A complication of measles that kills children years after they have the infection is more common than thought, according to a study being presented at IDWeek 2016™. In rare cases, however, the virus can spread to the brain but go dormant.
Measles can have a fatal complication: a condition called subacute sclerosing panencephalitis.
Previously, researchers thought the risk of post-measles SSPE was one in 100,000, according to the study. "People get measles, they get better and then many years later - on average, 10 years later - it starts", said study co-author Dr. James Cherry. But the new findings, by researchers at the David Geffen School of Medicine at the University of California in Los Angeles and the California public health agency, found that for babies who get measles before being vaccinated, the rate is 1 in 609. "It's important that all kids get vaccinated so it isn't spread to younger children", he added.
There is no cure for SSPE and the only way to prevent it is to vaccinate everyone against measles, Cherry said. People with SSPE die, on average, within one or two years of being diagnosed with the disease.
The team reviewed cases in California from 1998 to 2016 to understand risk factors. All of these patients had not been vaccinated with the measles, mumps and rubella (MMR) vaccine.
They also cautioned parents about traveling with unprotected children to countries where measles is endemic. SSPE was diagnosed at a median age of 12 years, with a median latency period of 9.5 years.
Researchers do not know yet as to what causes the dormant bacteria to reactivate and there is now no cure once it does.
GETTYThe complication can cause brain damage in children
But vaccinating a very high percentage of the population results in a herd immunity, so even those who can't be vaccinated are protected because the disease is less likely to spread, Cherry explained.
Measles still circulates in Europe and Southeast Asia, so some cases will be imported to the United States every year. "That's why we need to keep up this herd immunity", Cherry said. The MMR vaccine isn't recommended until infants are 12 months old because they retain some of their mother's antibodies until that age, making the vaccine less effective, but leaving them vulnerable to measles. Others who can't get vaccinated include people with immune system disorders. Twelve (71%) of cases involved a febrile rash illness compatible with measles; all 12 had illness prior to 15 months of age and prior to measles vaccination.
"Once vaccination coverage rates start going below 90 to 95 percent, because it's so highly infectious, that's when you start to see measles". Measles is so contagious that 95 percent of people need to be vaccinated with two doses to protect those who aren't, experts say. That means all who are eligible, including adults who haven't been previously vaccinated, should receive two doses of the vaccine.
Almost 92 percent of U.S. children aged 19 months to 35 months have received the MMR vaccine, according to the U.S. Centers for Disease Control and Prevention.
Dr. Marc Siegel, a professor of medicine at NYU Langone Medical Center in New York City, added that "the measles virus is much more unsafe than the vaccine we use to protect against it". "Given how highly contagious measles is, and given how common side effects are, this is a mandate to get vaccinated and stop fooling around with fears of things like autism from the vaccine".
In 2014, the United States experienced a record 667 cases of measles, the largest number since the disease's elimination here, according to the Centers for Disease Control and Prevention.