Brief Vaccine Q and A

[Note: This was original a post on my page on February 9, 2019. It has undergone some revisions for clarity, as well as continues to grow–which is why you might see some citations numbered out of order]

Welcome aboard. Have questions? So did I.

Years before I became a parent, before I became a science major in college, and long before I worked in any lab and went to grad school, I had some concerns about vaccines. I had PLENTY of shots in the Marine Corps. But what about kids? Were they given too many vaccines for diseases long gone?

Some of the anti-vaccine rhetoric made sense to me, or at least it appeared so at first. I was going to be a parent soon, and I was concerned about potential toxins. But then I met our professor, a Polio survivor who contracted the disease just before the vaccine was made readily available. He barely survived the infection and needed mobility aides due to a limp. I educated myself, learned the science, and my fears were abated.

After my first born, I later had two more professors, whom each worked in immunology. I learned even more, and in the small ways I could, helped advocate vaccine safety.

On my Facebook page, I was asked to weigh in on some questions about vaccines. My responses below only scratch the surface of immunology (the study of the immune system), vaccines, and epidemiology (the study of how diseases spread in populations). But as you can see, for a Facebook post, this provides more than enough information to get you started. Hell, it might even be overkill, but that is how I roll.

As a scientific scholar, I must disclose that immunology, virology, and epidemiology a are not my specific areas of study, but neither am I unfamiliar with them. I am more than reasonably confident the information and resources provided are accurate. This article here is not THE evidence on vaccines, but is instead a communication of the evidence. Still, if any experts in these fields can help clarify/ expound/ correct/ expand this information, then your commentary would be most welcome! I am not (nor should I be) *THE* authority on this. Please see the CDC for more information, and as always, talk to your doctor about your specific needs.

Scientific data is great, but I am a people person, not a data person. Can you help with the more personal, human side?”

Absolutely. If you want some stories before learning the evidence , I totally understand, and applaud you. Stories are not evidence, but they can help highlight the meaning and importance of the evidence on a human perspective.

“Are there personal accounts on the importance of vaccines?

Yup! Below are a couple of videos from the first link.

The link above has plenty of other videos and written stories if you want. The linksbelwo offer some written accounts.

The stories are diverse. Many people are born with a compromised immune system and cant receive vaccines; many cancer patients (especially young children with developing immune systems) are at risk for diseases; and some parents have lost young children from preventable diseases do to their decision to not vaccinate, or their child was too young for a vaccine and got infected from someone else. Vaccines save precious lives.

Are there personal accounts of vaccine-hesitant parents who changed there mind?”

There sure are. Here are just a few.

One excerpt from the second link reads:

“In the summer of 2014, I was in one particular anti-vaxxer Facebook group, and there was a debate going on about vaccines, and I started to notice that every time someone disagreed with them, the core members got belligerent, going straight to personal attacks. I also noticed that every single point they brought up had this immense conspiracy to go along with it. By that point, I’d started to think, “Do I really believe in all these conspiracies? Am I really that afraid, or can I go back and look at the evidence again?” By then, my daughter was 8 months old, and I just got over the fear I had as a first-time mom. I realized that my daughter was going to be OK.”

“What are the origins of the anti-vaccine movement?”

I got your six. Much of this movement got its start with Dr. Andrew Wakefield’s paper that associated vaccines with autism. His sample size was 12, and he and his co-authors still reported fraudulent data, and lost his license (25).

Here are couple of videos

“Thanks for the human side of things. I have some questions on the science.”

“How do vaccines work?”

Great question. Below are three short videos that can get you started.

“I have some questions on vaccine research…”

No problem, below are some answers to common questions.


True, much of the medical industry is profit-oriented, to include pharmaceuticals. But the profits for developing and selling vaccines that prevent disease is minuscule compared to drugs. In fact, many businesses stopped making vaccines because the profits are too low. More.


No research has confirmed a link between vaccines and neurodegenerative disorders [1]. During the late 1990s, there was a public concern that the Hepatitis B vaccine may have caused a few cases of MS. This potential link was researched, and no causal relationship was found [2, 3]. No link has been discovered between vaccines and autism. It is woefully unlikely there even is one. But, this link was seriously researched in numerous studies and meta-studies, several of which were large scale [4-8].


Indeed, rates of autism are increasing. But this is mostly a result of advances in screening methods and screening becoming more common (however, testing needs to be improved for impoverished children) [9, 10]. Though screening methods explains a large portion of the increase in autism rates, researchers are still investigating if this explains *all* of it. Science is not dogmatic ideology; it is a systematic mode of inquiry that constantly reexamines ideas, refining the understanding as new information comes to light—especially in pertinent matters such as human health. So yes, some supplemental hypotheses have been proposed to help explain a portion of the rising autism trends. One intriguing (yet to be demonstrated) example includes the *potential* release of trace amounts of mercury from dental amalgam fillings in expecting mothers after being exposed to electromagnetic fields. The idea is that this trace amount (if even true) may be enough to affect a developing fetus. BUT—and I cannot stress this enough—the researchers emphasize this is merely a working hypothesis that *might* explain some of the rising rates of autism. Nothing about this potential hypothesis is remotely conclusive, and it is limited to only developing fetuses and not to older children and adults with dental amalgam fillings. (It also needs to demonstrate the release of harmful mercury that can bioaccumulate, which is something I discuss in the ‘mercury’ section of this post). Later research may provide clearer insight [11]. I merely point this out to demonstrate that there are aspects of autism research still ongoing. So for now, talk to your dentist if you have any concerns.


In very rare instances (often, less than 1 out of 100,000), a person may be allergic to one or more components (i.e., ingredients) of a vaccine [12-15]. Some mild adverse reactions to a vaccine ingredient can occur, but these are at least somewhat rare [14, 16]. There are immunocompromised people (meaning their immune systems are in some capacity dysfunctional) who cannot receive vaccines for safety reasons. Guidelines are in place for their care [17]. However, these people primarily rely on herd immunity—where the general population is vaccinated above a critical threshold. If the percentage of people in the community are immunized above this threshold, then the chances for a massive outbreak substantially decline. Conversely, if the portion of the population that is vaccinated is below this threshold, then the odds for an outbreak increases. This threshold is a complex calculation that varies on how infectious the disease is, the effectiveness of the vaccine, population density, etc.. [the threshold is often a percentage in the 90s, see the CDC for more]. But herd immunity is critical for another reason too: the more a disease reproduces in an infected person, the more chances it can develop a mutation that renders the vaccine ineffective, and/or obtain a mutation that makes the virus even deadlier. The exact mechanisms that lead to these adverse reactions may vary from person to person, and in many instances, the supporting evidence for these adverse reactions is only anecdotal (i.e. personal recollection). But some potential reasons may be that they are 1) a random infection prior to receiving the vaccine, or before the vaccine takes effect, which can take several days or even a few weeks. (For example, people get the flu shot *during* the flu season). Other causes may include: 2) needle anxiety, 3) hyperimmune response from being physically punctured, 4) manufacturing error, 5) mishandling by the healthcare worker, nurse, doctor, et cetera [18].


A form of mercury used to be used in some vaccines, but this practice in childhood vaccines stopped in the US in 2001 due to public concern (see the CDC), rather than medical/scientific concerns. The properties of mercury, like every other chemical, depends on its exact composition. Methyl mercury is the kind that bioaccumulates in ecosystems and stays in organisms for extended periods (posing a risk). Thimerosal contained ethylmercury, which has vastly different properties. It was a useful additive to help preserve the integrity and efficacy of the vaccines. But because other additives can do the same job without mercury, thimerosal was abandoned in favor of more publicly favored additives. Ethyl mercury is regarded as safe because it leaves organisms swiftly, (i.e., ethylmercury does not accumulate and affect the body like methylmercury). Chemistry makes all the difference. A common analogous trope shared on social media is that sodium and chloride themselves are dangerous chemicals. But combined together, sodium chloride is merely table salt. These properties of different forms of mercury have been understood for a long time and were extensively studied after public concerns over rising mercury levels were observed in fish [19]. Moreover, the amount of thimerosal in each dose was minute, and it’s the dose (over time per unit of body mass) varied by route exposure, (and other factors) that makes the poison. [See the CDC].


Vaccines contain small doses of adjuvants (organic or inorganic substances that help’s immune system develop a stronger immunity), stabilizers (which preserve the shelf life of the vaccine while it transported and stored), and as is often the case with vaccines from vials, preservatives (which kill germs if they accidently get introduced into the vial between uses). See the CDC for more about these. As explained above, dose over time per unit of body mass, route of exposure, and other factors determine toxicity. To put the importance of dose in perspective, apples contain 1-4 milligrams of amygdalin in their seeds. Amygdalin is a sugar-cyanide hybrid molecule (having both sugar and cyanide, however this varies greatly on apple type (23). The reported acute reference dose (the amount it takes for there to be risks in one exposure) can vary, but one recent study measured it as 0.075 mg of cyanide per of kg body weight (24). To put this in perspective, depending on your weight and apple type, you would have to eat somewhere between 150 and several thousand crushed seeds in one sitting before there was a risk for poisoning. Yeah, the number isn’t exact, but the point is you would need to eat shit-ton of apples because the dose is so minor. Similarly, those small doses in vaccines are not a threat, as also evidence by those large scale studies mentioned above.


For most people, the standard vaccine schedule is safe. One recent, large study found no association between vaccines and non-targeted infections in young children (26). And this should make sense. The amount of antigens or attenuated bacteria in a vaccine are minuscule compared to the number of germs that enter children (and adults) bodies from normal activities. But, talk to your doctor about vaccine schedules, especially if your child has medical complications.


This has been the subject of many studies, and parents have cited many reasons (See [20] for one such review). In no small part, vaccines are victims of their own success. It has been suggested that people are not vaccinated in part because they no longer see the diseases (or know of anybody with the diseases). So they don’t view the disease as a threat and transfer their fear to something they do see: vaccines and autism. Indeed, qualitative research supports this idea [21]. Moreover, the same holds true for general trust in doctors and social media influence. If one distrusts doctors, and/or is associated with anti-vaxx social circles (perpetuated by talking heads), they are less likely to vaccinate [21]. This phenomenon may be partially due to the Fuzzy-trace theory, which states (in very simplified terms) a lack of knowledge (in this case due to several conflicting voices) leads one to maintain a status quo and not take preventative action [22]. However, this too only scratches the surface.


This infographic does a decent job of explaining the basic idea of herd immunity.

But what about threshold values? Why is it recommend that roughly 82 to 94% of the population get vaccinated to develop herd immunity for measles? This video below explains the relationship between how fast a disease spreads and this threshold.


Two reasons: 1) No vaccine is 100% perfect. For example, the measles vaccine is about 98% effective (when used as directed). For whatever reason, some people just don’t develop the immunity after getting the vaccine. 2) Bayesian stats (i.e. background rate); the number of people who get vaccinated greatly outnumber the minority of those who do not vaccinate. So given how a disease spreads in a community (see the video above), the small chance of making a vaccinated person can be greater than infecting a non-vaccinated person. Of course, this depends on the R0, vaccination rates, and vaccine effectiveness). For more see:…/immunization…/en/index2.html

What this does not mean: herd immunity is perfect or vaccines don’t work.

What this does mean: even with herd immunity, it is common to see some people get sick. But “some people” is much better than “many people”–especially because hospitals can only treat a limited number of cases.

I saw a video of debate between pro-vaccine and anti-vaccine folks. What do doctors think.

As you read above, the evidence is overwhelmingly shows vaccines are safe and effective. But I get it. I am not a doctor, and you want some expert views based on evidence. Kudos! Like I said, I am not THE authority on this. But to help, here is a video of a doctor who reviewed that video.

No, vaccines are not Great Money Makers for the Health Industry

Hard-line anti-vax talking heads often accuse us science communicators of being shills protecting the health industry’s huge profits in vaccines. It doesn’t even make sense. The profit margin for vaccines are minuscule compared to the treatment of diseases. A vaccine might a few dozen dollars for a patient. In contrast, treatment can cost several thousand. According to the CDC, these are the typical hospitalization costs for treating various vaccine-preventable diseases.

Moreover, these diseases have been nearly eradicated after enough people were vaccinated. Look at these rates (per 100,000) before the population was vaccinated and after:

Clearly, the greater profit is in withholding vaccines and treating these diseases. Giving vaccines literally reduces the potential revenue for the health industry.

That was a lot. What are the big takeaways?

Unless you have a rare condition, vaccines are safe, and they save lives. Herd immunity is essential to limit the chances of a massive outbreak. No known diseases or conditions are linked with vaccines. Autism rates are rising because of better testing, but research is still ongoing about other possibilities. No, toxic mercury was not used in vaccines, and the practice of using thimerosal has been abandoned.

Carpe Datum and Semper Sci!

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1. Gasparini, R., et al., The “urban myth” of the association between neurological disorders and vaccinations. Journal of preventive medicine and hygiene, 2015. 56(1): p. E1-E8.

2. Ascherio, A., et al., Hepatitis B Vaccination and the Risk of Multiple Sclerosis. New England Journal of Medicine, 2001. 344(5): p. 327-332.

3. Stratton K, Almario D, and M.M. (editors), Immunization Safety Review: Hepatitis B Vaccine and Demyelinating Neurological Disorders., I.o.M.U.I.S.R. Committee;, Editor. 2002: Washington DC.

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9. Arunyanart, W., et al., Developmental and Autism Screening: A Survey Across Six States. Infants & Young Children, 2012. 25(3): p. 175-187.

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11. Mortazavi, G., et al., Increased Release of Mercury from Dental Amalgam Fillings due to Maternal Exposure to Electromagnetic Fields as a Possible Mechanism for the High Rates of Autism in the Offspring: Introducing a Hypothesis. Journal of biomedical physics & engineering, 2016. 6(1): p. 41-46.

12. Bohlke, K., et al., Risk of anaphylaxis after vaccination of children and adolescents. Pediatrics, 2003. 112(4): p. 815-20.

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14. Wood, R.A., et al., An Algorithm for Treatment of Patients With Hypersensitivity Reactions After Vaccines. Pediatrics, 2008. 122(3): p. e771-e777.

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16. Zhou, W., et al., Surveillance for Safety After Immunization: Vaccine Adverse Event Reporting System (VAERS) — United States, 1991–2001, CDC, Editor. 2003.

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20. McKee, C. and K. Bohannon, Exploring the Reasons Behind Parental Refusal of Vaccines. The journal of pediatric pharmacology and therapeutics : JPPT : the official journal of PPAG, 2016. 21(2): p. 104-109.

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22. Reyna, V.F., Risk perception and communication in vaccination decisions: A fuzzy-trace theory approach. Vaccine, 2012. 30(25): p. 3790-3797.

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24. Abraham, K., Buhrke, T., & Lampen, A . Bioavailability of cyanide after consumption of a single meal of foods containing high levels of cyanogenic glycosides: a crossover study in humans. Archives of toxicology, 2012. 90(3),p. 559–574.

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