Vaccines have done more than any other medical innovation to save lives and improve health. Yet the persistent and incorrect belief by a minority of parents that vaccines are more dangerous than beneficial is undermining those advances in the U.S. and parts of Europe. American public health officials worry that the trend will worsen under U.S. President Donald Trump, who has endorsed discredited connections between vaccines and autism.
Preventable diseases are making a comeback in the U.S. and Europe. A vaccine eliminated measles from the U.S. in 2000, but there were 70 cases of the potentially deadly disease in 2016, after a spike of 667 cases two years earlier. The situation is worse in Europe, where about 4,000 people were stricken in 2016. Whooping cough, a lethal hazard to babies, has remained at elevated levels since 2012, when it killed 20 people in the U.S. and 10 in the U.K. Disease outbreaks have been traced to individuals who weren’t vaccinated or were under-vaccinated and contracted the infection abroad. The number of unprotected children has grown amid a campaign to convince parents that vaccines have dangerous and common side effects, including autism, a developmental disorder associated with difficulties in speech or social interactions. Because unvaccinated children often live in geographic clusters, their communities can lose herd immunity, which occurs when so many people are protected a pathogen can’t take hold and dies out. Without herd immunity, those who can’t be vaccinated, for medical reasons or because they are too young, become vulnerable. In 2015, a Washington state woman with a compromised immune system died from measles after she was likely exposed during an outbreak in Clallam County, where resistance to immunizations was high. Even those who are immunized are at risk, as no vaccine is perfectly effective. As many as 18 percent of the measles cases in a California outbreak that began at Disneyland in late 2014 were in vaccinated people. Fears that infants’ immune systems may be overwhelmed by multiple immunizations given at once has led some parents to space them out, though studies show they are safe when given simultaneously. The result is delayed protection and in some cases vulnerability when doses are missed entirely. Trump has embraced both the ideas that vaccines cause autism and that they should be spaced out.
The anti-vaccine movement took off after the medical journal The Lancet published what turned out to be a fraudulent study in 1998 linking the measles, mumps and rubella vaccine to autism. The Lancet retracted the study in 2010 and the U.K.’s General Medical Council stripped its author, Andrew Wakefield, of his medical license for “dishonest” and “irresponsible” work. By then many parents had latched on to the ideas that vaccines were to blame for a rise in autism diagnoses. Researchers have concluded that much if not all of the increase in autism prevalence is a result of greater awareness of the disorder and changes in how it’s diagnosed. While a true increase hasn’t been ruled out, repeated studies have debunked any connection to vaccines. The myth of a link expanded in 2005 with claims that the vaccine preservative thimerosal causes autism. U.S. authorities in 1999 urged vaccine makers to reduce or eliminate thimerosal as a precautionary measure, and today every vaccine recommended for young children is available without it. Only a few others contain trace amounts, and numerous studies have shown that thimerosal-containing vaccines are safe.
In the U.S., vaccine requirements for school attendance are regulated by the states, a number of which offer exemptions to parents who cite religious or personal beliefs as a reason not to vaccinate a child. Some public health specialists support eliminating such waivers. In striking down a religious exemption, Mississippi’s Supreme Court said the state had an “overriding and compelling public interest” in protecting children. Other health advocates argue that making vaccination compulsory would harden the position of refusers. There are historical precedents. In Europe, the strongest anti-vaccination movements tend to be in countries that made vaccines mandatory in past centuries. A number of U.S. states have made vaccine exemptions harder to get. These changes have increased vaccination rates somewhat, probably by motivating parents who’d chosen exemptions out of convenience. Changing the attitudes of true vaccine refusers is much more difficult, research suggests. Australia stopped offering child-care benefits to such parents in 2016. Prominent U.S. medical ethicist Arthur Caplan suggests that the parents of unvaccinated children who sicken others, in some cases fatally, should be held legally liable.
The Reference Shelf
- The Council on Foreign Relations tracks outbreaks of vaccine-preventable diseases on this map.
- Comedy duo Penn and Teller demonstrate the value of vaccines in this video. And comedian John Oliver called out the anti-vaccine movement in his HBO television show, Last Week Tonight.
- The U.S. Institute of Medicine’s 2012 report provides evidence for actual vaccine side effects.
- This World Health Organization paper documents benefits of vaccination. This one gives the history of immunization.
- The National Conference of State Legislatures maps vaccination exemptions across the U.S.
- An outbreak of measles in Somali children in Minnesota in 2017 stemmed from fears of vaccination.
- This Bloomberg QuickTake Q&A explains why yellow fever is making a comeback.
First published Jan. 26, 2015
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Lisa Beyer at firstname.lastname@example.org