Researchers at Harvard have found that the measles virus erases the body's memory of previous pathogens, effectively wiping its immunity memory.
Globally, measles affects more than 7 million people each year and causes more than 100,000 deaths. Reduced vaccination rates have led to a nearly 300% increase in measles infections since 2018.
Scientists had inferred a longer-term impact on the immune system because deaths from other infections were seen to go up after a measles outbreak, as virus directly attacks the immune system.
The virus eliminated between 11 and 73% of the children's protective antibodies, blood proteins responsible for remembering previous encounters with disease.
This left some of the children with immunity close to that of a newborn baby. In order to rebuild their defences, they will need to be exposed to numerous pathogens as they were in their infancy.
The research found that the MMR vaccine itself did not produce immune suppression, meaning that recipients get the benefit of lifelong immunity to measles infection without the damaging effects of natural infection.
To tackle previously unseen infections, the immune system relies on constantly pumping out a diverse range of immune cells, thousands of different varieties, each with slightly different receptors on their surfaces, with a collective ability to recognise almost any pathogen.
The immune system also creates long-lived memory cells, which remain permanently in circulation, allowing the body to rapidly recognise and eliminate previously encountered infections.
Measles, also known as rubella, is a respiratory disease characterized by a rash all over the body in addition to fever, runny nose, and cough. It is typically a childhood illness that can be complicated by ear infection or pneumonia.
The disease spreads through the air by respiratory droplets produced from coughing or sneezing.