Scientists and public health officials have celebrated vaccines as one of the greatest medical breakthroughs of human history. But despite the widespread scientific consensus that vaccines are safe and effective, there's still a lot of misinformation about them and their effects.
Myth #1: Vaccines cause autism
The scientific evidence on this issue is very clear: vaccines are safe, and they don't cause autism.
But in 1998, an esteemed medical journal published a paper with a startling conclusion: the measles, mumps, and rubella (MMR) vaccine — administered to millions of children across the globe each year — could cause autism.
This study, led by now-discredited researcher Andrew Wakefield, is where the modern vaccine-autism controversy started. It has since been thoroughly debunked: The Lancet retracted the paper, investigators described the research as an "elaborate fraud," and Wakefield lost his medical license.
Still, the damage was done. Wakefield's since-debunked study helped foster an anti-vaccine movement that still sees itself, despite all the evidence, as uncovering the real science on vaccines.
The Wakefield study was bad science. It involved only 12 study subjects and later investigations found that researchers had manipulated all of their medical records. Even worse, when the General Medical Council, the UK's medical regulator, began to investigate Wakefield, they found he had paid children at his son's 10th birthday party to donate blood for his research. That's far removed from a controlled and ethical setting.
Study after study since the Wakefield report found no connection between autism and vaccines. In a broad 2011 analysis of vaccines and their adverse effects, the Institute of Medicine (IOM) concluded vaccines are not linked with autism or other serious medical problems, including type 1 diabetes. The study looked at vaccines for various diseases, including MMR, HPV, and hepatitis A, and found no serious side effects to be prevalent among people with healthy immune systems.
Another meta-analysis published in 2009 in the Oxford Journals concluded vaccines with thimerosal, a mercury-containing compound found in some vaccines, don't cause autism. And research published in 2010 in Pediatrics found timely vaccination produced no adverse effects on neuropsychological outcomes seven to 10 years after the vaccines were administered.
Still, like all forms of medicine, there are some rare and typically minor side-effects to vaccines. Some of the minor side effects documented by the Centers for Disease Control and Prevention and Institute of Medicine are fever, allergic reactions, and fainting. Vaccines can also cause serious side effects in very rare situations; the smallpox vaccine, for example, has a one- or two-in-million chance of causing death, particularly in people with weakened immune systems, according to the College of Physicians of Philadelphia.
Myth #2: Liberals are more skeptical of vaccines
Support for vaccines is fairly bipartisan, a survey from the Pew Research Center found.
After the 2014-2015 Disneyland measles outbreak, political leaders from both sides came out strongly for vaccines — from President Barack Obama and Hillary Clinton to House Speaker John Boehner and Senate Majority Leader Mitch McConnell. It's actually two Republicans — not the stereotypical, liberal anti-vaxxers — who initially suggested childhood vaccination shouldn't always be mandatory: Sen. Rand Paul of Kentucky and New Jersey Gov. Chris Christie.
So while the most public faces of the anti-vaccine movement may fit a certain political mold, the general public and political establishment is much more unanimous — and bipartisan — in its views on vaccines. The concern is when this small minority of anti-vaxxers clusters in some communities and perpetuates disease outbreaks that infect people who can't get vaccinated, such as newborns and people with compromised immune systems.
Myth #3: Vaccine skeptics are fundamentally anti-science
It can be easy to stereotype the vaccine debate as people who believe in scientific evidence versus people who don't. But that's an oversimplification. Vaccine skeptics do think they believe in scientific evidence. They can cite dozens of studies and cases. They see themselves as the side in this debate that's actually following the evidence, while the pro-vaccine side is blindly trusting in authority and ultimately getting taken in by a massive pharmaceutical scam.
In a February 2015 interview with vaccine skeptic Dan Olmsted, editor of Age of Autism, he didn't say all the research is wrong. Instead, Olmsted cited faulty interpretations of various studies as evidence vaccines can cause autism. Olmsted earnestly believes he's on the right side of the issue — and that the current research is just part of a broader cover-up.
Asked to name specific evidence of a link between vaccines and autism, Olmsted responded, "I don't know if you're familiar with William Thompson, who recently acknowledged that in fact researchers have found a link between autism and the MMR vaccine — and then it was suppressed by his colleagues at the Centers for Disease Control and Prevention. That's a pretty big bombshell that's gotten very little attention."
The problem is when you dig into the studies vaccine skeptics cite, the evidence they're relying on doesn't hold up — it's misinterpreted, selectively reported, or refracted through conspiracy theories. For example, the study Olmsted cited actually found no association between vaccines and autism, but vaccine skeptics like Olmsted have, as the blog Respectful Insolence explained, cherry-picked the results of a tiny subgroup (black males) in the research to make it seem like a connection was found — even though there's no reason to believe black boys would be more susceptible to vaccine injuries.
But knock down one bad interpretation of a study and there's always another, and another, and another. Behind the skepticism is a mistrust of the data: anti-vaxxers frequently believe that studies are manipulated or suppressed by the pharmaceutical industry, which wants to keep making money off of vaccines.
And then there's the flood of wrenching anecdotes which can't be checked, but which are reported by people who are in pain and arouse our deepest sympathies. The result is that to someone primarily consuming anti-vaccine arguments, the evidence looks overwhelming, the media's dismissal of it looks corrupt, and the victims seem very real — regardless of the scientific consensus that vaccines are safe and effective.
Myth #4: Vaccine skepticism is only about autism
Some people don't necessarily oppose vaccines, but they don't want to follow the federal government's vaccination schedule. These vaccine delayers can present just as much of a public health risk as outright deniers, because the Centers for Disease Control and Prevention's schedule is based on when people are most likely to be exposed to disease.
The delayers believe that following the federal schedule for childhood vaccinations would "overload" a child's weak immune system. This idea hinges on the belief, pushed by Bob Sears' The Vaccine Book, that children's immune systems are underdeveloped and can't take the stress of vaccines, which force the body's defenses into action to fight a weakened version of an illness.
Children's immune systems aren't actually weak. Researchers writing in the Oxford Journal of Clinical Infectious Diseases explained, "Although the infant immune system is relatively naive, it is immediately capable of generating a vast array of protective responses; even conservative estimates predict the capacity to respond to thousands of vaccines simultaneously."
The research bears this out. A study published in Pediatrics found timely vaccination resulted in no adverse effects on neuropsychological outcomes seven to 10 years after the vaccines were administered.
This makes sense, based on what we know about babies' immune systems. Once babies come out of the relative sterile environment of the womb, they're assaulted by all sorts of bacteria and viruses, forcing their immune systems to kick in to protect them.
Weakened diseases in pathogens are drops in the ocean compared to the live ones kids encounter every day, Paul Offit, an infectious diseases doctor in Philadelphia, told Vox's Julia Belluz. "The idea you're living in a more sterile world because you refuse to get these three very weakened vaccines is absurd," he said.
Other vaccine delayers or deniers simply see inoculation as unnecessary, because some vaccines protect from diseases that are no longer common in the US. But this is circular reasoning: without vaccines, those diseases would be common in the US. By not vaccinating, parents risk letting these diseases come back — as has occurred with measles.
Beyond the modern vaccine doubters, anti-vaccine movements actually date way back to the late 18th century, with the advent of the smallpox vaccine — and way before anyone had even heard of autism. Some Christian clergy said the vaccine violated religious principles because it used parts from an animal. Others voiced a lingering distrust for medicine. Still others objected to government-mandated vaccination as a violation of personal liberties.
British satirist James Gillray in 1802 captured the sentiment in a cartoon that implied people could become part-cow if they took the smallpox vaccine — since the vaccine was based on cowpox.
The smallpox vaccine never led to such outcomes. Instead, the World Health Organization in 1979 said smallpox had been eradicated worldwide, largely because of widespread inoculation.
But these kinds of victories over deadly diseases are only possible if almost everyone gets vaccinated at the right time. By refusing to vaccinate in a timely manner or at all, a minority of people make it much more difficult to wipe out diseases like measles and mumps.
Myth #5: The MMR vaccine is more dangerous because it contains three live viruses
Anti-vaccine concerns are particularly prevalent with the measles, mumps, and rubella (MMR) vaccine, because it contains three live and weakened viruses. As one parent put it to Vox's Julia Belluz, "Their immune system won't encounter those naturally."
This concern has led some parents to avoid the MMR vaccine, making it more likely that dangerous, contagious diseases like measles will spread.
But there's no evidence the MMR vaccine poses an extra risk. A 2011 review of the research by the Institute of Medicine found no serious side-effects caused by the MMR vaccine for people with healthy immune systems.
Tom Shimabukuro, deputy director of the Center for Disease Control and Prevention's immunization safety office, said the MMR vaccine doesn't cause any more adverse effects than other vaccines. According to CDC data, fevers after the MMR vaccine occur in one out of six people, and mild rashes in one in 20. More severe problems are virtually nonexistent: serious allergic reactions happen in less than one in a million cases. Deafness, long-term seizures, and permanent brain damage are "so rare that it is hard to tell whether they are caused by the vaccine."
While it might seem sensible to worry about a vaccine that includes several (weakened) viruses, the reality is these incapacitated pathogens are much weaker than what babies face on a regular basis — and denying vaccination against these diseases only makes it more likely that children will have to deal with the full versions of these viruses, which are truly dangerous and deadly.
Myth #6: Getting vaccinated is only about protecting yourself
Part of the point of vaccination is keeping yourself safe from infectious diseases, but that's arguably the less important motivation. Vaccines are mostly about keeping disease from spreading to those around you, especially people who don't have strong enough immune systems to get vaccinated themselves.
There is a concept in science called "herd immunity." Vaccinated people essentially act as barriers to outbreaks, since diseases can't pass through them and infect others. If a sufficient percentage of the herd is immune, diseases can't spread to enough people to thrive.
This barrier helps protect some of the most vulnerable populations: infants under 12 months of age, who can't get vaccinated and are more susceptible to infection; the elderly, who have a higher risk of death if they contract vaccine-treatable illnesses; and people with compromised immune systems, who can't get vaccines and are more likely to die from the diseases vaccines protect people against.
The threshold for herd immunity depends on the disease and how it's transmitted. In an analysis of several vaccine-treatable illnesses, the Centers for Disease Control and Prevention set the lowest threshold of vaccine coverage at 75 percent — for mumps — and the highest at 94 percent — for measles. Even the low-end threshold requires at least three in four people to get vaccinated.
In other words, vaccines only work when almost everyone gets vaccinated, because even a small number of unvaccinated people can make it much easier for a disease to spread. Vaccination, much more than an individual goal, is a communal one. And the people most at risk when members of the herd don't get vaccinated are often people who can't reduce their risk by getting vaccinated themselves.
Myth #7: Scientists aren't sure that vaccines are safe
Scientists widely believe the science on vaccines is settled — and they want everyone to reap the public health benefits of these medicines.
The American Academy of Pediatrics, Centers for Disease Control and Prevention, National Institutes of Health, National Academy of Sciences, and World Health Organization encourage vaccination and deem it safe.
The scientific evidence, including a 2011 review of the research by the Institute of Medicine, shows vaccines are generally safe, barring a few rare, typically minor complications. And we know that these very small side effects are nothing compared to the diseases vaccines protect us against: smallpox, polio, and measles ravaged entire communities and killed millions before the invention of vaccines.
Vaccines also played a key role in eradicating and diminishing diseases like polio, smallpox, tetanus, measles, mumps, and whooping cough. And the CDC estimates that vaccines prevented 21 million hospitalizations and 732,000 deaths among US children born between 1994 and 2014, saving nearly $295 billion in direct costs and $1.38 trillion in total societal costs.
By saving the lives of millions in the time they've been around, vaccines are one of the greatest achievements in centuries of public health developments.
It's little surprise, then, that scientists and public health experts strongly support vaccines. A 2014 survey from the Pew Research Center found 86 percent of scientists with the American Association for the Advancement of Science think childhood vaccines should be mandatory, compared to 68 percent of all US adults.
Myth #8: Adults don't need to get vaccines
In most cases, it's just as important for adults to get vaccinated as children or the elderly. Not only should adults get their annual flu shot, but they should also get necessary boosters and some of the vaccines they missed as kids — both for their own protection and the health of the rest of the community.
The Centers for Disease Control and Prevention sets the US vaccination schedule. Some of the vaccines, like Hepatitis B, are administered once. Others, like the flu vaccine, are needed each year.
If you're not sure about whether you're immunized, you can ask your doctor for a blood test that will give an answer within a couple of days. For more detailed information, check out the CDC's website and talk to your doctor.
But the bottom line is very simple: get vaccinated if you're not already.
Myth #9: The US is terrible about getting vaccinated
The US actually has some of the better rates of vaccine take-up in the world, especially compared to developing countries in Africa and southern Asia.
This map from the BBC shows vaccination rates for measles across the world in 2012:
As the map shows, many countries fell below the recommended coverage rate to prevent measles from spreading. (The Centers for Disease Control and Prevention puts the required coverage rate at 83 to 94 percent for measles.) Even some European countries, including France, fell below the high-end threshold. India was also notable because its low coverage rate spans a massive population of 1.2 billion, which made huge epidemics more likely.
This doesn't mean every place in the US meets the CDC standard. There's a lot of variation from state to state — and some smaller local communities in particular can have terrible vaccination rates, exposing them to outbreaks.
But, as a whole, the US does pretty well. The unfortunate truth is that dozens of other countries don't, leaving billions of people exposed to unnecessary disease.