Two new studies show that scientists have figured out why children stricken with the highly infectious disease measles often catch other maladies afterward - and the answer shows that measles is more dangerous than doctors had realized.

Measles resets the patient's immune system to an immature state like a baby's, wiping out immunity the child had built up to other diseases.  The studies published by British and American researchers suggest terrible implications for health care workers who are already battling a rise in anti-vaxxer nonsense that has led to measles outbreaks around the world.  If this trend of mistrust in medical knowledge continues, caregivers are going to have their hands full dealing with parallel outbreaks of other dangerous diseases such as flu, diphtheria, and tuberculosis that could have easily been avoided.

"The (measles) virus is much more deleterious than we realized, which means the vaccine is that much more valuable," said Dr. Stephen Elledge, a geneticist and researcher at the US Howard Hughes Medical Institute who co-led the American study. 

His team discovered how measles destroyed between 11 and 73 percent of the children's protective antibodies that were built up by encounters with other infections.  With those antibodies wiped out, children are vulnerable to reinfections of diseases they had already beaten.

"This… is a direct demonstration in humans of 'immunological amnesia', where the immune system forgets how to respond to infections encountered before," said Dr. Velislava Petrova of Britain's Wellcome Sanger Institute and Cambridge University, who co-led the British study.