Measles infection could 'reset' a person's immune system, studies show

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The virus killed off B cells specific to other pathogens, allowing new, measles-specific memory B's to replace them.

Researchers already knew that measles affects the immune system, but these two studies confirm for the first time the mechanisms of immune amnesia.

However, many scientists still debate which hypothesis is correct.

The childhood disease measles causes long-term damage to the immune system which makes patients more vulnerable to other diseases, according to new research which used information gleaned from orthodox Dutch Protestants who don't vaccinate their children. That protection could dip even lower if some of the antibodies lost are potent defenses known as neutralizing antibodies.

"Imagine that your immunity against pathogens is like carrying around a book of photographs of criminals, and someone punched a bunch of holes in it", said Michael Mina, one of the study's primary authors, in a Harvard Medical School press release.

"It would then be much harder to recognise that criminal if you saw them, especially if the holes are punched over important features for recognition, like the eyes or mouth".

"The virus is much more deleterious than we realized, which means the vaccine is that much more valuable", said Stephen Elledge, a geneticist at Brigham and Women's Hospital, who led the study.

Normally, when we're exposed to an infection, the immune system's antibody factory kicks into high gear to recognize, remember and defend against a pathogen if it comes along again by making lots of fighter cells.

The findings help to explain why children often catch other infectious diseases after having measles, and underscore the dangers of growing resistance to childhood vaccination in some countries, according to two studies published simultaneously.

The Science Immunology study released Thursday investigated whether the character of the immune system changed after measles exposure. A related Focus by Duane Wesemann describes both studies in further detail.

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After measles, some children still show signs of immune suppression for up to five years although they appear healthy when their white blood cell counts are measured. 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.

Since 2018, however, the paper explains that reduced vaccination alone has led to a almost 300 percent increase in measles infections, and the impact on herd immunity could extend far beyond this one disease. Widespread vaccination has slashed the death toll.

However, measles is highly contagious and cases are rising again, with the UK's vaccination uptake dropping below the required level of 95% of the population. As a result, some Americans still view measles as relatively harmless-which, in addition to a risky uprising of anti-vaccine sentiment, has led some parents to decline shots for their children, contributing to a resurgence of preventable illness in the US and overseas.

This new discovery was made possible thanks to VirScan, a tool Elledge and Tomasz Kula, a PhD student in the Elledge Lab, developed in 2015. The technology tracks antibodies to thousands of viral and microbial antigens in the blood.

An analysis of blood from 77 unvaccinated children before and after a measles outbreak swept through their Netherlands community revealed that the virus erases the body's memory of previous pathogens.

When Kula examined an initial set of these samples, he found a striking drop in antibodies from other pathogens in the measles-infected children that "clearly suggested a direct effect on the immune system", the authors said.

The idea of measles-induced immune amnesia is not exactly new.

"If we slow or reverse public health gains when it comes to measles, this will have catastrophic consequences", he said.

These monkeys lost 40-60 percent of their antibodies against previously-encountered pathogens. "Measles is not as harmless of a disease as many people think". Utilizing information from a gathering of unvaccinated youngsters in the Netherlands, the two examinations uncovered what researchers have since a long time ago suspected: that the measles infection disables the resistant framework in a significant and enduring manner. 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.

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