Science with Jonathan Webb: Measles and its impact on our immune system

Measles Wipes Your Immune System's Memory, Increasing Vulnerability To Other Dangerous Diseases

Measles are easily preventable - one vaccination dose is 93% effective at preventing the disease.

"But what stunned us was the havoc caused among the so-called naive immune cells".

Children infected by the measles virus lose many B-cells trained to recognize familiar infections, the researchers found.

However, many scientists still debate which hypothesis is correct.

Two detailed studies of blood from unvaccinated Dutch children who contracted measles now reveal how such infections can also compromise the immune system for months or years afterward, causing the body to "forget" immunity it had developed to other pathogens in the past. They vaccinated a group of ferrets for the flu, exposed some of them to a measleslike virus, then tested to see whether the flu vaccine still worked. "Sometimes it takes weeks, sometimes it takes years", said Rewers.

As Federico Martinón-Torres, head of the Pediatrics Service and director of Pediatric Clinical, Infectological and Translational Research at the University Clinical Hospital of Santiago de Compostela, says, "some research, such as this one, has pointed out that immunization strengthens the system in general immune". It seems the measles virus essentially reduces its host's antibodies to other diseases, which makes a person more susceptible to infection. In addition, they have hypothesized that the extended protective effects of it come from the prevention of measles infection. Because when the measles virus attacks the organism, it defends itself against it, but ends up exhausted and even if the person is well - without spots and without fever - what he does not know is that he has stayed for a period of nearly three years without defenses for the next infection.

"Revaccination following measles could help to mitigate long-term suffering that might stem from immune amnesia and the increased susceptibility to other infections", the authors said.

'Vaccination protects you against more than just measles, ' he said. Measles leads to more than 100,000 deaths per year worldwide in unvaccinated communities.

On the other hand, says Jennifer Lighter, an infectious disease physician at New York University's Langone Health in New York City, "I think after you see your child that has measles, you wouldn't want your child to get other infections and to suffer needlessly". The technology tracks antibodies to thousands of viral and microbial antigens in the blood.

The Science paper looked at the diversity of antibodies in the bloodstream using a new technique called VirScan. The team discovered that specific immune memory cells that had been built up against other diseases, and were present before the measles virus infection, had disappeared from the children's blood. The researchers also compared the measurements to those of 115 uninfected children and adults.

The idea of measles-induced immune amnesia is not exactly new. "We show that measles directly causes the loss of protection to other infectious diseases." says Velislava Petrova, lead author.

These monkeys lost 40-60 percent of their antibodies against previously-encountered pathogens.

But in about 10% of the population, it's a much longer process.

Researchers then tested this "immunological amnesia" directly in ferrets, showing that infection with a measles-like virus reduced the level of flu antibodies in ferrets that had been previously vaccinated against flu. This study finds that measles also has the potential to weaken our body's existing immune response to other diseases, leaving us vulnerable to infections.

'Both projects show that measles gives your immune system a real hit, which basically re-sets it, ' he said. "Babies are more vulnerable to infections because their immune system is still maturing". He pointed out that "one of the misconceptions of measles that often fuels vaccine hesitancy is that it is a benign childhood illness". The results align with decades of research.

These findings reinforce the importance of vaccination against measles, Elledge said. "We were trying to figure out how VirScan worked with measles", Elledge says. "But would they have gotten it if they hadn't gotten measles?"

Yumei Leng and Mamie Li of the Elledge Lab are co-authors of the study.

Dr. Amesh Adalja is a senior scholar at the Johns Hopkins Center for Health Security in Baltimore.

This study was supported by the Value of Vaccination Research Network, Gates Foundation, National Institutes of Health (grants U24AI118633, R01DK032493, R21AI095981 and R01AI131228), European Union Seventh Framework Programme (grant 202063), Academy of Finland (grant 250114) and PREPARE Europe (EU FP7 grant 602525). He is an investigator at Howard Hughes Medical Institute in Chevy Chase, Md., and professor of genetics at Harvard Medical School in Boston.

Last Updated: October 31, 2019. To contact the author, please use the contact details within the article.



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