“I think it’s a shame. We’ve gone so many years now -- almost 19 -- without ongoing transmission,” said Walter Orenstein, MD, associate director of the Emory Vaccine Center in Atlanta. “It moves the world backwards.” Orenstein was on the panel of experts that ruled the U.S. had achieved measles elimination in 2000.
He was speaking at a panel convened by Emory University’s Global Health Institute in Atlanta to educate students and faculty about the resurgence of the virus. At the beginning of the panel, about 75% of people in the audience said they’d never seen a patient with measles.
That’s likely to change if current trends continue.
There have been 1,241 cases of measles in the U.S. in 31 states so far this year. That’s the highest number reported here since 1992, according to the CDC.
Most of those infections stem from outbreaks in New York that began in September 2018. According to Orenstein, if people continue to fall ill for longer than 12 months, and if those cases are caused by the same genetic strain of the virus, public health authorities could yank the U.S.’s measles elimination status.
Countries are declared to have eliminated measles when new cases spring up only from international travelers. If the U.S. loses its elimination status, that means infections have become endemic and the virus has taken up root here again. It would also mean that as a nation, not enough people are being vaccinated to stop the chain of transmission from person to person.
Measles is one of the most contagious diseases known to doctors. It spreads through the air. Particles of virus can float for up to 2 hours after an infected person passes through a room. People are contagious for 4 days before they show any symptoms and for as long as 4 days after they get sick.
Because it’s so easy to catch, about 95% of a population has to be vaccinated against the measles to stop it from spreading. In 2017, the latest year for which data is available, only 91.5% of toddlers in the U.S. were vaccinated, according to the CDC.
The good news is that the measles vaccine is extremely effective. Just one dose is 93% effective at preventing the disease. Two doses are 97% effective at preventing infections. Children are scheduled to get their first dose at 12 months of age. Doctors recommend a second dose between 4 and 6 years of age.
One rare but troubling complication of the measles can happen 6 to 8 years after infection. Even after a person -- typically a child -- recovers from their initial symptoms, the virus can hide in the body and resurface with devastating effects on the brain called subacute sclerosing panencephalitis, or SSPE. The disease is progressive and fatal, starting with changes to memory and behavior and ending when the brain can no longer control the body’s physical functions like heartbeat and breathing.
“In my 13 years at Emory, I’ve taken care of two children with SSPE, and that is two more than I ever want to take care of,” said Andi Shane, MD, an infectious disease specialist at Emory and Children’s Healthcare of Atlanta. Shane said the children she treated were not vaccinated because they came from poor countries that didn’t offer the shot.
Even when the shot is available, not everyone can be vaccinated. Babies are most vulnerable because they don’t get their first dose of the measles vaccine until their first birthday. Some children and adults with compromised immune function, such as those with cancer and on chemotherapy, can’t be vaccinated because the vaccine makes use of a live, but weakened, version of the virus. These groups are particularly vulnerable to such an infection and more likely to have severe complications, too.
The surge of new cases in the U.S. parallels a rise in measles around the world. Nearly 365,000 measles cases were reported globally this year, about three times as many as were reported in the first half of 2018.
In late August, the World Health Organization declared that four European countries had lost their measles elimination status: Albania, the Czech Republic, Greece, and the United Kingdom.
Experts are warning that if measles is reestablished in the U.S., a host of other health problems will come with it.
“Measles is the canary in the coal mine in identifying a problem in your immunization program. That’s the first disease you’re going to see,” Orenstein says. He adds that we’re likely to see increases in other preventable diseases as rates of other vaccinations slide.
There’s another reason to worry about more illnesses after measles. That’s because the measles virus is thought to erase the immune system’s memory of past infections. That means immune cells can’t identify and quickly stop germs before they make us sick.
A 2015 study in the journal Science found that as measles vaccine rates increase in a country, the rates of other non-measles infections in kids drop right along with it.
This “immune amnesia continues” for 2 to 3 years after a person is infected.