April 11, 2011— -- Although most people think of measles as a pimply plague of the past, U.S. families traveling or living abroad should take extra precautions because of increasing cases among residents returning from Europe, Africa and Asia.
U.S. infants and toddlers spending time overseas should be vaccinated earlier than those living in this country, the federal Centers for Disease Control and Prevention recommended Friday as part of a report on cases imported by tiny travelers. Young children are more vulnerable to severe measles infections and at greater risk of death or encephalitis, a dangerous brain inflammation.
Before heading overseas, U.S. children aged 6 to 11 months should receive one dose of the measles, mumps and rubella (MMR) vaccine, while those at least 1 year old should receive two doses spaced at least 28 days apart. That compares with the general recommendation to give the first dose at 12-15 months, and a second before starting kindergarten. The CDC since 1989 has advised accelerating measles vaccinations for youngsters headed to regions with known outbreaks, although it's unclear how many parents have heeded the guidance.
The latest public health warning about "imported cases" might surprise parents and some doctors, as measles largely has fallen off the U.S. radar screen since 2000, when it was declared eliminated within our borders.
More worrisome to U.S. moms and dads might be news that measles has been on the upswing in such developed countries as Great Britain, Switzerland, France and Spain. According to the CDC, 39 percent of U.S. measles imports in 2005-2008 originated in Europe.
"Despite the fact that it's been in the news in Europe, we believe that people in the United States are largely unaware that there is measles in Europe," Dr. Gregory L. Armstrong, a medical epidemiologist with the CDC in Atlanta, said in an interview Friday.
In 1994, health officials pronounced measles gone from the United Kingdom, only to declare it endemic again in 2008 because of falling immunization levels, he said. Cases have been increasing in France, Switzerland, and lately in Spain.
"By and large, these cases are occurring in people who are born in those countries and who are philosophically opposed to vaccination," Armstrong said.
CDC Reviews 13 Recent Cases Acquired Overseas
Armstrong and colleagues from the CDC and state health departments analyzed 13 cases in which U.S. residents who recently returned from traveling or living abroad developed measles during the first two months of 2011. Seven of the patients were unvaccinated children younger than 2 years from Massachusetts, Texas, New York, Pennsylvania, Washington and California.
All seven ultimately recovered, although four were hospitalized with diarrhea, dehydration, fever or pneumonia, according to the CDC Morbidity and Mortality Weekly Report released last week. In three youngsters, diagnosis was delayed because doctors didn't recognize measles as a possible source of the children's rashes.
Most of the sick children's families "were not philosophically opposed to vaccination," Armstrong said. "They were unaware they could have been vaccinated at a younger age, or they had had an opportunity to get their child vaccinated but missed that opportunity for some reason. A lot of these children were a little bit delayed in their immunizations."
The latest cases "provided an opportunity to remind people that it's important to check the vaccination status of their kids before traveling," he said.
Before measles vaccines became available, hundreds of children died each year, thousands developed encephalitis and a quarter of them suffered permanent brain damage, he said. "People have forgotten just how severe measles is," he added.
The seven pediatric cases tallied in January and February alone roughly equaled the number of pediatric cases seen each year from 2001 to 2010. During that decade, CDC received reports of 159 imported cases, 47 of them among children younger than 2.
The children in the Morbidity and Mortality Weekly Report had traveled to at least six countries in Asia, Africa and the Caribbean. An investigation into a case picked up in the Dominican Republic strongly suggested transmission from a European tourist who had roomed next door to the family at an international resort.
Investigators probing the case of an infected child who had spent time in Haiti found no evidence the viral illness originated in that poor island nation, although a second U.S. resident who developed measles at about the same time was found to have been in the same international airport terminal, within the same two-hour period, as the sick child.
Many Doctors Unfamiliar With Measles Because of Vaccine Successes
The highly contagious measles virus spreads through tiny droplets in the air, producing a telltale rash, and flu-like symptoms including high fever and a runny nose. Travelers can be exposed by breathing the same air as someone who is infected, such as in confined areas such as airports or airplanes, the CDC said. An estimated 1.9 million U.S. children travel overseas each year.
Armstrong and his co-authors wrote that U.S. doctors should "maintain a high level of suspicion for measles in patients with febrile rash illnesses and recent travel outside the United States" and advised them to report suspected cases to local health authorities and obtain specimens for testing and confirmation.
Of particular note to the authors was that in one of the 2011 cases, parents had asked their pediatrician about vaccination before traveling and were told it wasn't needed. Unfortunately, doctors may learn about measles in medical school, "but unless they work overseas, they're unlikely to see many cases of it, and it's frequently not recognized at first," Armstrong said.
Although the CDC report focused on cases among the youngest children, parents' decisions to delay or refuse vaccinations for their children have put older U.S. kids at risk when they venture abroad, said Dr. Terri Rock of Santa Monica, Calif., a family practice doctor who specializes in travel medicine.
"You can't imagine how many people we see for travel whose families don't vaccinate," Rock said.
When it comes time for their 17-year-old sons or daughters to go to developing countries for high school community service projects, they turn up in her office with lists of required immunizations for illnesses such as yellow fever and typhoid.
Rock views those appointments as opportunities to talk about "what is a reasonable precaution. I will say things like, 'I wouldn't give you your typhoid before I give you your MMR.'"
Sometimes, she gets through.
Imported Cases Can Spread to Unimmunized Adults and Children Alike
A potential obstacle is that autism frequently appears in toddlers at about the same time as they receive the MMR vaccine, leading many parents to believe it can cause the developmental disorder. This has driven a significant number of parents to refuse to vaccinate their children.
Their fears were stoked by a now-discredited 1998 report in the Lancet from Dr. Andrew Wakefield, a U.K. doctor who claimed to have established a link between vaccines and the disorder.
Measles can infect unimmunized adults and children. The same issue of the Morbidity and Mortality Weekly Report included a field report of a measles outbreak involving 13 people in Hennepin County, Minn., in February and March.
Those who became sick ranged from 4 months to 31 years. Investigators traced the cases to a U.S.-born child from a Somali family who developed a rash about two weeks after returning from Kenya. The child, who was 2½ years old, had been dropped off at a child-care center a day before the symptoms began.
Three children from the center subsequently developed measles, as did four people living in two homeless facilities, two emergency room patients and three others. Six of the measles patients, all of Somali descent, weren't vaccinated because of parental concerns about vaccine safety, the report said.
"Importations of measles from other countries still occur, and low vaccination coverage associated with parental concerns regarding the MMR vaccine puts persons and communities at risk for measles," the report authors wrote.