Measles weakens immune system up to three years

Children affected by measles may live with a suppressed immune systems for up to three years, not just one or two months as earlier thought, new research has revealed.

The measles virus is known to cast a deadly shadow upon children by temporarily suppressing their immune systems - leaving them highly susceptible to a host of other deadly diseases.

Measles may throw the body into a much longer-term state of "immune amnesia," where essential memory cells that protect the body against infectious diseases are partially wiped out, the findings of the current study showed.

"We already knew that measles attacks immune memory, and that it was immunosuppressive for a short amount of time. But this paper suggests that immune suppression lasts much longer than previously suspected," said study co-author C. Jessica Metcalf, assistant professor at Princeton University.

"In other words, if you get measles, three years down the road, you could die from something that you would not die from had you not been infected with measles," Metcalf said.

"Our findings suggest that measles vaccines have benefits that extend beyond just protecting against measles itself," lead author Michael Mina, a medical student at Emory University, said.

Mina wondered how quickly the immune system would become broadly protective again after measles attacks and went on to examine detailed population data available from the US, Britain, and Denmark.

The researchers looked at deaths among children between the ages of one and nine in Europe, and one and 14 in the United States, in both pre- and post-vaccine eras.

The research uncovered a very strong correlation between measles incidence and deaths from other diseases, allowing for a "lag period" averaging roughly 28 months after infection with measles.

This finding was consistent in all age groups across the three countries and also consistent in pre- and post-vaccine eras.

The study appeared in the journal Science.