Measles Infection Can Weaken Other Immunities

The measles infection can have a devasting impact on the body’s immune memory, eliminating up to 73% of viral and bacterial strains a person had previously been immune to, according to a new study in Science.

“Many of the deaths attributable to measles virus are caused by secondary infections because the virus infects and functionally impairs immune cells,” the authors of the study wrote.

Despite a measles vaccine, the disease continues to impact Americans who are not vaccinated against the disease. According to the CDC, there have been 1,261 cases of measles in 31 states in 2019 alone.

The study, led by investigators at Harvard Medical School (HMS), Brigham and Women’s Hospital and the Harvard T.H. Chan School of Public Health, evaluated the effect the measles virus can have on the body’s immune memory by studying 77 unvaccinated children before they contracted the natural measles virus infection and again two months after contracting the disease. 

Researchers found that the virus had wiped out anywhere from 11 to 73% of the different antibodies a person had previously had to fight disease-whether it was antibodies protecting against the influenza, herpes virus, or pneumonia.

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“The threat measles poses to people is much greater than we previously imagined,” Stephen Elledge, a senior author and Gregor Mendel Professor of Genetics and of Medicine in the Blavatnik Institute at HMS and Brigham and Women’s said in a release announcing the results. “We now understand the mechanism is a prolonged danger due to erasure of the immune memory, demonstrating that the measles vaccine is of even greater benefit than we knew.”

The latest study supports the idea of “immune amnesia” or the idea that the measles virus can partially obliterate immune memory the body has stored due to previously encountered pathogens, researchers said.

“This is the best evidence yet that immune amnesia exists and impacts our bona fide long-term immune memory,” first author Michael Mina, an assistant professor of epidemiology at the Harvard Chan School, said in the release.

Researchers found that patients can regain their immunity as they are re-exposed again to viruses and bacteria; however, that can take time and could leave a patient vulnerable to secondary infections after the measles infection.

One possible strategy to mitigate this could be having the patient undergo a round of booster shots of all previous vaccines after getting the measles virus.

“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.