Cherry-picking: The claim relies on a personal anecdote and an open letter from a former scientist, while ignoring the vast amount of scientific literature that contradicts it.
FULL CLAIM: "Unvaccinated children pose no threat to anyone"
This article by Collective Evolution, published on 6 March 2019 and shared more than 56,000 times online, reports the claim that “unvaccinated children pose no threat to anyone” made in a four-year-old open letter by former scientist Tetyana Obukhanych. In the letter, she outlines several ways in which she asserts that non-vaccination will not substantially endanger anyone and that vaccines themselves are dangerous to children.
The claim that “unvaccinated children pose no threat to anyone” is incorrect however, and the author of the article has ignored the vast amount of scientific literature that contradicts the claim. One only needs to look at the current outbreaks of measles in the United States to know what happens when herd immunity to a highly transmissible disease dips even slightly (effective herd immunity to measles occurs at 95% vaccination rate; the vaccination rate in the US for young children currently stands at 91.1%). The presence of unvaccinated individuals within a community lowers herd immunity, and makes it more likely for disease transmission to occur.
Unvaccinated people are also more likely to contract the disease themselves. A review of measles and pertussis cases in the US shows that the majority of those who caught measles and a large proportion of those who caught pertussis were intentionally unvaccinated.
This is not merely a personal concern, but also implicates the health of other people within the community who are unable to receive a vaccine for medical reasons, which can be due to age and pre-existing medical conditions. There are also people who have been vaccinated before but are now unable to mount adequate immune defense against infection, specifically those who are immunocompromised, a population comprising transplant patients on immunosuppressants and cancer patients on chemotherapy, among others. Vaccines also tend to be much less effective in immunocompromised people. These individuals have no choice but to rely on the immunised population to protect them. Cases like these show clearly what happens to these vulnerable people during times of diminished herd immunity.
It is true that vaccinated individuals can still be infected, as shown in an article cited in Obukhanych’s open letter. Vaccine failure has been reported in the scientific literature, and can arise depending on factors such as the number of vaccine doses a person has had, vaccine formulation, an individual’s genetics, age, and pre-existing medical conditions (like immunosuppression). These variables make it difficult to predict whether vaccine failure will occur in an individual. Nevertheless, measles vaccine effectiveness are high, as reported by the CDC and WHO, ranging between 80-90%, depending on the number of doses – in short, measles vaccination is successful in most cases.
The argument that we should stop using vaccines because vaccines do not always work is logically unsound; on the basis of this argument, one could assert that because seat belts don’t prevent all car crash fatalities, seat belts are useless and we should stop using them. The fact is that measles vaccination has prevented hundreds of thousands of deaths, not to mention disability from measles complications, and the results of a vaccination campaign from 2010 to 2013 in India, recently published, further support this fact.
Obukhanych claims that vaccination leads to many adverse events, citing just one study by Wilson et al. showing a statistically significant increase in the number of emergency room visits after live vaccine shots at 12 and 18 months. However, she appears to have missed that the article also reported that the increased ER visits did not culminate in increased hospital admissions – strongly suggesting that the majority of the adverse events were not serious or life-threatening (the authors also come to the same conclusion). That an increase in ER visits might be the result of parental anxiety and/or lack of information was not considered.
In fact, Wilson et al. write in their Discussion that “the increase in ER visits we observed could be a result of insufficient information being provided to parents who may not expect their child to develop a reaction a week after vaccination.” Furthermore, the authors conclude with their support for vaccination: “Given the effectiveness of the MMR vaccine in eliminating both measles and rubella, and the highly infectious nature of these diseases, high vaccination coverage is essential. The diseases that the vaccines are preventing are not benign and vaccination can eliminate many of the serious sequelae of these infections.”
Overall, the article’s conclusions are erroneous and misleading, driven by flawed logic and omission of relevant facts.
- 1 – Varun K. Phadke (2016) Association Between Vaccine Refusal and Vaccine-Preventable Diseases in the United States – A Review of Measles and Pertussis. Journal of the American Medical Association
- 2 – Ljungman. (2012) Vaccination of immunocompromised patients. Clinical Microbiology and Infection.
- 3 – De Serres et al. (2013) Largest measles epidemic in North America in a decade–Quebec, Canada, 2011: contribution of susceptibility, serendipity, and superspreading events. Journal of Infectious Diseases.
- 4 – Wiedermann et al. (2016) Primary vaccine failure to routine vaccines: Why and what to do? Human Vaccines And Immunotherapeutics.
- 5 – Wong et al. (2019) The impact of measles immunization campaigns in India using a nationally representative sample of 27,000 child deaths. eLife.
- 6 – Wilson et al. (2011) Adverse events following 12 and 18 month vaccinations: a population-based, self-controlled case series analysis. PLoSOne.
UPDATE 17 May 2019
The article has been updated to clarify that the Collective Evolution article reported the incorrect claim that was originally made by Tetyana Obukhanych while ignoring evidence that contradicts the claim.