How Measles Wipes out the Body's Immune Memory

Over the last decade, evidence has mounted that the measles vaccine protects in not one but two ways: Not only does it prevent the well-known acute illness with spots and fever that frequently sends children to the hospital, but it also appears to protect from other infections over the long term. 


How does this work?


Some researchers have suggested that the vaccine gives a general boost to the immune system. Others have hypothesized that the vaccine's extended protective effects stem from preventing measles infection itself. According to this theory, the virus can impair the body's immune memory, causing so-called immune amnesia. By protecting against measles infection, the vaccine prevents the body from losing or "forgetting" its immune memory and preserves its resistance to other infections.


Past research hinted at the effects of immune amnesia, showing that immune suppression following measles infection could last as long as two to three years. However, many scientists still debate which hypothesis is correct. Among the critical questions are: If immune amnesia is real, how exactly does it happen, and how severe is it?


Now, a study from an international team of researchers led by investigators at Harvard Medical School, Brigham and Women's Hospital and the Harvard T.H. Chan School of Public Health provides much-needed answers.