CDC Expects 2020 Outbreak of Rare, Polio-Like Condition Mostly Affecting Children

August 5, 2020 Updated: August 5, 2020

The U.S. Centers for Disease Control and Prevention (CDC) said on Aug. 4 that it expects another outbreak this year of a rare, polio-like condition that mostly affects children.

The CDC has said it does not know what causes acute flaccid myelitis (AFM), which affects the nervous system and triggers weakness and even paralysis in one or more limbs. Cases of the condition have spiked every 2 years in the United States since 2014, affecting more Americans with each outbreak.

In 2018, 238 cases of AFM were reported to the CDC, up from 149 cases in 2016, and the largest outbreak since the CDC began surveillance in 2014. Most cases were in children at 94 percent.

CDC Director Dr. Robert Redfield warned last month that doctors and parents must be vigilant in recognizing symptoms, as the “serious paralytic condition” can progress quickly.

“[AFM] patients can become paralyzed over the course of hours or days and require ventilator to help them breathe. Some patients will be permanently disabled,” he said, noting the most patients develop sudden arm or leg weakness.

“Timing is critical for AFM,” he added. “Delays in AFM recognition and care can put patients at risk.”

The CDC has, since the 2018 outbreak, been able to better recognize the signs and symptoms of the condition and respond faster, Redfield said. Two years ago, the median age of AFM patients was 5 years and 58 percent were male.

“As we head into these critical next months, CDC is taking necessary steps to help clinicians better recognize signs and symptoms of AFM in children,” he said.

Other AFM symptoms include recent or current respiratory illness, fever, pain or numbness in the limb(s), gait difficulty, headache, back or neck pain, difficulty talking or swallowing, and neck or facial weakness, according to the agency.

Both Redfield and Thomas Clark, deputy director of the CDC’s Division of Viral Diseases, stressed the importance of seeking medical attention amid the ongoing COVID-19 pandemic if children display potential AFM symptoms.

“AFM is a priority for CDC as we prepare for a possible outbreak this year,” Clark said. “We are concerned that, in the midst of a COVID pandemic, that cases might not be recognized as AFM, or we are concerned that parents might be worried about taking their child to the doctor if they develop something as serious as limb weakness.”

One phenomenon researchers have observed is the illness is particularly prevalent between August and October, a period when many viruses commonly circulate, according to the CDC.

Responding to a question concerning school reopenings and a potential AFM outbreak this year, Redfield said that he wanted to stress that the condition is a “very rare occurrence.”

“I want to stress it’s a very rare event. It’s a very serious event when it occurs in a family. But at the same time, extremely rare event,” he said.

“We encourage parents to follow the recommendations set forward by their schools and their local public health jurisdictions and especially to emphasize now more than ever the careful handwashing, cough etiquette, sanitizing high-touch surfaces to help reduce the risk of all respiratory illnesses,” Clark added.

Reuters contributed to this report.