November 30, 2022
An article by STAT investigates the mystery of the missing acute flaccid myelitis triggered by EV-D68 infection that pediatricians expected to drive an influx of children into the hospital. Like many other respiratory viruses, EV-D68 had dipped during COVID-19 and the accompanying mitigation measures. As summer was concluding, however, children began to be admitted to hospitals with signs of the infection. CDC set out an alert warning practitioners to watch for cases. But while the enterovirus D68 showed, the spike in AFM cases didn’t happen.
Those who study AFM and polio were described as “grateful but flummoxed.” In the decade prior to COVID-19, AFM cases spiked at two-year intervals. When children would begin presenting with EV-D68, a small number of those children would develop neurological disease and symptoms of paralysis after a brief lag. Enough time has lapsed this year, experts who study AFM say, that the sick children would have been evident by now if this were to be a big year for cases.
This year’s experience adds to the confusion around AFM cases. Circumstances around AFM cases triggered by the virus were believed to be clarifying. An article from May shared a discovery of EV-D68 RNA and protein in the spinal cord of a child who died from AFM. Things were looking up and conditions appeared to be set for 2022 to be a peak year to evaluate. The fact that it did not has left everyone with more questions.
Similarly, 2020 was expected to be a big year for AFM. COVID mitigation efforts, however, appeared to stave off cases. This was also true in 2021 and added to fears that 2022 would be a big year for EV-D68 to circulate and AFM to exceed the previous high of 2018. The case numbers do not bear that out, with 2022 resembling more off year than peak year.
Several theories are discussed with no definitive answer in sight. The CDC still urges caution as hospitals are overburdened with cases of RSV and flu, which also came back strong after COVID efforts were eased. The fear being that COVID may have altered the situation and the potential for a forceful comeback exists.
PIDS member Matthew Vogt, author of the article mentioned in the story, is quoted in the story saying, “We all thought the enterovirus D68 part was going to happen, and it did. And we then also all thought that the AFM part was going to happen, and it didn’t. And that part is just perplexing.” Also quoted are members Kevin Messacar and Megan Culler-Freeman. The latter said, “I think it just leaves us with a bunch of questions. Do we think it’s gone away? Do we need to worry about it potentially being worse in 2024? I’m not sure of the answers yet.”