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Monday, October 7, 2019

Vaccines, the Internet, and trust of science

Demonizing anti-vaxxers will only reduce the public's trust in science. Here's how that works.


V accination against infectious diseases like polio, smallpox and rubella has been spectacularly successful in reducing their incidence. However, the current campaign to demonize anti-vaxxers is counterproductive. It turns the dialogue away from science to politics and name-calling, which causes the reliability of information to drop precipitously. Experts lose interest in the topic, laymen become confused, and those who question the official dogma lose faith in the scientific and medical establishments.

The free rider problem

There is much discussion about irrational fear of vaccinations, but free riders are more dangerous. A free rider is a person who benefits from the immunity of others but doesn't get vaccinated. The free rider encourages everyone else to get vaccinated and reaps the benefits. He or she is thus highly motivated to conceal knowledge of the vaccine's risks. This in turn causes others to suspect that the danger is greater than commonly believed.

Falsely minimizing the dangers or ridiculing skeptics is dangerous because skeptics will assume that the entire program is corrupt. They may conclude that the risks must be very high indeed if the only way to gain compliance is by deception and force.

Distrust in science

While researching this topic, I ran across a recent (2018) article in Scientific American titled “Distrust in Science” that had me choking on my corn flakes.

The author cites a 2014 poll showing that only 14% of those surveyed had a “great deal of confidence” in academia. He blames bloggers, claiming that the Internet (which competes with his print magazine) is full of misleading information. But the real cause may be the relentless politicization by academics of nearly every topic, from hiring practices to research in formerly placid branches of science like nutrition and climate. Ironically, it is print magazines like Lancet, Nature, and especially Scientific American, that have played the biggest role in politicizing science.

It was Lancet, not some stain-shirted, Cheeto dust-covered blogger, that published a politically charged report during the First Iraq War grossly inflating the number of civilian casualties by counting people who didn't get conceived during the conflict. It was Lancet that published Andrew Wakefield's 1998 paper falsely claiming that MMR (measles, mumps, and rubella) vaccine caused autism. This claim is, of course, not true: massive research, culminating in an enormous meta-analysis in 2014 Vaccine involving nearly 1.3 million people, found no evidence for such an effect.

It is also false to claim, as the author did, that it is “incredibly rare” for a “scientific consensus” to be wrong. One need only look at the 180 degree turn that nutritionists have been forced to make about cholesterol for an example. Regrettably, activists often use the term ‘consensus’ to falsely assert that science backs up their ideologically based claims.

Finally, he says “most people can't tell the difference between truth and falsehood online.” The citation for this is, ironically, to an online article which discussed a 2016 report claiming that young people are easily duped by Google and social media, and which gripes about the little blighters not under­standing the significance of a blue checkmark in Twitter. His solution is to “curate” the Internet via “reputational awards” to be awarded by a “crowdsourced reporting and evaluation mechanism.”

A better solution would be to make medical articles more easily available to the public. Even science professionals often can't access important articles because of the cost. Academics can use interlibrary loan—but how can they criticize people for not knowing information members of the public are unable to access? The NIH's Public Access Policy, which gave us Pubmed Central, is a great start, but still far too limited.

Truth thrives only when all opinions can be heard and evaluated. Censoring ideas that violate the herd consensus, as Scientific American recommends, creates mistrust.

Anyway . . . getting back to vaccines . . . where was I?

Risks of vaccines

It would be disingenuous to claim that vaccinations are completely without risks. However, the risks of being vaccinated must be compared to the risk from catching the disease itself.

Here are the main fears reported by anti-vaxxers.

Thiomersal (aka thimerosal) is a compound containing mercury chemically bonded to a thiol compound. It is metabolized in the body to ethylmercury, which is highly toxic. However, its use in childhood vaccines was stopped by 2001, and even before that it would have been very difficult to get mercury poisoning from the small amounts in a vaccine.[1]

Autism As discussed above, the single paper by Andrew Wakefield in Lancet claiming that MMR vaccine caused autism, widely believed by anti-vaxxers, was found by the UK General Medical Council to contain deliberate falsifications. As of 2019, the causes of autism are unknown. There is no evidence that any vaccines cause autism.

Neurological autoimmune disorders Some vaccines have caused autoimmune disorders. However, viral diseases can cause the same disorders, and vaccines often get the blame for what the virus actually did. The four big ones are:

According to Julia Stowe, writing in the October 1 2019 issue of CNS Drugs[3], GBS and narcolepsy are the greatest concern with influenza vaccination. The risk of GBS from vaccination, while not zero, is considerably lower than the risk from influenza itself, which carries a 7-fold increased risk of GBS in unvaccinated patients. On the rare occasions when a patient contracted GBS after being vaccinated, it almost always fell outside the six-week window that would implicate vaccination. This means it was almost certainly caused by a viral infection, not the vaccine.

The authors write:

Rapid investigation of vaccine safety concerns, however biologically implausible, is essential to maintain public and professional confidence in vaccination programmes.

This is an important point. We must recognize that fear of vaccines is a fully rational response. Ridiculing anti-vaxxers will not change their minds. It will only convince them that there is indeed a conspiracy to conceal vital information from them.

The suspicion that information about risks is being suppressed or falsified is really a suspicion that others are using motivated reasoning, i.e. that they have an ulterior motive. This suspicion is enhanced when emotional appeals, threats of forced unemployment, name-calling, or ridicule are used to gain compliance.

Leaflet dropped by US Air force
An article from Frontiers in Immunology found in my back yard last week after a C-130 flew overhead
Unfortunately, it's hard to calculate a risk/benefit ratio because the risks vary among different vaccines. One vaccine, the Pandemrix® influenza vaccine, which was used against H1N1 influenza A in Europe in 2009, reportedly carried a 13-fold increased risk of narcolepsy, or about one in 18,400 vaccine doses, while the risks from other vaccines against the same strain were so low they were undetectable in the statistical noise.[3] H1N1 influenza infection also increases the risk of narcolepsy in unvaccinated patients.[4] Each individual has the responsibility to investigate the facts—and medical publishers have a responsibility to make sure this critical health information is freely accessible.

It's true, of course, that the “natural” community produces vast quantities of paranoid anti-scientific nonsense. Just last Friday one article came out claiming that vaccines contain human DNA that has been genetically modified to cause cancer in vaccine recipients. Any trained biologist would read this with open-mouthed shock that someone could write something so idiotic. It would be rejected by any publisher of sci-fi paperbacks. However, this is all the more reason we must provide accurate information—by dropping scientific reprints from a B-17 if necessary—to those in need.

Herd immunity

Enough of that boring stuff. Let's get to the math!

The concept of herd immunity says that if about 95% of the population is immune, a disease will not spread. This is, of course, a vast oversimplification. Entire books, full of complicated equations, have been written on this subject, but a simple model for herd immunity is the formula

Vc = qc / E

where

Vc is vaccine coverage as a fraction of the population.

qc = 1 − 1/R0 is the critical immunization threshold, that is the fraction of the population needed to make R0 less than 1

R0 is a measure of how transmittable the disease is. It's defined as the average number of people that a single infectious person will potentially infect. R0 must be above 1 for the disease to spread. It is different for each disease. For measles, it is 12. For influenza, it is 1.5–1.8.

E is the efficacy of the vaccine (0 to 1).

All vaccines are not alike. Polio, measles, and rubella vaccines are highly effective. Influenza vaccines typically are much less—usually 40–60% if the strain matches the vaccine, 10% or less if not.

From the above formula, it's easy to calculate that the effectiveness of an influenza vaccine has to be greater than 33–44% to achieve full herd immunity, assuming 100% vaccination. If it's less effective than that, it's impossible to stop the spread completely, but it can still reduce it.


1. Offit PA, Jew RK. (2003). Addressing parents' concerns: do vaccines contain harmful preservatives, adjuvants, additives, or residuals? Pediatrics. 112(6 Pt 1), 1394–1397. PMID: 14654615 DOI: 10.1542/peds.112.6.1394 Full text link

2. Goldman AS, Schmalstieg EJ, Dreyer CF, Schmalstieg FC Jr, Goldman DA (2016). Franklin Delano Roosevelt's (FDR's) (1882-1945) 1921 neurological disease revisited; the most likely diagnosis remains Guillain-Barré syndrome. J Med Biogr. 24(4), 452–459. PMID: 26508622 DOI: 10.1177/0967772015605738 Link

3. Stowe J, Andrews N, Miller E. (2019). Do Vaccines Trigger Neurological Diseases? Epidemiological Evaluation of Vaccination and Neurological Diseases Using Examples of Multiple Sclerosis, Guillain-Barré Syndrome and Narcolepsy. CNS Drugs. Oct 1. doi: 10.1007/s40263-019-00670-y. PMID: 31576507 Link

4. Bonvalet M, Ollila HM, Ambati A, Mignot E. (2017). Autoimmunity in narcolepsy. Curr Opin Pulm Med. 23(6), 522–529. doi: 10.1097/MCP.0000000000000426. PMID: 28991006 PMCID: PMC5773260 Link


oct 07 2019, 5:02 am. edited oct 08 2018, 5:00 pm


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