Quotes of the Day

When an Iowa College student returned from a class trip to India last month, he brought back more than the usual souvenirs. The man, 19, was infected with measles, a disease that is largely under control in the U.S. but is endemic in India and can cause high fevers, deafness, inflammation of the brain and even death. He wound up infecting at least one other person on the plane, and Iowa health officials confirmed last week that a third person later developed the disease on the ground.

What happened? It turns out the young man, like several others in his college group, comes from a family that doesn't believe in vaccination, and so he had never had his measles shots. Altogether, six people in the group developed the illness while in India. When doctors at the Iowa Department of Public Health learned about their condition, they asked the ailing students and their unvaccinated traveling companions to delay their return to the U.S. so as not to spread the infection. Instead, says Kevin Teale, a spokesman for the public-health department, the 19year-old "came back early against our advice."

With any luck, the Iowa outbreak may be limited to just the three cases. But it raises an important question: Why would anyone choose not to get vaccinated? For some it's a matter of religion. For others it's a concern about possible side effects. All vaccines have some small risk. Some parents and even a few doctors also are worried that recent increases in the rate of autism and earlier occurrences of Type 1 diabetes could have been caused by routine childhood vaccines.

It has taken a while, but the best and largest studies have shown that not to be the case. Eighteen months ago, a giant study of practically every child in Denmark found no causative link between autism and the so-called MMR shot — the triple vaccine against measles, mumps and rubella. Another big Danish study last week found no link between various childhood vaccines and Type 1 diabetes.

The Iowa incident reminds us that when people decide — for any reason — not to vaccinate, they are endangering not just themselves but everyone around them.

• Christine Gorman