CDC warns of possible acute flaccid myelitis spike in fall

Boy in wheelchair on balcony
Boy in wheelchair on balcony

Kari Hoglund / iStock

As the nation continues to grapple with COVID-19, Robert Redfield, MD, the director of the Centers for Disease Control and Prevention (CDC) warned US parents today that children will likely also be at increased risk this year for acute flaccid myelitis, or AFM, a mysterious, polio-like illness that seems to cause outbreaks in the United States every 2 years.

Though rarely fatal, AFM can cause permanent paralysis in patients and requires prompt hospitalization. There is no treatment or prevention for the neurologic manifestations, which are most probably caused by enteroviruses, particularly enterovirus-D68 (EV-D68).

"AFM is a priority for the CDC, as we expect an outbreak this year," said Redfield during a media briefing today. Redfield said patients experience sudden arm or leg paralysis following a fever or respiratory illness, and symptoms develop quickly over hours and days. 

"The virus comes in 2-year cycles, it will be circulating the same time as flu and COVID-19," Redfield said. "We do not know how the COVID 19 pandemic and social distancing measures will affect AFM; cases may be fewer, or outbreak could be delayed."

But regardless, Redfield and Thomas Clark, MD, deputy director of CDC's division of viral   diseases, urged parents and clinicians to immediately seek care for and hospitalize patients, and said they fear parents will be hesitant to seek medical care during the pandemic.

"We do not know why some children get AFM," said Clark, "And unfortunately, many kids will have permanent disability. But we are worried that parents won't take their child to the doctor because of COVID-19."

Almost a fourth require mechanical ventilation

Since 2014, the CDC has monitored AFM activity after the country saw its first outbreak of 120 cases. In 2016, CDC tracked 153 cases, and in 2018 officials confirmed 238 cases. Cases usually spike between August and November

Today the CDC published in Morbidity and Mortality Weekly Report a new Vital Signs report on the clinical characteristics of AFM cases in 2018. Among the 238 patients, the median age was 5.3 years.

The vast majority (86%) had symptom onset during August to November. Six days before limb weakness and paralysis onset, 92% of patients reported having a fever, respiratory illness, or both. Though limb weakness and paralysis is the most common symptom of AFM, half of patents (52%) also had gait difficulty, or neck or back pain (47%).

Overall, 98% of patients were hospitalized, 54% were admitted to an intensive care unit, and 23% required endotracheal intubation and mechanical ventilation, the report said.

"Non-COVID-19 emergency department visits declined in 2020, and the pandemic could possibly contribute to delays in care or to an increased proportion of clinical evaluations taking place via telephone or telemedicine," the authors concluded. "During this time, it will be critical for parents and clinicians to be aware of signs and symptoms suggestive of AFM and maintain vigilance for this condition during 2020."

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