Written by Eva Hamrud, PhD
September 19, 2019
14 min read
Topic Review: Vaccines
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TOPIC INTRO
In 1998, the medical journal The Lancet published an article titled “Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children.” Authored by British doctor Andrew Wakefield and 11 coauthors, the article purported to find evidence that the MMR vaccine — which targets measles, mumps, and rubella — caused autism and gastrointestinal disorders.
In the years following the publication, hundreds of studies demonstrated no link between vaccines and autism, and scientists harshly criticized Wakefield’s methodology and his failure to disclose conflicts of interests. In 2010, The Lancet fully retracted the original article and Wakefield was stripped of his medical license that same year.
But by then, the damage was already done. Many parents, fearful of causing their children to develop autism, refrained from vaccinating them, and we’re now treated to regular headlines of measles and mumps outbreaks among children. The journal The Annals of Pharmacotherapy characterized Wakefield’s study as “perhaps the most damaging medical hoax of the 20th Century.” Despite the paper’s retraction, vaccine misinformation continues to proliferate and social media, and the “anti-vaxxers” movement is showing no signs of slowing down.
Because of the wide dispersal of misinformation, it’s important to hear directly from the experts about the importance of vaccinations. That’s where Metafact comes in. In this week’s review, we hear from a range of scientists across the globe about vaccine side effects, supposed toxic ingredients, and the safety of herd immunity. Stay tuned…
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NUMBERS
Meta-Index
7 Kings and Queens killed by Smallpox
40% Population decline in one year (A.D. 1520) from Smallpox in the Aztec capital city, Tenochtitlan.
300,000,000 Estimated deaths from Smallpox during the 20th century
1796 Year Edward Jenner gets rejected by the Royal Society for his smallpox experiment
1798 Year Edward Jenner self-publishes “An Inquiry into the Causes and Effects of the Variolae Vaccinae, a disease discovered in some of the western counties of England, particularly Gloucestershire and Known by the Name of Cow Pox”
1980 Year when naturally occurring Smallpox eradicated on earth
450 to 1 The benefit to cost ratio of the World Health Organisation smallpox eradication program between 1967-1977
116,300,000 Number of doses administered of diptheria-tetanus-pertussis vaccine worldwide in 2018
2,500,000 Lives saved annually by immunization programs
20,400,000 Lives saved by measles vaccine between 2000-2016
1,007,332 Annual number of reported cases in USA during 19th century for Smallpox, Diphtheria, Measles, Mumps, Whooping Cough and Polio
21,122 Annual number of reported cases in the USA population in 2016 for Smallpox, Diphtheria, Measles, Mumps, Whooping Cough and Polio
97.9% Decrease in reported cases in USA between 19th century and 2016
ORIGIN STORY
Of milkmaids, kings and Edward Jenner
In 1796, London was gripped with fear. One in five of deaths came from smallpox, a contagious air-borne virus that would cripple the immune system. Smallpox dates back thousands of years. The mummy of Egyptian King Ramses V, who died in 1157BC, was found to bear the trademark rash. It kills approximately one in three of those infected. Today, smallpox is famous for being the first disease that humankind eradicated from the planet. This immense achievement came about from a serendipitous discovery in country England.
In the 18th century, something curious happened to milkmaids in the English countryside. They would never get smallpox. In 1762 a milkmaid gloated to a curious boy that “I shall never have smallpox for I have had cowpox [and] I shall never have an ugly pockmarked face”. The teenager was Edward Jenner who later became a doctor.
In 1796, Jenner tested the milkmaid idea. He infected eight-year old James Phipps with cowpox using pus gathered from the blisters of Sarah Nelmes, a milkmaid. He then exposed Phipps to smallpox and noticed he didn’t contract the virus. Once vaccinated, a patient develops antibodies that make them immune to not only cowpox but smallpox too. The Latin word for cow is vaccus while cowpox is vaccini; so Jenner coined the term ‘vaccination’ to describe the technique.
In the 1870s, French scientist Louis Pasteur developed a similar method to protect people against Rabies and Anthrax. In honor of Jenner, he called the preparation a ‘vaccine’. (Some dispute the Milkmaid story and claim John Fewster should take more of the credit).
Discovering vaccines was huge — getting vaccines to millions was the next challenge. In 1967 smallpox was still killing up to 2million people in the poorer parts of the world. The World Health Organisation invested US$100million over the next 10 years. In 1977, the last person to ever get smallpox was Ali Maow Maalin, a Somalian hospital cook. Smallpox was the first, but now vaccines protect many diseases.
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TIMELINE
Timeline for human vaccines
Smallpox (1798), Rabies (1885), Typhoid (1896), Cholera (1896), Plague (1897), Diphtheria (1923), Pertussis (1926), Tuberculosis (1927), Polio (1955), Measles (1963), Mumps (1967), Rubella (1969), Anthrax (1970), Hepatitis-B (1986), Cholera (1991), Meningococcal (1999), Human papillomavirus (2006). Source
META-TRENDS
US children immunisation rates
META-TRENDS
Reported cases of whooping cough in the US
META-TRENDS
Estimates of flu vaccine effectiveness
THE CONSENSUS
Do vaccines cause Autism?
Read the full answers to this question here. Despite the retraction of the Lancet article, there’s still widespread suspicion that vaccines actually do cause autism. So what evidence do we have that they don’t?
Our experts were unambiguous in their rulings on this topic. “There is absolutely no single shred of evidence that vaccination, of any type, causes autism,” wrote Mark Pepys, professor of medicine at University College London. “There is also absolutely no shred of scientific evidence about either vaccination or autism suggesting any possible mechanism that could be responsible for such an association.”
One claim on the internet is that the preservative thimerosal, which was once used in some vaccines, contained mercury and led to adverse effects, including autism. But studies couldn’t find any evidence of this, and thimerosal was later removed from most vaccines out of an abundance of caution. “The rates of autism have risen in the US after the thimerosal was removed, further supporting the safety of the vaccines,” noted University of Pittsburgh associate professor Richard Zimmerman. “Something else must be causing autism if children are getting it despite thimerosal’s removal.”
Indeed, scientists like Dwight German, a professor at UT Southwestern Medical Center, have engaged in animal studies to determine whether such effects exist. “We recently studied the brains and behavior of non-human primates, exposed to the same human childhood vaccination schedules to determine whether neurodevelopmental changes occur,” he wrote. “… We found that the vaccines/thimerosal caused no behavioral or brain abnormalities that are characteristic of ASD.” How could a vaccine not cause harm if it contains mercury? As Amelia Warren, an expert at Bond University, explained, “the amount of organic mercury found in a single serving of tuna (e.g., one can) is equivalent to the amount found in a single vaccination shot.”
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THE CONSENSUS
Are there toxic ingredients in vaccines?
Read the full answers to this question here. We’ve established that mercury doesn’t pose a threat. But what about the other ingredients in vaccines? Are any of them toxic?
All of our experts agreed they’re not toxic. While it’s common for vaccines to cause some inflammation and soreness, this doesn’t mean they’re toxic, and most governments closely monitor the industry to detect any potential problems early on. “There are surveillance systems in place to monitor vaccine-related adverse events,” wrote Kate Zinszer, an expert from Université de Montréal. “The risks of adverse events greatly outweigh the benefits vaccines provide at the individual and community level. To ensure the safety of vaccines, federal agencies in Canada, the US and worldwide routinely monitor and conduct research to examine any new evidence that would suggest possible problems with the safety of vaccines.”
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THE CONSENSUS
Do I need to get vaccinated if everyone else is?
100% Affirmative via 23 experts
Read the full answers to this question here. When reading about vaccines, you’ll likely come across the term “herd immunity,” which describes the phenomena by which diseases have a difficult time spreading in populations where vaccine rates are high. In this scenario, an unvaccinated individual would be unlikely to contract a disease because everybody they come into contact with is immune to it.
This has led some to wonder whether it’s worth getting vaccinated if you live in an area with vaccination rates above 90%.
All experts agreed that you should still be vaccinated. For one, if everyone adopts the position that herd immunity will protect them, then that would naturally lead to less herd immunity. “If an individual decides that he/she, or their child is protected because of the ‘firewall’ and therefore has such a low chance of getting the infection that they decide not to bother getting the vaccine, then they do not contribute to the firewall, creating a small crack in it,” wrote Michael Mina, an assistant professor of epidemiology at Harvard. “At a population level, it is likely that their decision was either informed by or will inform other people’s decisions to not vaccinate for the same reason. And very quickly, the firewall will contain many cracks because many people think that there is no need.”
What’s more, a vaccination rate is just a rough generalization and doesn’t really reflect your chances of encountering an unvaccinated individual. “The estimate is representative of a closed population where susceptible individuals are scattered evenly throughout,” wrote cancer epidemiologist Michaela Hall. “In practice, the population is not closed, many people travel to and from other countries without high MMR vaccine coverage rates and additionally, unvaccinated individuals are often concentrated within local areas or groups, meaning that herd protection may be significantly reduced in some areas.”
Also, if a disease is highly contagious, then a much higher vaccination rate is required to reach herd immunity. “In a totally susceptible population, one person infected with measles on average infects 20 other persons,” explained Cornelis H van Werkhoven, an expert at University Medical Center Utrecht. “The World Health Organisation (WHO) recommends that, in order to prevent spread of measles in the population, over 95% of the population should be vaccinated.”
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THE CONSENSUS
Is the HPV vaccine safe?
100% Affirmative via 11 experts
Read the full answers to this question here. The HPV vaccine, which vaccinates one from certain strains of the human papilloma virus, was introduced to the population in 2006, and it’s recommended by the World Health Organization because of its ability to prevent cervical cancer.
Given its relative newness, some Metafact users have wondered if it’s safe.
All the Metafact experts agreed that it was. “Over 80 million doses of the vaccine have been administered around the world and safety has been closely monitored by a number of organisations,” explained University College London cancer researcher Jo Waller. “All have concluded that the HPV vaccine is safe.” Gregory D. Zimet, a professor of pediatrics at Indiana University School of Medicine pointed to a study comparing unvaccinated females to vaccinated females that “failed to find any differences in rates of multiple sclerosis or other demyelinating diseases.”
Zimet noted that, though it’s impossible to eliminate all risks pertaining to vaccines, they’re still overwhelmingly safe. “HPV vaccination is not 100% safe, but no activity in life is 100% safe, even getting out of bed in the morning. However, we can say with 100% certainty that getting vaccinated against HPV is safer than not getting vaccinated and that vaccinating a child against HPV is safer, for example, than having a child ride in a car wearing a seatbelt.”
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QUICK ANSWERS WITH CONSENSUS
Do multiple vaccines overload the immune system? Extremely unlikely. As one of our experts put it, “a baby could theoretically respond to 10,000 vaccines at once.” Some studies suggest that multiple vaccines do not overload the immune system and infants can handle them safely, while other studies indicate potential concerns like reduced immunogenicity or links to metabolic conditions.
Is a universal flu vaccine possible? Maybe. “There is a theoretical possibility to vaccinate against targets common between strains, using novel immunological approaches.” These studies suggest that a universal flu vaccine is possible by targeting conserved viral epitopes, using novel vaccination platforms, and leveraging new technologies, although challenges remain in achieving consensus on its efficacy and protection spectrum.
Is the influenza vaccine effective? Yes. It’s not 100% effective, but it significantly reduces your chance of getting the flu. Some studies suggest the influenza vaccine is effective in reducing illness, hospitalization, and mortality, particularly in high-risk groups and children, while other studies indicate reduced or low effectiveness in elderly individuals, especially when vaccine strains do not match circulating strains.
Does the HPV vaccine increase risk of blood clots? No. Both studies reviewed provide strong evidence that the HPV4 vaccine does not increase the risk of venous thromboembolism among females aged 9-26 years. These findings should reassure healthcare providers and patients about the safety of the HPV4 vaccine in terms of blood clot risk.
TOP ANSWER
How long is the measles vaccine good for?
Ian Frazer: An expert from University of Queensland in Vaccines, Vaccinology
“Measles infection seems to give lifelong immunity – an experiment of nature showed this when measles was reintroduced into an isolated island community after a long (about 50 year) gap, and those who were on the island during the last epidemic did not get measles whereas the younger members of the community born after the last epidemic were susceptible.
For the vaccine, we’re not sure that there is lifelong immunity in all immunised individuals – which is one of the reasons why in many countries measles immunisations are given to 1 year olds and then again at age 12 because there was a suggestion of waning immunity from the vaccine over time in some people.”
Read many experts answers here on this topic.
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TAKEAWAYS
- There’s no evidence that vaccines cause autism. So don’t believe what celebrities tell you.
- Sure, vaccines come with risks from adverse reactions, but nearly everything you do has some risk involved. Bottom line: the risks posed by not getting vaccinated are far greater than the risks associated with vaccines.
- Herd immunity helps protect you, but don’t let it serve as a stand-in for getting vaccinated.
- Don’t believe anti-science celebrities and activist claims on Facebook or Youtube. Opinion is free, but facts are sacred.
- Throughout their history, vaccines have saved millions of lives. Maybe even your own. So enjoy your life!
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