Misinformation and misunderstandings: Five of the most common vaccine myths

Many people have questions and concerns about vaccines, especially with the overwhelming amount of information on the news and social media about COVID-19. However, not everything we read or hear is true. There is also a significant amount of misinformation online, which makes it very hard for people to make an informed choice about vaccination.

Here are some of the most common vaccine myths and the facts that debunk them:

#1 Vaccines cause autism

Now widely discredited, this is one of the longest-running and widespread myths about vaccination. The original research paper on which the rumour was founded has been retracted,1 and the author banned from practicing medicine in Britain for serious professional misconduct, including a ‘callous disregard for the distress and pain’ of the children he studied, and falsifying data.2-4

It started in 1998, when Andrew Wakefield published a case series of 12 children in the Lancet claiming that there were intestinal abnormalities of children who had exhibited autism symptoms after receiving the measles, mumps and rubella (MMR) vaccination.5 He also released a video claiming a causal relationship between the vaccine and autism.6

In the years since Andrew Wakefield published the case series, many studies, including an analysis that assessed the relationship between vaccination and development of autism in over 1 million children, have found there is no link between the MMR vaccine and autism.7,8

#2 Vaccines contain toxic ingredients

Many people are cautious of vaccines as they have heard that they contain ingredients that are toxic. However, all ingredients in a vaccine have been well studied, and vaccines undergo rigorous testing in clinical trials to demonstrate their efficacy and safety.9

The main ingredient in vaccines are antigens, which train your immune system against the virus or bacteria to fight against future infections.10 While there are very small amounts of ingredients, such as preservatives, formaldehyde, mercury and aluminium, in some vaccines, they have not been found to be harmful to humans or animals in experimental studies.10,11 Indeed, formaldehyde is already present in the human body as a by-product of metabolism at a level higher than that found in vaccines.11

#3 I don’t need to get vaccinated as I have already had the disease – natural immunity is better than vaccine-acquired immunity

While it is true that natural infection can result in better immunity than vaccines, this is not always the case.12 One study discovered that a third of all participants that had been infected with SARS-CoV-2 had no apparent natural immunity against the virus,13 and tetanus and human papillomavirus vaccines actually provide more immunity than natural infection.12 But either way, natural immunity means that an individual first has to become infected with the disease, which can pose a great risk for serious complications.14

Take the example of measles. Before 1963, when the vaccine was not available, approximately 500,000 cases and 500 measles deaths were reported annually.15 COVID-19 in unvaccinated people can result in long-term disease, lasting organ damage, hospitalization, or even death.14 Having COVID-19 also means that you can transmit it to others who may develop severe disease.14

Vaccination is the best protection from some infectious diseases, whether or not you have already caught it14,16:

  • A study found that natural immunity from a SARS-CoV-2 infection can reduce the risks for reinfection and hospitalization, but risks can be reduced even further by vaccination.17
  • Another study found that if you have had COVID-19 and are not vaccinated, you are twice as likely to get reinfected than those who were fully vaccinated after having COVID-19.18

#4 Unvaccinated people in the past have led long and healthy lives, so there is no real need for vaccines

We are now living longer than any other period in history. In 1900, life expectancy in the US was 47 years,19 and today it is 76 years.20 Vaccines have played an important part in this.19

Smallpox is an excellent example of the success that can be achieved through vaccination. Before vaccination, 3 out of every 10 people who caught it died.21 Smallpox vaccination has saved the lives of around 150 to 200 million people,22 and the disease was declared to have been eradicated worldwide in 1980.21

#5 I don’t need to be vaccinated if everyone around me is vaccinated or already had COVID-19

Some people think that they do not have to get vaccinated as people around them are immune to an infection through natural infection or vaccination, which is termed ‘herd immunity’. For some viruses, herd immunity can prevent its onward spread,23 and help to protect clinically vulnerable people, such as those with cancer, who may have a compromised response to a vaccine.24

Unfortunately, herd immunity for COVID-19 may not be possible.25 There are various reasons that are being discussed for this, including whether vaccination or infection elicits a long-term protective immune response against SARS-CoV-2, and the emergence of variants.25

According to the Oxford Vaccine Group, herd immunity also does not give a high level of individual protection, so it is not a good alternative to getting vaccinated.23 Vaccination is one of the most important measures to successfully control the spread of the virus within communities.26

  1. The Editors of the Lancet. Retraction─Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet. 2010;375(9713):445.
  2. Kmietowicz Z. Wakefield is struck off for the “serious and wide-ranging findings against him”. BMJ. 2010;340:c2803.
  3. Nowottny S. Dr Andrew Wakefield struck off register. Pulse 24 May 2010. Available at: https://www.pulsetoday.co.uk/news/uncategorised/dr-andrew-wakefield-struck-off-register/ [Accessed: October 2022].
  4. Deer B. How the case against the MMR vaccine was fixed. BMJ. 2011;342:c5347
  5. Wakefield A, et al. Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet. 1998;351:637-641.
  6. Royal Free MMR video news release, 1998; transcript. Available at: https://briandeer.com/wakefield/royal-video.htm [Accessed: October 2022].
  7. Institute of Medicine (US) Immunization Safety Review Committee. Immunization safety review: vaccines and autism. National Academies Press, 2004. Available at: Immunization Safety Review: Vaccines and Autism – NCBI Bookshelf (nih.gov) [Accessed: October 2022].
  8. Taylor LE, et al. Vaccines are not associated with autism: an evidence-based meta-analysis of case-control and cohort studies. Vaccine. 2014;32(29):3623-3629.
  9. FDA. Common ingredients in US licensed vaccines. Available at: https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/common-ingredients-us-licensed-vaccines [Accessed: October 2022].
  10. Vaccine Knowledge Project. Vaccine ingredients. Available at: https://vk.ovg.ox.ac.uk/vk/vaccine-ingredients [Accessed: October 2022].
  11. Offit PA, Jew RK. Addressing parents’ concerns: do vaccines contain harmful preservatives, adjuvants, additives, or residuals? Pediatrics. 2003;112(6 Pt 1):1394-1397.
  12. Children’s Hospital of Philadelphia. Vaccine safety: immune system and health. Available at: https://www.chop.edu/centers-programs/vaccine-education-center/vaccine-safety/immune-system-and-health [Accessed: October 2022].
  13. Liu W, et al. Predictors of nonseroconversion after SARS-CoV-2 infection. Emerg Infect Dis. 2021;27(9):2454–2458.
  14. Johns Hopkins Medicine. COVID natural immunity: What you need to know. Available at: https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/covid-19-vaccine-what-you-need-to-know [Accessed: October 2022].
  15. CDC. Epidemiology and prevention of vaccine-preventable diseases. Measles. Available at: https://www.cdc.gov/vaccines/pubs/pinkbook/meas.html#complications. [Accessed: October 2022].
  16. GOV.UK. The flu vaccination: who should have it and why. Available at: https://www.gov.uk/government/publications/flu-vaccination-who-should-have-it-this-winter-and-why/the-flu-vaccination-who-should-have-it-and-why [Accessed: October 2022].
  17. Nordström P, et al. Risk of SARS-CoV-2 reinfection and COVID-19 hospitalisation in individuals with natural and hybrid immunity: a retrospective, total population cohort study in Sweden. Lancet Infect Dis. 2022;22(6):781-790.
  18. Cavanaugh AM, et al. Reduced risk of reinfection with SARS-CoV-2 after COVID-19 vaccination – Kentucky, May–June 2021. MMWR Morb Mortal Wkly Rep. 2021;70(32):1081-1083.
  19. Rappuoli R, et al. Vaccines, new opportunities for a new society. Proc Natl Acad Sci USA. 2014;111(34):12288–12293.
  20. CDC. Life expectancy in the US dropped for the second year in a row in 2021. Available at: https://www.cdc.gov/nchs/pressroom/nchs_press_releases/2022/20220831.htm [Accessed: October 2022].
  21. CDC. History of smallpox. Available at: https://www.cdc.gov/smallpox/history/history.html [Accessed: October 2022].
  22. Our World in Data. Smallpox. Available at: https://ourworldindata.org/smallpox#smallpox-eradication-program [Accessed: October 2022].
  23. Vaccine Knowledge Project. Herd immunity (Herd protection). Available at: https://vk.ovg.ox.ac.uk/vk/herd-immunity [Accessed: October 2022].
  24. Vaccine Knowledge Project. Disease in vaccinated populations. Available at: https://vk.ovg.ox.ac.uk/vk/disease-vaccinated-populations [Accessed: October 2022].
  25. Morens DM, et al. The concept of classical herd immunity may not apply to COVID-19. J Infect Dis. 2022;226(2):195–198.
  26. WHO. Vaccines and immunization. Available at: https://www.who.int/health-topics/vaccines-and-immunization#tab=tab_1 [Accessed: October 2022].
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