Can measles “reset” the immune system’s previously built immunities? 

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Contact with the measles virus can lead to serious health complications, including the resetting of the immune systems of those infected through a process called immune amnesia.

This occurs because the measles virus can infect cells in both the respiratory and immune systems, specifically the memory cells, which are typically responsible for allowing one’s immune system to respond more quickly and efficiently to previously encountered antigens.

Pre-existing immunity to such pathogens are therefore eliminated with the elimination of the measles virus, with one study on unvaccinated children finding an elimination of up to 73% of antibodies. This immunosuppression can last 2 – 3 years.

Though the measles virus is highly infectious when unprotected, the MMR vaccine is 93% effective against measles at one dose and 97% at two.

As of May 4, 2025 there have been 16 measles cases in Oklahoma and more than 900 in the United States.

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Sources

• American Society for Microbiology Measles and Immune Amnesia
• Medline Plus Immune response
• Science.org Measles virus infection diminishes preexisting antibodies that offer protection from other pathogens
• Science.org Long-term measles-induced immunomodulation increases overall childhood infectious disease mortality
• CDC Measles Cases and Outbreaks
• CDC Measles Vaccination
• Oklahoma State Department of Health Measles