Research shows it can basically wipe your immune system's "memory."

Measles was deemed eliminated from the US in 2000, according to the Centers for Disease Control and Prevention. But recently—as in, the past five years—the disease become a growing concern due to outbreaks across the country. The largest outbreak the US has seen since 2000 happened even just a few months ago, due to lessened vaccination rates.

The infectious viral disease itself, which manifests as a rash of red spots, fever, cough, and watery eyes, can cause long-term disabilities and can even be fatal, especially in cases of individuals with already compromised immune systems. However, two new studies published Thursday have found that measles can also have serious long-term implications on our immune systems, basically causing “immune amnesia” by destroying antibodies that help protect us from other illnesses we were previously immune to.

For one study, published in the journal Science, Harvard Medical School researchers examined blood samples taken from children before and after getting measles, and before and after getting the measles vaccination. Those who had been infected with measles experienced a loss of 11 to 73 percent of their protective antibodies, while the immune systems of those who were vaccinated were not impacted at all.

Ultimately, the study's researchers concluded that the illness can undo any protection an individual has against diseases—ranging from the flu to tuberculosis—even if they are vaccinated against them. At the societal level, this could have a sweeping impact on overall health, as spikes of other illnesses will be likely after a measles outbreak, per the study.

“The biggest takeaway of this study is that measles is really much more detrimental to the immune system and overall childhood health than we had previously recognized,”  Michael Mina, MD, PhD, assistant professor of epidemiology at Harvard T. H. Chan School of Public Health and one of the study's lead authors, tells Health.

“It not only destroys overall immune function for a few weeks as children recover from the measles virus – something that has been known for a long time – but this study shows that it also prevents children’s ability to defend against pathogens they should have been equipped to deal with over the long term," he says. "This study really drives home the real importance of measles vaccination.”

The other study, published in the journal Science Immunology and conducted by researchers in Europe, came to an almost identical conclusion: "The team showed for the first time that measles resets the human immune system back to an immature baby-like state with only limited ability to respond to new infections," read a press release from the Wellcome Sanger Institute, who participated in the study.

The good news is, eventually an individual’s immunities will rebuild, but it might involve them having to be re-exposed to the illness. For instance, if they once had immunity to a certain type of flu strain after an infection, they will probably have to get it again to regain that immunity.

Dr. Mina explains that the measles situation is so concerning, because individuals—and even policymakers—seem to have a sort of “amnesia” themselves about just how bad the disease was before we virtually eliminated it. He believes this has resulted in “a bit of a reduction in the global urgency for measles elimination and, of course, has led to many parents decisions to not vaccinate their children because they do not think that measles is bad.” He points out that these recent findings make it “glaringly clear that a measles infection is not just a simple benign childhood infection.”

The aim for these findings is that they'll influence not only policy changes, but also individual choices to inspire widespread measles vaccinations. "I hope that the findings can help encourage some parents who are on the fence about vaccinating their children to really consider the harm that might be done if the child does come down with measles,” he says.

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