About a decade ago, health officials declared an "end" to measles in the United States. Now, that has changed: 131 cases of measles have been reported so far this year, more than three times the number in 2007.
Viral disease expert Dr. Jane Seward says the dramatic increase is a reminder that Americans are still at risk for measles, an easily transmissible airborne virus.
"Measles, although it's not transmitting in this country, it's just a plane ride away," says Seward, deputy director for the division of viral diseases at the National Center for Immunization and Respiratory Diseases with the Centers for Disease Control and Prevention.
"There are 20 million cases in the world, and any time people travel who are not protected through vaccination, they can bring it back if they go to a country where measles is occurring," Seward says.
Or, someone who's already infected can come to this country and spread the disease.
Either way, Seward says, the virus is increasingly finding its way to vulnerable unvaccinated populations — "mainly children whose parents have chosen not to vaccinate."
"A high proportion of those children are home-schooled. In Illinois, pretty much all of the new cases of measles were among home-schooled children — and none of them were vaccinated," she says.
Parents cite reasons like philosophical objections — which typically boil down to fears of side effects, including the development of autism.
But Dr. William Schaffner, who chairs the department of preventive medicine at the Vanderbilt University School of Medicine, says there's absolutely no scientific evidence to back that up.
"The measles, German measles and mumps vaccine — or MMR, as we call it — has been given in literally billions of doses worldwide with extraordinary safety," Schaffner says.
At the same time, Schaffner says many of those parents who opt not to vaccinate should remember that measles is a devastating disease.
"Before the measles vaccine in this country, there were 400 deaths of U.S. children each year caused by measles," he says. "Measles carries serious complications, including pneumonia and encephalitis, which is a life-threatening inflammation of the brain tissue that can be caused by viral infections such as measles. Measles is a serious illness. To be cavalier and not vaccinate shocks someone like me, who has seen the devastating effects of this disease."
If children are not vaccinated and they contract measles, they are not the only ones at risk, Schaffner says. They can put other vulnerable children at risk, too.
That group includes children with cancer who are immunocompromised and cannot tolerate the vaccine while on chemotherapy. It also includes children under the age of 1, whose immune systems are not developed enough to benefit from the vaccine.
So far this year, 15 patients have been hospitalized as a result of measles. They suffered symptoms such as high fever, dehydration and pneumonia. Four of those who were hospitalized for measles were infants.