NEW YORK • Measles is far more dangerous than most people realise, new research shows.
The disease can cause a severe and sometimes deadly illness, but two new studies published last Thursday found that even when patients recover, the virus can inflict lasting harm on their immune systems.
The weakened immunity leaves a child vulnerable for several years to other dangerous infections such as flu and pneumonia.
The damage occurs because the virus kills cells that make antibodies, which are crucial to fighting infections. Scientists call the effect "immune amnesia".
During childhood - as colds, the flu, stomach bugs and other illnesses come and go - the immune system forms something akin to a memory that it uses to attack those germs if they try to invade again.
The measles virus erases that memory, leaving the patient prone to catching the diseases again.
The findings make the need for measles vaccination even more urgent, because it protects children against much more than the ailment, the researchers said.
"When parents say no to getting a measles vaccine, you're not just taking a risk of your kid getting measles, you're causing them to lose this amazing resource of defences they've built up over the years before measles, and that puts them at risk of catching other infections," said Dr Michael Mina of Harvard Medical School and Brigham and Women's Hospital.
He is the lead author of one of the new studies, published in the journal Science.
"You've got to watch your kid's back for a few more years," he added.
In fact, if a person who has received vaccinations for other diseases contracts measles, it may wipe out the protection those vaccines had provided. Re-vaccination could help restore the child's immunity, the researchers said.
The second study, by a different team, was published in Science Immunology.
"This is wonderful science," said Dr William Schaffner, an infectious disease expert at Vanderbilt University, who was not involved in the studies.
"These are two wonderfully complementary studies that have provided a basic immunologic understanding of a phenomenon that has been recognised for a long time, mainly that measles infection causes immune suppression."
The studies arrive amid heightened concern about measles, as outbreaks flare up in the United States and other developed countries.
Vaccines have largely eradicated the disease, but a growing number of parents have begun to refuse vaccination for their children.
Some claim religious reasons and some mistakenly fear a link to autism, based on research that has been discredited as fraudulent.
Globally, the measles vaccine is estimated to have saved 21 million lives between 2000 and 2017.
But there are still more than seven million cases and 100,000 deaths a year, many in developing countries where people lack access to the vaccine.
Most who die are children younger than five years.
"These elegant studies provide insights into immunological deficits following measles infections that have intrigued scientists for over 100 years," said Dr W. Ian Lipkin, director of the Centre for Infection and Immunity at Columbia University's Mailman School of Public Health.
"I agree that the findings also enhance the strength of the argument for vaccination."
But he added: "I don't think it's going to change vaccination rates because those decisions are irrational."