The Centers for Disease Control and Prevention (CDC) issued an alert on September 9 about the spread of a common childhood virus, the enterovirus D68, which most commonly leads to respiratory illness among children and can cause paralysis or muscle weakness in rare cases.
Those who get it have symptoms that are often mild but can then become severe. The enterovirus family is large, with polio also falling within it. Both the poliovirus and EV-D68 can invade the nervous system and cause muscle weakness.
EV-D68 can occasionally result in acute flaccid myelitis (AFM). This condition is characterized by inflammation in the neck region of the spinal cord. Some people who experience this illness have difficulty moving their arms. Other people experience weakness in all four extremities.
More EV-D68 cases this year among children
Around 10 percent of people diagnosed with EV-D68 developed AFM during a large outbreak in the United States in 2014. The condition is likely rarer than that, however, since not everyone gets tested for EV-D68.
AFM is a serious illness, as full recovery from it is rare. Although most patients with AFM improve to some extent, the process is often difficult and requires rehabilitation.
The CDC has identified more EV-D68 cases this year among kids with severe respiratory illness than in the past three years combined. A total of 84 such cases were recorded from March through August 4. That is a huge jump as the CDC identified only six such cases in 2019, 30 back in 2020, and only 16 in 2021. Those numbers are likely to be undercounted, however.
Thirteen cases of AFM have been confirmed in the U.S. this year as of September 2. According to the CDC, it is investigating 20 additional AFM cases. The agency has recorded spikes in EV-D68 cases in the past every other year. That happened in 2014, 2016, and 2018 before the COVID pandemic.
Cases are rising again because children are back in school
Dr. Benjamin Greenberg, a neurologist at UT Southwestern's O'Donnell Brain Institute and treats patients at Children's Health in Dallas, told NBC News that the pattern most likely appears because children can develop immunity when the enterovirus spreads. That leads to off years with higher population immunity. Once the immunity wanes, though, case numbers rise again.
Dr. Sarah Hopkins, a pediatric neurologist at Children's Hospital of Philadelphia, said that they thought this would happen in 2020 because they had the last spike in 2018. Hopkins noted that with mask-wearing and social distancing and all those things that limit the spread of a respiratory virus, they did not have that expected spike.
Greenberg added that cases are most likely increasing again this year because kids are back in school and other public spaces.
