Study: State policies affect rise in unvaccinated youths

Some states make it easier for parents to opt out of program.

Despite efforts to educate the public on the risks of forgoing immunization, parents are increasingly choosing not to have their children vaccinated, especially in states that make it easy to opt out, according to a study published today in The New England Journal of Medicine.

And while the rate of children whose parents claimed exemptions remains low — slightly over 2 percent of all kindergarten students in 2011, up from just over 1 percent in 2006 — the national increase is “concerning,” said Saad Omer, an assistant professor of global health at Emory University who led the study.

Families of unvaccinated children tend to live in close proximity, increasing the risk of a hole in the immunity for an entire area. That can speed the spread of diseases such as measles, which have come back in recent years

The opt-out rate increased fastest in states like Oregon and Arizona, where it was easy to get an exemption. In such states, the rate rose by an average of 13 percent a year from 2006 to 2011, according to the study.

In states that made it harder to get an exemption from vaccination, such as Iowa and Alabama, the opt-out rate also rose, but more slowly, by an average of 8 percent a year. Washington state, once among the states with the fastest-rising opt-out rate, passed a law last year toughening requirements and saw opt-outs fall by 25 percent.

Vaccines are among the most important achievements of modern medicine. Since the first major types came into broad use in the 1940s, they have drastically reduced deaths from infectious diseases like polio and measles. But the virtual disappearance of these diseases has lulled parents into considering the vaccines against them as less necessary, public health experts say.

A distrust of the medical establishment has also fueled skepticism about vaccines. And while the Internet is a powerful source of information, it has also allowed the rapid spread of false information, such as the theory by Andrew Wakefield, a former British surgeon, that the measles-mumps-rubella vaccine was linked to the onset of autism.