Anti-vax myths have been around for centuries—at least since British doctor Edward Jenner developed the smallpox vaccine in the 1790s. And they persist even into our so-called scientific era: Following a 30 percent rise in worldwide measles outbreaks, in 2019 the World Health Organization (WHO) named the anti-vaccine movement among the worst health threats facing humanity.
To help cut through the noise, we examine the origins of nine of the most prominent anti-vaccine claims and uncover whether there’s scientific evidence supporting them.
1. Vaccinations cause autism.
In 2004, the SundayTimes reported on financial conflicts of interest by Wakefield, who was allegedly planning to launch a company that would profit from the boom in medical tests and lawsuits that would follow his report. After it appeared his research was fraudulent Wakefield’s co-authors withdrew their support and his story was retracted by The Lancet. “The statements in the paper were utterly false,” editor Richard Horton told The Guardian, “I feel I was deceived.”
In 2009, a British administrative court ruled that “there is now no respectable body of opinion which supports the hypothesis, that MMR vaccine and autism and enterocolitis [a devastating intestinal disease affecting premature infants] are causally linked.” Wakefield’s medical license was revoked a year later.
2. Vaccines don’t really work
Because vaccinated people greatly outnumber unvaccinated people in the U.S., the small minority of vaccinated Americans who contract a disease during an outbreak can outnumber the total number of unvaccinated people: Imagine 1,000 fully vaccinated people and five unvaccinated people are all exposed to measles. Even if just one percent of the vaccinated people fall ill, that’s still more than all the unvaccinated people combined. And even if all the unvaccinated people caught the measles, the majority of victims were vaccinated. That statistic, used in isolation, has been used to “prove” that vaccines are useless. Of course, it doesn’t take into account the 988 vaccinated people who were exposed to, but didn’t catch, the measles.
3. Vaccines contain toxins.
The level of mercury or aluminum used in any vaccine is too low to pose any danger beyond a mild allergic reaction like redness at the injection site. In 2012, the WHO’s Global Advisory Committee on Vaccine Safety (GACVS) found that mercury levels in babies’ blood returned to baseline levels a month after vaccination. Even with culmative vaccines, the GACVS determined, mercury amounts never reached toxic levels. It found that studies linking thiomersal to neurodevelopmental disorders were “fraught with methodological flaws.” Two years later, anAustralian study of more than a million children also found no link between thiomersal in vaccines and autism.
4. Vaccines can overwhelm a baby’s immune system.
Only a tiny fraction of a baby’s immune system is activated by vaccines. “Children are exposed to more antigens from a common cold than they are from vaccines,” says WHO’s Flavia Bustreo. “Giving several vaccines at the same time has no negative effect on a child’s immune system. It reduces discomfort for the child, and saves time and money.”
In addition, children are given vaccinations at a young age because that’s when they are most vulnerable to disease. Postponing or refusing vaccinations can have disastrous consequences.