and autism, misinformation that significantly undermined confidence in the vaccine (6). The study was an uncontrolled case series, lacking both a control group and a control period (6). However, the 12 children participating in the study had not been randomly selected: parents of eight of the twelve children reported that their child developed autism after getting the MMR vaccine (6). To make matters worse, Wakefield was paid to conduct his research by lawyers representing families whose children had allegedly been harmed by the MMR vaccine (6), further proving the bias and unfounded nature of his research.

The false claims from Wakefield’s study had a significant effect on the public’s perception of the MMR vaccine. Because it appeared in The Lancet –a popular and well trusted British medical journal– many people assumed the article had scientific significance. Wakefield’s article remained formally published in The Lancet until 2010 (7), giving individuals 12 years to receive misleading information about the MMR vaccine. Media outlets at the time presented claims both supporting and questioning the MMR vaccine, creating the impression that scientists held conflicting views about its safety (8). In reality, scientific evidence overwhelmingly supports the MMR vaccine’s safety and effectiveness (8). However, this information isn’t as widespread as the scientific community hoped it would be. Even in 2000, 67% of British people were unaware of claims about MMR’s safety, yet many recalled its alleged link to autism that provided the focus of Wakefield’s research (8), depicting how fast misinformation can spread, and the subconscious magnitude it has on the public.

Impacts of misinformation today

Although The Lancet formally retracted Wakefield’s paper in 2010 and numerous studies have since discredited his claims, the damage to public trust persists (9). Many parents have concerns about a false connection between the MMR vaccine and their children developing autism (9). The misinformation from Wakefield’s study eroded individuals’ trust in vaccines, healthcare and policy, making people shift to trust on non-experts (9). Some even believe that catching measles is worth the risk of potential vaccination side effects, even though such effects are far rarer than the disease and its complications (9).

To rebuild trust, healthcare professionals must engage with communities openly and transparently. Studies show that when doctors discuss side effects honestly, they strengthen rather than weaken vaccine confidence (9). Clear, science-based communication from trusted professionals plays a crucial role in reinforcing the safety and benefits of the MMR vaccine (9).

Individual and Social drivers of MMR vaccine hesitancy

MMR vaccine hesitancy has social influences: the people we talk to, the media we consume and the shared beliefs within our communities all shape how we perceive vaccines. In the 2022 study “Searching for the cognitive basis of anti-vaccination attitudes”, Lindeman examined whether holding epistemically suspect beliefs, ideas that lacking scientific evidence-makes individuals more likely to be vaccine hesitant. Researchers found communities who share these beliefs tend to have a general susceptibility towards anti-scientific thinking and are therefore more likely to reject vaccines (11). Lindeman also reported that faith in intuition, low science literacy and ontological confusion were stronger predictors of vaccine hesitancy than other factors (11). Ontological confusions occur when an individual mistakes the type of category a concept falls under- such as treating an abstract idea as a concrete entity, leading to faulty reasoning. These confusions often underlie supernatural beliefs and can contribute to vaccine hesitancy by causing people to misinterpret vaccines as unnatural, identity altering, or inherently harmful (11). These are just some examples of how social and cognitive factors at both individual and community levels can influence vaccine decisions and can discourage adherence to recommended immunization schedules (11). Vaccine hesitancy is therefore shaped more than science information alone: it is intertwined with identity, belief systems and one’s social environment.

Lessons from the 2025 measles resurgence in Canada 

Vaccine hesitancy surrounding the MMR vaccine is multifactorial, shaped by the lingering effects of past misinformation as well as modern social influences and cognitive factors tied to identity and belief systems. Across these factors, a consistent theme emerges. The level of trust an individual places in the healthcare system is central to their ability to make informed decisions (10). This trust is easily undermined, as demonstrated by the persistence of false claims linking the MMR vaccine causes autism more than 15 years after they were disproven (10).

Measles is a fully preventable virus and the tools to prevent it already exist– vaccines are safe, ensuring 99% protection after two doses (12). As science alone cannot solve vaccine hesitancy, it is essential for healthcare professionals to openly engage with concerns and make reliable information easily accessible. The 2025 outbreak reminds us that trust in science can’t be taken for granted. By rebuilding trust, this setback can become a opportunity to strengthen our response and bring us closer to fully eradicating measles.

References

1. Bailey A, Sapra A. MMR Vaccine. PubMed. Published 2022. https://www.ncbi.nlm.nih.gov/books/NBK554450/ 
2. Osman S, Crowcroft N, McLachlan E, et al. Population immunity to measles in Canada using Canadian Health Measures survey data – A Canadian Immunization Research Network (CIRN) study. Vaccine. 2022;40(23):3228-3235. doi:https://doi.org/10.1016/j.vaccine.2022.04.011 
3. Reiter L, Voracek M, Betsch C, Böhm R. Emphasising herd immunity in vaccine advocacy: a systematic review and meta-analysis. Health Psychology Review. Published online September 24, 2025:1-32. doi:https://doi.org/10.1080/17437199.2025.256284 
4. Labbé S, Bacon SL, Wu N, et al. Addressing vaccine hesitancy: A systematic review comparing the efficacy of motivational versus educational interventions on vaccination uptake. Translational Behavioral Medicine. 2025;15(1). doi:https://doi.org/10.1093/tbm/ibae069 
5. Government Of Canada. Measles and Rubella Weekly Monitoring Report — Canada.ca. Canada.ca. Published 2025. https://health-infobase.canada.ca/measles-rubella/ 
6. The Evidence on Vaccines and Autism | Johns Hopkins Bloomberg School of Public Health. Johns Hopkins Bloomberg School of Public Health. Published March 19, 2025. https://publichealth.jhu.edu/2025/the-evidence-on-vaccines-and-autism 
7. Rao TSS, Andrade C. The MMR Vaccine and Autism: Sensation, refutation, retraction, and Fraud. Indian Journal of Psychiatry. 2011;53(2):95-96. doi:https://doi.org/10.4103/0019-5545.82529 
8. Lewis J, Speers T. Misleading media reporting? The MMR story. Nature Reviews Immunology. 2003;3(11):913-918. doi:https://doi.org/10.1038/nri1228 
9. Novilla MLB, Goates MC, Redelfs AH, et al. Why parents say no to having their children vaccinated against measles: A systematic review of the social determinants of parental perceptions on MMR vaccine hesitancy. Vaccines. 2023;11(5):926. doi:https://doi.org/10.3390/vaccines11050926 
10. Adeoye AF, Umoru DO, Gomez OO, et al. The 2025 United States Measles Crisis: When Vaccine Hesitancy Meets Reality. Cureus. 2025;17(7). doi:https://doi.org/10.7759/cureus.88196 
11. Lindeman M, Svedholm-Häkkinen AM, Riekki TJJ. Searching for the cognitive basis of anti-vaccination attitudes. Thinking & Reasoning. 2022;29(1):1-26. doi:https://doi.org/10.1080/13546783.2022.2046158 
12. Government of Canada. Measles vaccine: Canadian immunization guide – Canada.ca. Canada.ca. Published 2018. https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-4-active-vaccines/page-12-measles-vaccine.html 

Image source: Cover Story | Overcoming Vaccine Hesitancy: Helping Patients Help Themselves. American College of Cardiology. https://www.acc.org/latest-in-cardiology/articles/2021/10/01/01/42/cover-story-overcoming-vaccine-hesitancy-helping-patients-help-themselves