Measles mystery cracked

And the trend wasn't seen just in America, but when the vaccine went to England, the same results occurred, and even today when the measles vaccine is given in developing countries get the treatment.

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Doctors now think they've cracked the mystery and published their findings in the journal Science.

And the answer is actually somewhat simple.

According to NPR, children who get the vaccine are usually getting better overall health care, like antibiotics and other shots.

But there's a more complicated addition to the health care formula.

Researchers found that measles predisposes kids to other diseases for a few years, since it suppresses, and even erases, the immune system.

The example cited by NPR: if a child gets chicken pox when they're 4, the body knows how to fight it after the illness.  But if a child gets measles when they're 5, the immune system's "memory" is wiped on how to beat chicken pox, so the immune system has to be rebuilt after the measles exposure.

While the findings are still in the hypothesis stage, doctors say there is "compelling evidence" that measles affects the immune system for two or three years after beating the illness, Science magazine reported.