The Centers for Disease Control and Prevention (CDC) issued an official health advisory last Friday prompted by recent outbreaks of a respiratory illness caused by the enterovirus D68 (EV-D68).
The agency intended to alert health care providers and public health departments to an increase in respiratory infections caused by EV-D68 and to urge physicians to consider the virus a possible cause of acute severe respiratory illness in children.
Additionally, the CDC warned of a possible increase in cases of acute flaccid myelitis (AFM) due to the virus.
There are more than 300 strains of enterovirus that can cause different types of contagious illnesses, infecting 10 million to 30 million Americans every year, according to the Cleveland Clinic.
Most people experience mild symptoms, do not seek medical care, and are never tested for the enterovirus. These cases can resemble the common cold, causing a runny nose, sneezing, body aches, shortness of breath, wheezing, coughing, and fever.
Nevertheless, some iterations of the virus bear similarities to more serious versions, like the strain that causes polio. While EV-D68 is not the same enterovirus strain that causes polio, it has the potential to cause polio-like symptoms.
The EV-D68 strain was first discovered in 1962. At the time, it was not circulating much and resulted in a milder illness than it does today.
Over time, the virus strain changed and acquired the ability to kill neurons and damage the spinal cord, according to Dr. Benjamin Greenberg, a neurologist at UT Southwestern’s O’Donnell Brain Institute.
Although the EV-D68 most commonly leads to mild respiratory illness among children, the symptoms can sometimes become severe.
In children, the virus strain can occasionally result in AFM, which is characterized by inflammation in the spinal cord in the neck area, which can cause permanent weakness in the arms or possibly all four extremities. Experts believe the virus settles in the spinal fluid, which leads to AFM.
AFM symptoms can develop a few weeks after the child recovers from a respiratory infection and are similar to stroke symptoms, like arm or leg weakness, slurred speech, and facial drooping.
CDC cautions patients to seek medical attention if these symptoms appear.
During an outbreak in the U.S. in 2014, nearly 1,400 adults and children were hospitalized with severe respiratory infections due to EV-D68, and approximately 10% developed AFM. Fourteen people died from the virus.
Cases of AFM in children also spiked after EV-D68 outbreaks in 2016 and 2018.
The virus tends to reemerge every couple of years. Dr. Greenberg explained to NBC News that this pattern likely appears because children develop immunity to the enterovirus when it spreads, leading to “off years,” but once the immunity wanes, cases tick upwards again.
However, the expected spike in 2020 did not materialize, potentially because COVID-19-related public health responses hampered EV-D68’s spread.
Dr. Green noted that the at-risk population will be bigger in 2022 than in 2020 because fewer children have ever been exposed to the virus.
According to the Cleveland Clinic, a person’s immune system gets better at fighting off the virus with each exposure. Thus, adults with more exposure opportunities tend to have milder or no symptoms when exposed to EV-D68. Children are hit harder by the virus.
From March through August this year, CDC identified 84 EV-D68 cases among children with severe respiratory illness. That number is expected to rise in the coming months because students are returning to school and spending more time indoors with others, where the virus can be easily transmitted.
It lives in bodily fluids and can spread through airborne droplets when an infected person coughs or sneezes. It can also spread during diaper changes, kissing, or sharing eating utensils and cups.
Most EV-D68 cases appear between August and November, according to Dr. Keith Van Haren, an assistant neurology professor at Stanford University.
CDC stated in its health alert that as of September 2, there were 13 confirmed cases of AFM, and 20 more cases are being investigated.