Measles Infection Causes 'Amnesia' In The Immune System, Study Finds

Nov 4, 2019
Originally published on October 31, 2019 5:18 pm

Researchers writing in the journal Science found that when kids get measles, it can cause “amnesia” in the immune system. 

In much of the Mountain West, measles vaccination rates are below the recommended 95% level.

The study focused on 77 kids in the Netherlands who didn’t get vaccinated against measles and then got sick during a recent outbreak. Blood samples showed that measles actually wiped out some of their immune system’s memory of how to fight other diseases. 

“So basically it’s a double whammy,” said Dr. Marian Rewers, a pediatric endocrinologist with the University of Colorado School of Medicine and a coauthor of the study. “If you don’t vaccinate your kid against measles, not only the kid may get infected -- and it’s not a pleasant or mild infection, it has a number of potential consequences in the brain and heart and other organs -- but also the infection lowers the immunity to all of the previous viruses and bacteria that this kid has been exposed to.”

The degree of so-called “immunological amnesia” varied by person, and by how sick they got. And while the total number of antibodies circulating in the blood did not decrease, the range of diseases those antibodies could detect dwindled. 

The children tended to lose between 30 and 40% of their antibody repertoire, though the full range stretched from 11% to 73%. In particular, their immune systems lost some of the ability to recognize the flu and a number of viruses often responsible for the common cold, plus enteroviruses, herpesviruses, some of which can cause Roseola, and RSV, a virus that can cause serious respiratory problems.

Rewers said rebuilding immune memory is not easy; it could require getting re-vaccinated, or getting sick all over again.

“And it takes some time. Sometimes it takes weeks, sometimes it takes years,” said Rewers. 

By contrast, the study found that kids who got vaccinated with the MMR vaccine did not get immune amnesia. Their immune systems stayed in tact, maintaining about 90% of their antibody repertoires. The findings echo those of a previous study that looked at thousands of children in the U.K. and U.S. and found that those who had gotten measles were more likely to get additional infections and require prescriptions than their vaccinated counterparts, an effect that lasted up to 5 years after measles infection.

Better MMR vaccination could prevent at least 120,000 deaths directly attributed to measles,  the authors of the more recent study write, but also “potentially hundreds of thousands of additional deaths attributable to lasting damage to the immune system.”

Dr. Amanda Dempsey, a pediatrician and researcher studying immunization, is also affiliated with the University of Colorado, but wasn’t involved in the study.

She said 77 children is likely a big enough sample size to make meaningful statistical comparisons, and that it’s likely the findings would also apply to Americans and not just the Dutch. But, she said, “such research would need to be replicated to be considered completely valid.”

“I think the main takeaway is that it underscores the importance of immunization,” said Dempsey. “The amnesia effect was not seen in the vaccinated group. So to me this is a direct refutation of people who use the ‘natural infection is better’ argument about why they don’t want to vaccinate.”

According to the National Conference of State Legislatures, Colorado, Utah and Idaho are among 17 states that allow parents to opt out of getting their children vaccinated due to personal or philosophical reasons. All Mountain West states allow exemption based on religious beliefs. 

This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Boise State Public Radio in Idaho, KUER in Salt Lake City, KUNR in Nevada and KRCC and KUNC in Colorado. 

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