More than half of U.S. travelers who should get thebefore they go abroad are not getting the shot, putting many others at risk when they return home, a new study finds.
The research, published today in the Annals of Internal Medicine, is important, experts say, because most measles outbreaks in the United States can be who become infected overseas.
"There continues to be measles importations into the U.S. which then can provokein different communities," lead author Emily Hyle, M.D., an infectious disease physician at Massachusetts General Hospital, told CBS News.
. A single case of imported measles can wind up sickening a dozen or more unvaccinated people.
"Measles is incredibly contagious. Ninety percent of non-immune individuals will become ill with measles if they're exposed," Hyle said. "And that exposure can be as minimal as walking into a room up until two hours after somebody infected with measles has been there."
Since 1989, clinical guidelines from the CDC Advisory Committee on Immunizations have called for all U.S. international travelers to be vaccinated with two doses of MMR vaccine before their trip unless a blood test shows they have measles immunity, they had a documented case of the measles, or they were born before 1957 (when the disease, and resulting immunity, were widespread in the U.S.).
For the study, Hyle and her team wanted to find out how clinicians who are experienced in providing pre-travel medical advice check for measles immunity. They also sought to determine the reasons why people traveling abroad who should get the vaccine choose not to do so.
The researchers analyzed data collected between 2009 to 2014 from 24 GlobalTravEpiNet clinics.
Of the 40,810 people included in the analysis, 16 percent were eligible to receive the MMR vaccine — meaning they were not immune and could contract and spread the virus — but more than half of them opted not to get it.
What's more, three-quarters of that group reported skipping it because they said were not concerned about the disease. In more than a quarter of cases, the medical provider deemed the vaccine unnecessary.
But many may not realize that by skipping the vaccine, they are putting others, including vulnerable young children, at risk.
"We worry about both immunocompromised patients and the very young," Hyle said. "Those are. They're not able to take the live virus vaccine and then measles illness can be much more serious in those patients."
The researchers say the findings underscore the need to improve both provider and traveler knowledge of measles as a travel-related illness and the need to increase pre-travel MMRin those who are eligible.
"If providers have conversations and point out that it's not just their own health that's at risk, which is of course very important, but also the health of the community around them, I do think people might think differently about whether or not they'd be willing to have the vaccination," Hyle said.
Experts say the best time to see your doctor orto discuss your health needs, including vaccines, is four to six weeks before your trip.
In an accompanying commentary in the Annals of Internal Medicine, Lori Handy, M.D., of Thomas Jefferson University, and Paul Offit, M.D., of the University of Pennsylvania, urge all unvaccinated travelers who are medically able to receive MMR vaccine to do so.
"The risks are minimal for the individual who receives the vaccine and are greatly outweighed by the benefit to the traveler, as well as to society, on his or her return," they write. "If persons traveling abroad continue to underestimate the importance of pretravel MMR vaccination, our society is destined to be affected by imported cases of measles, leading to morbidity and mortality from this disease."