BOSTON — Measles, a preventable disease that has been largely vanquished in the United States, continues to show up sporadically in the population as unvaccinated people traveling to other countries unwittingly bring back infections, researchers report. Data released at a meeting of the Infectious Diseases Society of America show that 2011 has been a bad year for this kind of spread, with the highest number of U.S. measles cases since 1996.
Other data from the meeting indicate that many U.S. pediatricians are doing their best to keep these cases away from their patients, turning away families that refuse to have their children vaccinated — whether against measles or other diseases.
There have been 214 measles cases in the United States so far this year, says epidemiologist Huong McLean of the Centers for Disease Control and Prevention in Atlanta. Of these patients, 68 were hospitalized and 12 developed pneumonia. Roughly 86 percent of people who contracted measles were either unvaccinated or had unknown vaccination status, the CDC data show.
The measles influx has been highly sporadic, with 73 different people bringing in an infection, McLean says. Most were U.S. residents visiting Europe. “They’re having a big year in Europe, and we’re feeling the effects here,” she says, noting that Europe has reported 28,000 cases of measles in 2011 so far, many in France.
In Canada, Quebec province has had 759 cases, says Gaston De Serres, a physician and epidemiologist at Laval University in Quebec City. The 2011 toll in Canada as a whole is now 783, the highest since 1995.
The spotty measles outbreaks are a far cry from the pre-vaccination days in the 1960s, when the United States could expect hundreds of thousands of infections and thousands of people hospitalized. But they are notable compared to the past decade, which has typically seen no more than a few dozen measles cases annually in the United States.
When a measles outbreak is reported, standard public health measures are mobilized to limit the spread. For example, in Utah this spring, 184 people were quarantined when an unvaccinated student returned home from Europe with measles and nine people became ill, according to epidemiologist Karyn Leniek of the Utah Department of Health in Salt Lake City.
At the clinical practice level, some doctors are taking a preemptive approach. Physicians Chris Harrison and Tom Tryon of the University of Missouri in Kansas City presented data from a survey of more than 900 pediatricians in nine states showing that 21 percent stopped accepting appointments from families that refused to have their children vaccinated. In Minnesota that rate was only 1 percent, but in Iowa it was closer to 38 percent.
“This has become an increasingly controversial issue,” Harrison says. Doctors typically give such families a 30-day warning to find another practice, he says. Tryon says he simply doesn’t accept vaccine-refusing families in his practice, citing “concerns about the effect that preventable diseases might have in my waiting room.”
“There is a misperception regarding vaccines,” says Saad Omer, an epidemiologist at Emory University in Atlanta who has studied the vaccine refusal issue. Many younger parents, he says, “are coming of age in an era where they don’t see these diseases. But they hear of real or perceived adverse events from vaccinations.”
Resolving doubts about vaccination will require physicians to communicate with and counsel their patients, he says. “This issue is not going to go away on its own.”