Vaccine opt-outs put public health at risk: Our view

Measles, which once killed 450 children each year and disabled even more, was virtually eliminated in the United States 14 years ago by nearly universal use of the MMR vaccine.

But the disease is making a comeback, fueled by a growing anti-vaccine movement and misinformation that is spreading like a contagious disease. Already this year, 115 measles cases have been reported in the USA, compared with 189 for all last year.

The numbers might sound small, but they are the leading edge of a dangerous trend. When vaccination rates are very high, as they still are in the nation as a whole, everyone is protected. Diseases such as polio, smallpox and measles are wiped out. This "herd immunity" protects the most vulnerable, including those who can't be vaccinated for medical reasons, infants too young to get vaccinated and people on whom the vaccine doesn't work.

But herd immunity works only when nearly the whole herd joins in. When some refuse vaccinations and seek a free ride, immunity breaks down and everyone is more vulnerable.

That's exactly what's happening in small clusters around the country from Orange County, Calif., where 22 measles cases were reported this month, to Brooklyn, N.Y., where a 17-year-old — intentionally not vaccinated — sparked an outbreak last year in an orthodox Jewish community where many families reject vaccines.

A 2008 measles outbreak in San Diego showed how many can be put at risk by the selfish decisions of a few. The outbreak started with one intentionally unvaccinated 7-year-old and spread to 11 other children, also not vaccinated. In less than a week, the infected youngsters exposed more than 800 other people to the disease at school, at a clinic, a swimming class, a grocery store and on a flight to Hawaii.

The anti-vaccine movement was sparked by a 1998 study in a British medical journal linking the MMR vaccine to autism. That study has been thoroughly debunked. But its hold on worried parents has only grown. Fears extend to other vaccines, as well.

Whooping cough numbers have been on the rise thanks in part to resistance that has persisted for decades. In that case, the opposition is driven by a real but very small risk. Those who refuse to take that risk selfishly inflict it on others.

Making matters worse are state laws that make it too easy to opt out of what are supposed to be mandatory vaccines for all children entering kindergarten.

Seventeen states allow parents to get a "philosophical exemption," sometimes just by signing a paper saying they personally object to a vaccine. Others define religious exemptions too broadly. In Oregon, they can include almost any belief or practice.

Several states are moving to tighten laws by adding new barriers to opting out. Last year, Oregon added a small hurdle. A similar measure was moving through Colorado's Senate last week. But neither does enough to limit exemptions.

Parents ought to be able to opt out for strictly defined medical or religious reasons. But personal opinions? Not good enough. Everyone enjoys the life-saving benefits vaccines provide, but they'll exist only as long as everyone shares in the risks.

USA TODAY's editorial opinions are decided by its Editorial Board, separate from the news staff. Most editorials are coupled with an opposing view — a unique USA TODAY feature.