vaccines medicine immunology disease pathogens immune system

The scientific facts behind the safety and efficacy of childhood vaccines

Calling the Shots - Discussing Vaccines

You’ve probably encountered memes, celebrities, and blogs vilifying childhood vaccines - let’s dive into some facts that will hopefully help clarify just how safe and effective the science community agrees vaccines to be.

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Fig 1: White blood cells which are cells of the immune system (large purple stained cells) along with red blood cells (small pink cells). Source.

The human body is a phenomenal machine and the immune system is astonishingly sophisticated. Almost as remarkable, is the idea that we can tap into the immune system’s ability to remember. This is how vaccines work. We introduce to the body only a component of a certain pathogen (a disease causing agent) – such as a protein that coats a virus, tricking the immune system into thinking that it is under attack by that pathogen. In response, it builds an army of antibody producing cells called B cells. Some of these cells, called memory B cells, much like an elephant, will never forget. If the same pathogen comes a-knocking, the immune system will be ready with specific antibodies to fight off the infection quickly. Is that not the coolest thing you’ve heard this week?! We take advantage of the immune system’s memory to make sure it’s prepared to fight certain infections. So, what’s all the fuss about vaccines? Why would anyone opt out of preventing a nasty and potentially deadly disease?

Vaccines and Autism

The story of the current anti-vaxxer movement begins with the medical doctor and researcher Andrew Wakefield. In 1998 Wakefield published a paper claiming that the MMR (Measles Mumps Rubella) vaccine caused autism in children. For a scientific discovery to hold true, the data supporting it must be reproducible, and fortunately with such an impactful discovery, researchers rushed to further investigate Wakefield’s findings. As the data proved unreproducible, the scientific community called shenanigans on the study and Wakefield was found guilty of deliberate fraud. The paper was immediately retracted and to this day he cannot practice medicine [1]. But why would someone want to scare parents away from vaccines, possibly resulting in the death of innocent children? The answer, as you probably guessed, was money. It turned out that Wakefield had developed a patent for a “safer” Measles vaccine just the previous year [2]. Conflict of interest, anyone? As if that wasn’t enough, Wakefield was also involved in a lawsuit against MMR vaccine manufacturers and was paid by lawyers while publishing his falsified data [3].

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Fig 2 Source


With the autism connection being bogus, what else could make a parent think their child is better off unvaccinated? Concerns regarding toxins found in vaccines seem quite common, including concerns about formaldehyde. Do you know where you can find formaldehyde? In pears. Do you know where else? Naturally occurring in our body as part of normal metabolism. In fact, the amount found in vaccines is lower than the amount found in a pear and the amount found in a healthy human [4]. Another toxin that comes up is mercury, whose presence in childhood vaccines is simply factually incorrect as it was removed from all childhood vaccines back in 2001 [5].

Do vaccines even work?

To answer this, let’s consider epidemiological observations: A diphtheria outbreak in the former Soviet Union took the lives of 4,000 individuals in 5 years [6]. Coincidentally, the outbreak occurred right after the collapse of the Soviet Union, which resulted in the obstruction of childhood vaccination programs.

Here’s another example: India used to have the highest rate of paralytic polio cases in the world. Interestingly, the number of cases dropped as the vaccination program coverage became more widely spread [7]. India has been polio free since geographical coverage reached a maximum [8]. The Measles vaccine has taken us from 2.6 million deaths caused by Measles per year to 114,000 with a vaccination rate of 85% of children in the world [9]. And finally, a pertussis outbreak in California has so far killed 10 infants and young children in unvaccinated communities [10]. Based on these examples, does it sound to you like vaccination works to prevent disease?

image alt text Fig 3: A microscopic image of Bordetella pertussis, the bacterium that causes the disease pertussis. Source

How to Identify B.S.

While it might be the parents’ decision whether or not to vaccinate, it is crucial to know the facts before deciding. As the biochemist Linus Pauling said: “Facts are the air of scientists. Without them you can never fly” and it is important to remember that science is out to find facts and therefore its only agenda is (or at least should be) finding the truth. That is why for sensible healthy decisions, we should look to scientific data and not uninformed propaganda. Critical thinking is crucial when assessing the validity of information circulating in social media, as it can be misleading. For example, when trying to understand risk of a disease look out for the terms morbidity vs. mortality – just because the number of patients dying has dropped, does not mean that there are less people getting sick. Or when looking at timelines of disease prevalence, be aware of developments such as booster shots or a vaccine being added to routine vaccination as compared to just introduced.

Before the invention of vaccines, one third of a family’s children would not make it past the age of 5. While that number also has to do with other medical advances and hygiene, vaccines are still one of the most significant health related breakthroughs in human history and have saved millions of lives. We owe it to ourselves, our children, and our communities to question their demonization.


[1] RETRACTED: Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children Wakefield, AJ et al. The Lancet , Volume 351 , Issue 9103 , 637 – 641

[2] Deer, B. “Revealed: Wakefield’s Secret First MMR Patent Claims “safer Measles Vaccine”” Brian Deer Investigates MMR. 2004. Poi:

[3] Rao, T. S. S., and Andrade, C. (2011). The MMR vaccine and autism: Sensation, refutation, retraction, and fraud. Indian Journal of Psychiatry, 53(2), 95–96.

[4] Mitkusa, R. J., Hess, M. A., and Schwartz, S. L. (2013). “U.S. Food and Drug Administration.” FDA Study Reinforces No Safety Concerns from Residual Formaldehyde in Some Infant Vaccines. U.S. FDA Center for Biologics Evaluation and Research.

[5] “Frequently Asked Questions about Thimerosal.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention. (2015)

[6] Vitek, C. R., and Wharton, M. (1998) “Diphtheria in the Former Soviet Union: Reemergence of a Pandemic Disease” - Volume 4 Emerging Infectious Disease Journal - CDC. Centers for Disease Control and Prevention.

[7] Bahl, S. et al. (2014). “Polio-Free Certification and Lessons Learned — South-East Asia Region. Centers for Disease Control and Prevention.

[8] “Progress Toward Poliomyelitis Eradication - India January 2007-May 2009.” (2009). Centers for Disease Control and Prevention.

[9] Measles Report. (2016). World Health Organization. N.p., (2016).

[10] Poland GA, Jacobson RM. (2011). The age-old struggle against the antivaccinationists.

N Engl J Med. 2011;364(2):97–9

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