(RxWiki News) Measles has typically remained rare in the U.S., unlike the years before the vaccines when children died each year from it. But 2011 was different: measles cases quadrupled in the U.S.
Typically there are about 50 to 60 cases of measles each year in the U.S., according to the Centers for Disease Prevention and Control.
But there were 222 cases of measles reported to the CDC in 2011, and half of these (112 cases) were associated with one of the 17 outbreaks reported to the agency. An outbreak means three or more cases in the same place at the same time.
"Ensure your family is vaccinated against measles."
The cases were distributed fairly evenly across age groups, with the most cases occurring in those over age 20 (76 cases). Twenty-seven children infected were under a year old.
About 90 percent of the cases - a total of 200 - were associated with measles being imported into the U.S. from outside its borders. Almost half of these came from Europe, where over 30,000 measles cases occurred in 2011, including eight deaths.
The largest groups of the imported cases were the 26 percent of U.S. residents who returned from overseas infected with measles and the 34 percent of residents who were infected from those who brought measles back with them. Only 10 percent, or 20 cases, were foreign visitors who had measles.
The majority of the cases - 86 percent - occurred in people who were not vaccinated or whose vaccination status was unknown.
"The increase in measles importations and outbreaks during 2011 serves as a reminder that measles remains endemic in many parts of the world and unvaccinated U.S. residents continue to place themselves and others in their communities at risk for measles and its complications," wrote Huong McLean, PhD, in CDC report's accompanying editorial note.
In an unvaccinated group of people who are exposed to measles, 9 out of 10 of them will catch the disease.
While measles is known for the rash it causes all over a person's body, along with a fever, runny nose and cough, it can also cause more serious problems, including inflammation of the brain leading to severe, permanent brain damage and death.
Ear infections will occur to 1 in 10 people infected with measles, and another 1 in 20 will get pneumonia. Death from measles occurs to 1 or 2 children out of every 1,000 who get it.
In fact, the disease still causes approximately 164,000 deaths every year across the world.
The best prevention for measles is the use of the vaccine, provided as part of the measles-mumps-rubella, or MMR vaccine. The first shot is given when a child is a year old and is followed with a booster between the ages of 4 and 6.
"Maintenance of high MMR vaccination coverage is essential to prevent measles outbreaks and sustain measles elimination in the United States," McClean wrote. "A drop in MMR vaccination coverage in a community can increase the risk for large, sustained measles outbreaks."
The measles vaccine is about 90 percent effective, which means that 10 percent of people who are vaccinated and then exposed to measles will still get it.
The most common side effects of the MMR vaccine include a fever in 1 of every 6 children who receive it and a mild rash in 1 of 20 kids. The vaccine can also cause a seizure from fever in 1 of 3,000 children and a temporary low blood platelet count in 1 of 30,000 children.
The most serious possible side effects include a serious allergic reaction, which occurs in fewer than 1 person for every 1 million who receive the vaccine. The other three types of serious side effects - deafness, coma or permanent brain damage - have occurred so rarely that they have not been determined to be caused by the vaccine or ruled out.
The report appeared in the April 20 issue of the CDC's Morbidity and Mortality Weekly Report.
