Measles usually kills your immune memory, but it weirdly helped WWI soldiers bounce back faster from the 1918 flu.
March 20, 2026
Original Paper
Recent measles virus infection increased the severity of infectious disease in WWI with the exception of pandemic influenza
medRxiv · 10.64898/2026.03.16.26348545
The Takeaway
Measles is famous for causing 'immune amnesia,' a state where the body forgets how to fight other diseases, typically making survivors more vulnerable for years. This study of historical military records found a bizarre exception: soldiers who had recently survived measles were actually hospitalised for significantly shorter periods when they caught the Spanish Flu, overturning the assumption that measles makes all subsequent infections worse.
From the abstract
Background: In World War 1 (WW1) outbreaks of measles were associated with high case fatality rates amongst soldiers. Recent studies have shown that survivors of acute measles can also develop immune amnesia, increasing their susceptibility to other infections. However, the impact of prior measles infection on infectious diseases during WWI remains unclear. Methods: Here, we create a searchable database documenting the medical history of 1,569 individuals from the Australian, New Zealand, and Ca