After a measles infection, it takes time for these cells to repopulate. Researchers have known that measles’ toll on these cells weakens patients’ immune defenses, but they thought that vulnerability only lasted for a few weeks.
However, in a
2012 study, researchers noticed that this wasn’t true in macaque monkeys. Monkeys who had measles and recovered started producing new B-cells and T-cells about a month later. But the new cells only had memory for the measles virus, not for any of the other infections the monkeys had been exposed to previously. The monkeys’ immune systems had amnesia, and it left them vulnerable to infectious diseases that otherwise might not have been a problem.