In the two decades following Wakefield’s paper, a number of other credible-seeming people have become well known for promoting anti-vaccine views. Some of them have been notable enough to warrant discussion.
In 2007 pediatrician Dr. Robert Sears, “Dr. Bob,” published The Vaccine Book: Making the Right Decision for Your Child. In it he falls short of recommending against vaccination altogether. The book offers two schedules: one that delays receiving some vaccines, “Dr Bob’s Alternative Vaccine Schedule,” and another that recommends receiving only vaccines that Sears considers to be important.1
The book makes a number of spurious and false claims and reaches its conclusions through faulty logic. The primary problem with the reasoning of The Vaccine Book is the approach it takes to safety. The way that scientists evaluate safety is complex, but it’s usually assumed in science that phenomena we look for aren’t going to exist. With medicine there’s a precautionary principle that medicines should be tested before use, just in case they cause an adverse reaction. However, The Vaccine Book starts with the opposite assumption—that danger may exist and that until it is tested to Dr. Bob’s satisfaction, it should be assumed to exist, and even after it has been tested beyond all reasonable suspicion, it should still be assumed to exist.
Dr. Bob is the son of William Sears, “Dr. Will,” creator of the Sears parenting library, which includes a number of books: The Baby Book (1993), The Pregnancy Book (1997), and The Complete Book of Christian Parenting and Child Care: A Medical and Moral Guide to Raising Happy Healthy Children (1997). Dr. Will is also a media personality who has appeared on many talk shows, including The Oprah Winfrey Show and Good Morning America. Three of Dr. Will’s children have become physicians. One, Jim Sears, is a television personality on The Doctors, a spin-off of the Dr. Phil show, produced by Del Bigtree. Given the branding of The Vaccine Book and the Sears name, Robert Sears’s contribution to the family business is easy to confuse with his father’s.
Sears may object to being included in the same category as those who are actively anti-vaccine, since The Vaccine Book stops short of recommending against vaccination altogether. However, the book is dangerous in a subtler way. It borrows arguments from the anti-vaccine movement and, rather than pointing parents to good literature and the body of scientific work related to vaccines, lends those arguments the credibility of a friendly faced physician and promotes an “alternative” schedule with serious downsides and no upsides. It allows parents to feel as though they’ve made a rational, well-researched choice (not like those anti-vaccine people).
One vaccine ingredient Robert Sears focuses on is aluminum. Aluminum-containing molecules, usually alum, are used in vaccines as adjuvants. An adjuvant is something included in a vaccine that enhances the response of the immune system. Alum was first tested in the early 1920s to work with a diphtheria-toxin vaccine.2
Our understanding of precisely how alum enhances the immune response in vaccines is still evolving.3 One hypothesis is known as depot formation. Researchers took skin where guinea pigs had been injected with either diphtheria toxin that was precipitated (made insoluble) or diphtheria toxoid (DT) that was soluble. This skin was homogenized (blended, basically) and injected into a new set of guinea pigs. In the newly injected guinea pigs, those injected with the skin from alum-precipitated DT became immune, but those injected with the skin from soluble-DT–injected guinea pigs did not. This led the researchers to hypothesize that the alum-precipitated DT was eliminated less quickly and that the sustained immune response is what caused immunity.4 In this model, alum holds on to antigens in the tissue and slowly releases them. This hypothesis is not universally accepted. Others have hypothesized that injected alum recruits antigen-presenting cells, which can then trigger subsequent steps in the adaptive immune response,5 or that alum helps antigen-loaded antigen-presenting cells to migrate to lymphoid tissues.
Regardless of the precise mechanism, or mechanisms, of action, we now have over 90 years of empirical data regarding the use of aluminum-containing compounds in vaccines. Empirically we know that it works and is safe. Specifically, the safety of each vaccine that contains aluminum (or any other ingredient) is heavily tested before being approved. The amount of aluminum per dose of vaccine in the United States is about 0.85 to 0.125 mg/dose.6
Sears’s concern was that the aluminum in vaccines received by a child following the CDC-recommended vaccination schedule might accumulate and cause a greater effect than that from the individual doses. However, the safety profile of aluminum has been well established over decades of testing. Furthermore, there is already environmental exposure to some amounts of aluminum without ill effect. There is a small amount of aluminum present in breast milk,7 and infant formulas contain significant amounts of aluminum.8 Indeed the amount of aluminum in a liter of formula is comparable to the amount present in a dose of vaccine. Infants on soy-based formula take in almost twenty times as much aluminum in food during their first six months than is injected through vaccines, yet infants are successfully able to clear the excess aluminum from soy formula.9 Sears’s dislike of aluminum is not based on evidence.
For an example of the negative effects of delaying a vaccine, experts recommend that flu shots begin at six months. Not only do flu shots reduce the rate of infection, they reduce the severity of flu. Those who are infected and become sick are less likely to die or be hospitalized.10 In 2017 in the United States there were over 80,000 flu deaths, including 180 babies, children, and teenagers.11 This is an unusually high number. Even during the 2009 flu pandemic, nearly 60,000,000 infections led to fewer deaths. Although the number of cases of flu that lead to infant death each year are low, hospitalizations of children with flu are rarely recognized and are in the tens of thousands each year.12 To take measles as another example, not only will children be vulnerable to infections with measles or hepatitis B, they will be able to pass measles to infant siblings, who are even more vulnerable to infection.
Sears’s recommendation to space out vaccines goes against the best practices developed by the profession and does nothing to improve safety. Spacing out office visits means more office visits, with Sears’s schedule requiring nineteen visits in the first five years of life. More office visits means lower likelihood of complete compliance, greater expense, and a higher workload for already overworked pediatricians, physician’s assistants, and nurses. Bear in mind that all these costs in risk of infection and death, increased expense, wasted time, and increased disease burden are intended to prevent a comparatively miniscule dose of aluminum from accumulating, despite Sears’s providing no plausible explanation for how it could or what harm he supposes it will cause. A tangible harm is being accepted to avoid an imagined risk.
Sears recommends against teenagers receiving the meningococcal conjugate vaccine. At the time The Vaccine Book was first written, concern had been raised from the Vaccine Adverse Event Reporting System due to five reports of Guillain-Barré syndrome shortly after receiving the vaccine. Guillain-Barré syndrome is a rare autoimmune disease. Autoimmune diseases occur when the immune system’s function of determining between things that belong in your body and things that don’t fails, so the immune system starts attacking tissues and cells that do belong. In the case of Guillain-Barré syndrome, the tissues being attacked are parts of the nervous system outside of the brain and spinal cord.13 The exact causes of Guillain-Barré syndrome aren’t known, so it’s hard to know which proposed causes are and are not true. It is known that certain viral infections can increase risk, and the 1976 flu vaccine has been suggested to have triggered an increased risk of Guillain-Barré syndrome.14 However, in 2012 two large and rather comprehensive cohort studies were conducted to determine if there was a link between the meningococcal conjugate vaccine and the development of Guillain-Barré syndrome. No such link was found to exist.15 This means that parents opting out of this vaccine are accepting a risk of disease for a null benefit.
Another claim made in The Vaccine Book is that children vaccinated with the Hib vaccine are at increased risk for the development of haemophilus influenzae B infection for a short period after inoculation. This suspected link was first proposed in the late 1980s after efficacy trials of early Hib vaccines were conducted. It was expected that after a single dose of vaccine, some percentage of those vaccinated would still develop a Hib infection. Studies were conducted at a number of sites, and the ability of the vaccine to protect against infection was highly variable. In Northern California, efficacy was estimated to be 68 percent based on 120,000 children;16 45 percent in a case-control study of children in day care;17 58 percent in a Minnesota-based case-control study;18 88 percent in Dallas County, Connecticut; and 81 percent in greater Pittsburgh.19 In addition, several of these studies suggested a possibility that risk may increase in the week following immunization.
Two hypotheses were put forward that might have explained the cluster of cases that occurred in the first week. The first hypothesis was that the vaccine was interacting with antibodies already present in the blood and thus decreasing the number of available antibodies. A second hypothesis was that vaccination shortened the incubation time of already-infected children so that they presented symptoms sooner, although they would have become sick regardless.
In support of his concern, Sears cited three papers. The first paper, published in 1986, did not reach the conclusion that he presents it as reaching. The study selected fifty-five cases of children who had received the Hib vaccine but still caught Hib and compared the levels of antibodies in their blood to those of children who had not been vaccinated and had developed Hib infection. In 33 of these children (compared to 331 control patients) levels of the antibody against Hib were low.20 The authors concluded that some genetic factors may be at play that caused the vaccine to fail in this case. This does not mean that the vaccine caused these children to be more prone to infection. The children in this study were already selected for the rare instance of the Hib vaccine’s failing to protect them from infection. This means that a far more likely explanation is that these children had low antibody levels because of some secondary (possibly genetic) factor, which is why the vaccine failed in their case. The control children were never vaccinated, so while a subpopulation may exist with the same underlying factor, that factor has not been selected for by the failure of the vaccine.
A second study examined the antibody levels in serum from children and adults for three days after inoculation with the Hib vaccine and seemed to show a 15 to 25 percent decrease in serum-antibody levels.21 However, seven days after immunization, detectable antibody levels rose again to above the pre-inoculation value. Another study from the same year suggested that antibody levels may be depressed only in those children who already had detectable levels of antibody before vaccination.22 Although a variety of studies suggested a possibility that there was a minor decrease in immunity for roughly seven days in children eighteen months or older who received the vaccine, the estimate of incidence with the vaccine was at most 1.6 cases/100,000, or likely lower, given the decreased prevalence of Hib in the post-vaccine era.23 Regardless, these studies looked only at the unconjugated Hib vaccine, which was marketed from 1985 to1988, and was withdrawn because it did not produce adequate immunity in children under eighteen months of age. The current forms of the Hib vaccine, which are conjugated to adjuvants, have never been associated with an increased risk of infection. Drawing the link between a vaccine that at the time of publication had not been marketed for nineteen years and the current Hib vaccines seems a strange way to discuss risk and serves only to create needless fear.
The Vaccine Book also repeats claims about mercury in thimerosal, as well as claims that MMR vaccine may be linked to autism. I address claims of this nature at length in other chapters. Other vaccine ingredients that bother Sears include fetal bovine serum (FBS). FBS is a product used in tissue culture that is derived from cow blood. FBS contains proteins and peptides that enhance the growth of cultured cells, causing them to thrive and divide more readily in the foreign environment of a plastic dish. Although scientists have considered several alternatives to FBS,24 they are reluctant to switch to these alternatives in many established protocols because they can change the behavior of cells. A cell line that behaves in a known and predictable way in one growth medium may behave in an unpredictable way in another medium. Sears, of course, does not attack the many other medicines that are produced similarly using mammalian-tissue culture and presumably using FBS.25
The primary reason cited for the concern was the possibility of mad cow disease26 being transmitted. Mad cow disease is thought to affect the nervous system of cows, causing unusual behavior, tremors, and eventually death. No one knows for sure what causes the disease at the molecular level, although it is associated with eating feed contaminated with tissue from affected animals. One well-supported hypothesis is that the disease is caused by something called a prion.
Proteins are chains of smaller molecules called amino acids. Each amino acid in a chain has distinct properties, and when amino acids are strung together by the subcellular structures known as ribosomes, they begin to fold. The three-dimensional structure of the final protein depends on the sequence of amino acids as well as the presence of other proteins, which help them take on the correct shape. So although the one-dimensional structure of a protein, also called its sequence, might be the same, there are multiple possible three-dimensional shapes it can take on. Prions are proteins that have taken on the wrong shape and cause other proteins of the same type to take on the same wrong shape. Eventually these misfolded proteins build up and cause cells to stop functioning as they should. The accumulation of misfolded proteins in the brain leads to disruptions in its functioning and is hypothesized in mad cow disease.
Mad cow disease can be transmitted to humans, although at that point we stop calling it mad cow disease and call it variant Creutzfeldt-Jakob disease (vCJD), from which a few more than two hundred people have suffered and for which there is no known cure. Ultimately, the disease results in death. Because vCJD can be transmitted by blood product,27 Sears’s concern is that the FBS used to maintain the cells that produce the live or killed virus for vaccines may be contaminated by vCJD-causing prions. Indeed, the possibly related Creutzfeldt-Jakob disease has been known to be transmitted by contaminated doses of human growth hormone derived from human cadavers in the past,28 although human growth hormone is no longer produced this way.
If there were an epidemic of mad cow disease in the United States, this might be a valid concern; however, there is no such epidemic. The United States has never suffered the kind of outbreak that Europe did, and Americans consume about 120 kg of meat each year,29 second only to the United Kingdom at about 136 kilograms per person per year. Often some of this meat comes from multiple cows, yet only four cases of vCJD have been reported in the United States, all people who had lived outside of the United States.30 If there were a widespread problem with vCJD’s being spread, it would have developed through contaminated meat. (Cooking meat does not seem to prevent the spread of the disease.)
In the United States, there are recommended schedules for immunization between birth and the age of eighteen. Many workplaces and educational institutions have immunization requirements as conditions of employment and enrollment to protect their employees and students. The first recommended vaccine is for HepB at birth, followed by an additional dose after one to two months. Then, at two months, vaccines for DTaP, Hib, pneumococcal conjugate, and polio, with second doses at four months, should be given. At six months, annual vaccinations against influenza should begin (infants and the elderly are at highest risk). And, at a year, the MMR, chickenpox, and HepA vaccines should be initiated.31
These recommendations are considered by the Advisory Committee on Immunization Practices, which considers several factors. These factors include safety at a given age, the severity of the disease prevented by the vaccine, the infection rate in an unvaccinated population, and potential complications that might arise from application of the vaccine. The recommendations are then set by the CDC, with approval by the American Academy of Pediatrics, American Academy of Family Physicians, and the American College of Obstetricians and Gynecologists.32 Sears goes against these recommendations on the basis of conjecture and misinterpretation of the literature.
The Vaccine Book takes great pains to appear reasonable, while muddying the water with scientific-sounding concerns that can be difficult to tease out for those without the time to seek primary sources and examine methods and conclusions carefully. Still, even some vaccine advocates will compromise by blithely saying, “It’s okay to delay!,” although there’s no reason to delay and doing so carries serious risks.
1. P. A. Offit and C. A. Moser, “The Problem with Dr Bob’s Alternative Vaccine Schedule,” Pediatrics 123 (2009): e164–e169.
2. A. T. Glenny and H. J. Südmersen, “Notes on the Production of Immunity to Diphtheria Toxin,” Journal of Hygiene 20 (1921): 176–220.
3. T. R. Ghimire, “The Mechanisms of Action of Vaccines Containing Aluminum Adjuvants: An In Vitro vs. In Vivo Paradigm,” Springerplus 4 (2015): 181.
4. A. T. Glenny, G. A. H. Buttle, and M. F. Stevens, “Rate of Disappearance of Diphtheria Toxoid Injected into Rabbits and Guinea-Pigs: Toxoid Precipitated with Alum,” Journal of Pathology 34 (1931): 267–275.
5. R. G. White, A. H. Coons, and J. M. Connolly, “Studies on Antibody Production. III. The Alum Granuloma,” Journal of Experimental Medicine 102 (1955): 73–82.
6. N. W. Baylor, W. Egan, and P. Richman, “Aluminum Salts in Vaccines—US Perspective,” Vaccine 20 (2002): S18–S23.
7. J. G. Dórea and R. C. Marques, “Infants’ Exposure to Aluminum from Vaccines and Breast Milk during the First 6 Months,” Journal of Exposure Science and Environmental Epidemiology 20 (2010): 598–601.
8. N. Chuchu, B. Patel, B. Sebastian, and C. Exley, “The Aluminium Content of Infant Formulas Remains Too High,” BMC Pediatrics 13 (2013): 162.
9. R. E. Litov, V. S. Sickles, G. M. Chan, M. A. Springer, and A. Cordano, “Plasma Aluminum Measurements in Term Infants Fed Human Milk or a Soy-Based Infant Formula,” Pediatrics 84 (1989): 1105–1107.
10. B. Flannery, S. B. Reynolds, L. Blanton, T. A. Santibanez, A. O’Halloran, P.-J. Lu, et al., “Influenza Vaccine Effectiveness against Pediatric Deaths, 2010–2014,” Pediatrics 139 (2017): e20164244.
11. D. G. McNeil Jr., “Over 80,000 Americans Died of Flu Last Winter, Highest Toll in Years,” New York Times, October 1, 2018, www.nytimes.com/2018/10/01/health/flu-deaths-vaccine.html.
12. K. A. Poehling, K. M. Edwards, G. A. Weinberg, P. Szilagyi, M. A. Staat, M. K. Iwane, et al. “The Underrecognized Burden of Influenza in Young Children,” New England Journal of Medicine 355 (2006): 31–40.
13. NIH, National Institute of Neurological Disorders and Stroke, “Guillain-Barré Syndrome Fact Sheet,” www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Guillain-Barre-Syndrome-Fact-Sheet.
14. P. Haber, F. DeStefano, F. J. Angulo, J. Iskander, S. V. Shadomy, E. Weintraub, et al., “Guillain-Barré Syndrome following Influenza Vaccination,” JAMA 292 (2004): 2478–2481.
15. W. K. Yih, E. Weintraub, and M. Kulldorff, “No Risk of Guillain-Barré Syndrome Found after Meningococcal Conjugate Vaccination in Two Large Cohort Studies,” Pharmacoepidemiology and Drug Safety, December 6, 2012, 1359–1360.
16. S. B. Black, H. R. Shinefield, R. A. Hiatt, and B. H. Fireman, “Efficacy of Haemophilus Influenzae Type B Capsular Polysaccharide Vaccine,” Pediatric Infectious Disease Journal 7 (1988): 149–156.
17. L. H. Harrison, C. V. Broome, A. W. Hightower, C. C. Hoppe, S. Makintubee, S. L. Sitze, et al., “A Day Care–Based Study of the Efficacy of Haemophilus B Polysaccharide Vaccine,” JAMA 260 (1988): 1413–1418.
18. M. T. Osterholm, J. H. Rambeck, K. E. White, J. L. Jacobs, L. M. Pierson, J. D. Neaton, et al., “Lack of Efficacy of Haemophilus B Polysaccharide Vaccine in Minnesota,” JAMA 260 (1988): 1423–1428.
19. E. D. Shapiro, T. V. Murphy, E. R. Wald, and C. A. Brady, “The Protective Efficacy of Haemophilus B Polysaccharide Vaccine,” JAMA 260 (1988): 1419–1422.
20. D. J. Granoff, P. G. Shackelford, B. K. Suarez, M. H. Nahm, K. L. Cates, T. V. Murphy, et al., “Hemophilus Influenzae Type B Disease in Children Vaccinated with Type B Polysaccharide Vaccine,” New England Journal of Medicine 315 (1986): 1584–1590.
21. R. S. Daum, S. K. Sood, M. T. Osterholm, J. C. Pramberg, P. D. Granoff, K. E. White, et al., “Decline in Serum Antibody to the Capsule of Haemophilus Influenzae Type B in the Immediate Postimmunization Period,” Journal of Pediatrics 114 (1989): 742–747.
22. C. D. Marchant, E. Band, J. E. Froeschle, and P. H. McVerry, “Depression of Anticapsular Antibody after Immunization with Haemophilus Influenzae Type B Polysaccharide-Diphtheria Conjugate Vaccine,” Pediatric Infectious Disease Journal 8 (1989): 508–511.
23. Institute of Medicine (US) Vaccine Safety Committee, K. R. Stratton, C. J. Howe, and R. B. Johnston Jr., Haemophilus Influenzae Type B Vaccines (Washington, DC: National Academies Press, 1994).
24. C.-Y. Fang, C.-C. Wu, C.-L. Fang, W.-Y. Chen, C.-L. Chen, “Long-Term Growth Comparison Studies of FBS and FBS Alternatives in Six Head and Neck Cell Lines,” PLoS One 12 (2017): e0178960.
25. J. Dumont, D. Euwart, B. Mei, S. Estes, and R. Kshirsagar, “Human Cell Lines for Biopharmaceutical Manufacturing: History, Status, and Future Perspectives,” Critical Reviews in Biotechnology 36 (2016): 1110–1122.
26. Mad cow disease is also known as bovine spongiform encephalopathy.
27. A. H. Peden, M. W. Head, D. L. Ritchie, J. E. Bell, and J. W. Ironside, “Preclinical vCJD after Blood Transfusion in a PRNP Codon 129 Heterozygous Patient,” Lancet 364 (2004): 527–529.
28. B. S. Appleby, M. Lu, A. Bizzi, M. D. Phillips, S. M. Berri, M. D. Harbison, et al., “Iatrogenic Creutzfeldt-Jakob Disease from Commercial Cadaveric Human Growth Hormone,” Emerging Infectious Diseases 19 (2013): 682–684.
29. About 270 pounds for those still stuck on non-SI units.
30. CDC, “Variant Creutzfeldt-Jakob Disease: vCJD Cases Reported in the US,” page last reviewed October 9, 2018, www.cdc.gov/prions/vcjd/vcjd-reported.html.
31. CDC, “Immunization Schedules: Table 1: Recommended Child and Adolescent Immunization Schedule for Ages 18 Years or Younger, United States, 2019,” page last reviewed February 5, 2019, www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html.
32. CDC, “Vaccines for Your Children: Who Sets the Immunization Schedule,” page last reviewed March 8, 2012, www.cdc.gov/vaccines/parents/vaccine-decision/sets-schedule.html.