As I write, I imagine readers groaning at yet another measles story. But in early November 2019, in Portland, Oregon, Judy Guzman-Cottrill, DO, recently was groaning at yet another measles case.
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Dr. Guzman-Cottrill, a pediatric infectious diseases specialist at Doernbecher Children’s Hospital, recently shared details provided by the local health department:
An unimmunized child developed measles while traveling outside the county. The child may have exposed others at Portland International Airport, a medical center in Vancouver, and potentially at another children’s hospital in the area.
As of Nov. 7, 2019, 1,261 cases of measles from 31 states had been reported to the Centers for Disease Control and Prevention – more cases in a single year since 1992. The case in Portland added at least one to that total, although public officials warned that additional cases could occur Nov. 18th through Dec. 9 (given the incubation period). Like the child in Oregon, most of the individuals who developed measles nationwide in 2019 were unimmunized. At press time, from Jan. 1 to Dec. 5, 2019, 1,276 individual cases of measles have been confirmed in 31 states; CDC released measles reports monthly.
The reasons for refusal of measles vaccine vary, but historically, some parents have made a calculated risk. Measles is rare. Most children are vaccinated. My child will be protected by herd immunity. In some communities, that is no longer true, as we have seen in 2019.
Other parents have decided – erroneously – that measles infection is less risky than measles vaccine. We need to be able to tell them the facts. Thirty percent of individuals who contract measles will develop at least one complication, according to the Centers for Disease Control and Prevention. One in four will be hospitalized. While death from acute measles infection is uncommon, children remain at risk for sequelae months or years after the initial infection.
For example, measles is known to suppress the immune system, an effect that lasts for months or years after the initial infection. Practically, this means that once a child recovers from acute measles infection, he or she has an increased susceptibility to other infections that may last for years. Two studies published late in 2019 described the immune “amnesia” that occurs following measles infection. Essentially, the immune system forgets how to fight other pathogens, leaving children vulnerable to potentially life-threatening infections.
Michael Mina, MD, of the Harvard T.H. Chan School of Public Health, Boston, and colleagues measured the effects of measles infection on the immune system by studying blood samples taken from 77 unimmunized children in the Netherlands before and after measles infection.1 Two months after recovery from mild measles, children had lost a median of 33 % (range, 12%-73%) of preexisting antibodies against a range of common viruses and bacteria. The median loss was 40% after severe measles (range 11% to 62%). Similar changes were not observed after measles vaccine.
Dr. Kristina A. Bryant
A second group of researchers led by Velislava N. Petrova, PhD, of the Wellcome Sanger Institute in Cambridge, England, investigated genetic changes in 26 unvaccinated children from the Netherlands who previously had measles. They found that measles infection reduced the diversity of immune cells available to recognize and fight infections and depleted memory B cells, essentially returning the immune to a more immature state.2
Parents also need to know that children who develop measles are at risk for noninfectious complications.
Yes, SSPE is a rare, but it is not as rare as we once thought. In 2017, investigators in California described 17 cases of SSPE identified in that state between 1998 and 2005.3 The incidence of SSPE was 1 in 1,367 for children less than 5 years at the time of measles infection and 1 in 609 for children less than 12 months when they contracted the virus.
Dr. Guzman-Cottrill has seen a case of SSPE, and she hopes to never see another one. “He had been a healthy 11-year-old boy,” she recalled. “He played soccer and basketball and did well in school.” In the beginning, his symptoms were insidious and nonspecific, Dr. Guzman-Cottrill and colleagues wrote in a 2016 issue of Morbidity and Mortality Weekly Report.4 He started to struggle in school. He dozed off in the middle of meals. He started to drop things. Over a 4-month period, the boy developed progressive spasticity, became unable to eat or drink, and could no longer recognize or communicate with his family. “That’s when I met him,” Dr. Guzman-Cottrill said. “It was heartbreaking, and there was very little we could do for him except give the family a diagnosis. He eventually died in hospice care, nearly 4 years after his symptoms began.”
The boy had been infected with measles at 1 year of age while living in the Philippines. Dr. Guzman-Cottrill emphasized that this family had not refused measles immunization. The child had received a measles vaccine at 8 months of age, but a single vaccine at such a young age wasn’t enough to protect him.
We can hope for change in 2020, including improved immunization rates and a decline in measles cases. If that happens, measles will no longer be a hot topic in the news. We’ll likely never know what happens to the children infected in 2019, those who are facing the current cold and flu season with impaired immune systems. A decade or more will pass before we’ll know if anyone develops SSPE. For now, all we can do is wait … and worry.
Dr. Bryant is a pediatrician specializing in infectious diseases at the University of Louisville, Ky., and Norton Children’s Hospital, also in Louisville. Dr. Bryant had no relevant financial disclosures. Email her at pdnews@mdedge.com.
References
1. Science. 2019 Nov 1;366:599-606.
2. Science Immunology. 2019 Nov 1;4:eaay6125.