Experts warn measles infections can linger for years as outbreak continues to spread across the nation

As cases of the deadly measles virus continue to circulate around the country, experts warn that infection remains a danger to peoples’ health even years after initial illness.

There are now hundreds of cases confirmed in Texas, New Mexico, and 14 other states. Two people who had not received preventative vaccines have died amid the outbreak, including a child.

While most children recover from measles, the virus impacts the ability of the immune system to respond to infectious organisms that can cause disease in the future – such as bacteria, fungi, viruses and parasites.

“So whenever you get measles, you lose some of your immune memory. And the more severe your case of measles is, the longer it lasts, the more of your immune system is destroyed,” Stephen Elledge, a professor in the genetics department at Harvard Medical School, told NPR on Monday.

The immune system’s memory helps to fight viruses, but measles can destroy the cells that hold that memory. In a recent study, Elledge and his colleagues found that unvaccinated children had lost between 11 percent to 73 percent of their antibodies, that help to identify foreign substances.

Previous research published in the journal Science found that measles disables immune memory for up to three years.

“And when you lose that memory, then you’re no longer immune to that particular pathogen,” he said. “So the next time you get it, you’ve got to fight that battle all over again.”

The way to prevent this outcome, and measles infection, is through vaccination. Two dose of the measles-mumps-rubella vaccine are 97 percent effective against measles. Those who have been fully vaccinated have lifelong protection. For the rare breakthrough infections, which are more common in areas of high risk, it can fend off severe illness and complications.

In total, more than 300 cases have been reported across 16 states – a tally higher than all of last year’s cases – in the latest outbreak.

Only two of cases in the West Texas outbreak have been in vaccinated individuals, while 257 were in those who were unvaccinated or whose vaccination status was unknown. Most cases reported elsewhere were in people who were unvaccinated. In Atlanta, cases were confirmed in three unvaccinated family members. In New York City, neither of the patients had been vaccinated.

Although it remains unclear if cases in other states are linked to the Texas outbreak, data from health authorities shows they have been reported in California, Alaska, Washington, Florida, Georgia, Kentucky, Pennsylvania, Maryland, New Jersey, New York, Rhode Island and Vermont. However, state health officials have also reported cases in Michigan and Kansas.

Very few people who are vaccinated — about three out of 100 — will become infected if they are exposed to measles. A concern is that cases of the highly contagious virus could spread to other unvaccinated communities. That’s especially worrying as childhood vaccination rates fall.

“There’s no doubt that we will in the future see the long-term consequences of measles,” Dr. Adam Ratner, a pediatric infectious disease specialist in New York City, told NPR.