For some time, doctors have known that contracting measles can weaken the immune system for months, placing people, especially kids, at greater risk for potentially fatal infection by a host of germs, CBC News reports.
However, scientists have recently discovered that this vulnerable period goes on considerably longer than previously thought — up to three years. So, of course, this means that the benefit of avoiding measles also extends longer than was previously known. Another bonus: Researchers found that deaths from other infectious disease dropped after measles vaccination campaigns.
While measles has always been a rather sophisticated disease, it employs a rather sly trick that scientists had suspected for some time, but weren’t able to demonstrate. Measles gives the immune system amnesia, effectively making it “forget” how to fight scores of opportunistic illness, thus giving them an invitation to the party, according to this article by Tara Haelle.
It’s while the immune system is in this state that opportunistic infections like pneumonia or diarrhea can barge in and create havoc, even after a person has recovered from the measles.
Doctors now say the work is a clarion call to parents who don’t immunize their kids due to unfounded fears about a link between vaccines and autism, CBC News reports.
“The message is clear,” said Dr. Richard Wenzel, an infectious disease specialist at Virginia Commonwealth University. He was not involved in the study. The vaccine is safe and effective against measles, he added, and it may save a child’s life by helping to guard against other infections.
In preventing measles, “you preserve your ability to fight off all of these other infections,” said Michael Mina, a medical student at Emory University who led the study while at Princeton University, per CBC News.
Earlier this year, a measles outbreak tied to Disneyland that sickened 147 people in the U.S., including 131 in California, stirred debate. Infections also made their way to Mexico and Canada, sickening 159 people in Quebec.
Many of the people who fell sick weren’t immunized either due to age or personal reasons.
Marked by fever, cough, and a blotchy rash, measles had been successfully eliminated in the U.S. for over a decade due to vaccination efforts being promoted aggressively, CBC News reports. Sometimes outbreaks crop up when Americans or foreign visitors are infected overseas and then spread the virus among people who aren’t vaccinated.
For this latest study, an international team of researchers analyzed measles cases and death rates from other infections prior to and after widespread measles vaccination campaigns in the U.S., England and Wales, and Denmark.
In all of the countries, measles cases declined after vaccinations. Deaths from infections that weren’t measles also dropped. In the U.S., deaths from infections such as respiratory or diarrhea-type disease fell from 18 per 100,000 prior to vaccination to six per 100,000 after vaccinations. Researchers say the drop in measles cases is due to the introduction of the vaccine.
The team used mathematical modeling and found that the immune system took two to three years to rebuild itself after getting measles.
While vaccination was certainly important, other factors played a role. Better nutrition and smaller family size may also explain the drop in non-measles related infections, said Dr. James Cherry, a pediatric infectious disease expert at the University of California, Los Angeles. Cherry had no role in the study.
Other researchers who weren’t involved in the work questioned whether fewer deaths as measles cases declined may have had more to do with better nutrition and smaller family size than with prolonged immune suppression, Stuff reported. Mina said the team team didn’t see the same effect with rubella (measles), and this suggests that wasn’t the case.
Others were somewhat dubious about the paper’s assertion regarding years of suppression,saying it was plausible, but that they couldn’t comment on the mathematical models the group used. Diane Griffin, a microbiologist and immunologist at Johns Hopkins University in Baltimore, said she didn’t think it was clear that “immunologic amnesia” was an underlying cause.
“I do not think the mechanism or mechanisms are understood,” she said.
Paul Duprex, a virologist at Boston University and a co-author on earlier research in macaques, said that the research, although mathematically dense, was “a really neat paper” that should remind people of the importance of vaccinating children against measles, which killed about 145,000 people around the world in 2013.
Before the advent of vaccines, when everyone got measles, he added, many more kids fell prey to secondary infections.
“After the introduction of the vaccine, that didn’t happen,” he said. “Measles is not a disease that doesn’t cause trouble.”
The study was released by the journal Science on Thursday, and was funded by the Bill and Melinda Gates Foundation and federal grants.
