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CDC: No Warning Issued for Acute Flaccid Myelitis in 2021

SciCheck Digest

The Centers for Disease Control and Prevention has been tracking outbreaks of acute flaccid myelitis — a serious condition mainly affecting children — since 2014. The CDC hasn’t seen a reason for concern this year, but Facebook posts have wrongly claimed that the agency has issued a “warning of polio-like outbreak” this fall. The claim seems to have originated from an outdated news article.

Full Story 

Acute flaccid myelitis, or AFM, is an uncommon but serious neurologic condition whose symptoms can look similar to those of polio. AFM can be caused by enteroviruses, which are common and usually cause mild illness. 

AFM affects the nervous system, specifically the area of the spinal cord called gray matter, which causes the muscles and reflexes in the body to become weak. Sudden onset of arm or leg weakness, loss of muscle tone and loss of reflexes are the most common symptoms. It can also lead to permanent paralysis.

More than 90% of AFM cases occur in young children.

The Centers for Disease Control and Prevention has been tracking AFM since 2014. Outbreak cases of AFM have occurred in the U.S. in 2014, 2016, 2018 and 2020.

The largest number of AFM cases occurred in 2018, when there were 238 confirmed cases in 42 states. In 2020, there were 32 confirmed cases out of 59 reported cases. In 2021, as of Aug. 31, there have been 15 confirmed cases of AFM in nine states out of 36 reported cases. 

Despite the lower numbers this year, posts on social media are wrongly claiming that the CDC is “warning of polio-like outbreak coming in children this fall.”

The claim seems to have originated from a year-old news article written by Sputnik, a state-owned Russian news service, on Aug. 4, 2020. The story — “CDC Warns of New Outbreak of Polio-Like Illness in Children Later This Year in US” – was correctly based on an actual CDC warning for the fall of 2020.

A year later on Aug. 19, Asian News International, a wire service, mistakenly posted a version of the outdated CDC warning, crediting Sputnik for the report. Zenger News, a Texas-based wire service, ran an article a day later with the headline, “US Warns Of Polio-Like Illness Outbreak In Four Months,” adding that its story was written “[w]ith inputs from ANI.”

Zenger News deleted the outdated article from its website and “terminated its relationship with ANI after this episode,” Zenger told us in an email.

But the inaccurate story remains on the ANI website. The claim also has been shared by other social media users, and publications in Florida, Georgia and Tennessee have reposted the article, wrongly attributing the article to Zenger.

The article that ran on Zenger – and those attributed to Zenger on other websites – claimed that on Aug. 17, the CDC “alerted of an expected outbreak of the polio-like disease Acute Flaccid Myelitis (AFM) in the next four months.”

But a spokesperson for the CDC’s AFM team — which maintains an official channel for AFM information — told us in an email that while monitoring the disease “remains a priority for CDC,” the CDC “has not issued an official warning such as a [Health Alert Network] or an [Epidemic Information Exchange] alert to clinicians in 2021.”

“At this time, CDC has not received reports of an increase in suspected cases of AFM,” the spokesperson said. “In collaboration with our partners, we continue to closely monitor the situation and are prepared to respond to any increase in cases. CDC’s AFM Team continues to work with state health departments and professional medical organizations to educate clinicians about AFM in case we do see an increase in cases this year. Early recognition and hospitalization of patients suspected to have AFM is critical, as AFM can lead to respiratory failure.”

The latest CDC alert for AFM came in August 2020, when the CDC anticipated a “peak year” in AFM cases, because “the disease has peaked every two years between August and November in the United States since 2014.”

The alert — which was the basis for the Sputnik story a year ago — also questioned how protective measures put in place for the COVID-19 pandemic would affect the circulation of viruses that can cause AFM, stating, “AFM cases may be fewer than expected or the outbreak may be delayed” if “social distancing measures decrease circulation of enteroviruses.”

In 2018, Robert R. Redfield, then director of the CDC, ordered the AFM Task Force to assist an investigation into the origin, treatments and outcomes of the disease.

The task force is working to learn why a few people develop AFM after having a virus. The CDC says since it doesn’t know what triggers AFM, “there is no specific action to take to prevent AFM.”

However, the CDC says, you can take steps to prevent getting sick from a virus by:

  • Washing your hands often with soap and water for at least 20 seconds.
  • Avoiding touching your face with unwashed hands.
  • Avoiding close contact with people who are sick.

There is no specific treatment for AFM, but a clinician who specializes in diseases such as AFM may recommend certain interventions on a case-by-case basis. 

Although the symptoms of polio and AFM look similar, none of the AFM cases in the U.S. have been caused by the poliovirus.

Poliomyelitis, or polio, is a disabling and life-threatening disease caused by the poliovirus. The virus spreads from person to person and can infect a person’s spinal cord, causing paralysis.

The first polio vaccine was available in the U.S. in 1955. Because of widespread vaccinations, the U.S. has been “polio-free since 1979,” according to the CDC.

Update, Sept. 10: Our original story incorrectly said that reports of an upcoming AFM outbreak seem to have originated from Zenger. We updated this story after getting a statement from Zenger News spokesman Nate Miller. The statement said: “The story in question was published by Asian News International, a wire service in India. Zenger carried it in syndication, in the same way other publishers carry wire services like the Associated Press and Reuters. Yahoo Finance carried the same piece, for instance (Google cache), and subsequently deleted it. 

Accordingly, neither Yahoo nor Zenger ‘killed’ the story. That responsibility lies with ANI. We decided to remove it from syndication, as did Yahoo and others.”

The statement continued: “A reader asked us to investigate the story’s claims, and we determined that the CDC hadn’t made a statement that was the basis of ANI’s reporting. ANI hasn’t retracted its story, which is still live on its website (Link). It appears ANI got its information from Sputnik, a Russian news service with a dubious reputation for accuracy (Link). Sputnik was reporting on a CDC release from 2020, not from this year (Link). Zenger terminated its relationship with ANI in late August. We place a high value on both accuracy in reporting and public transparency.” 

Update, Sept. 13: We have updated our article to provide more information about the origin of the claim – making it clear that Zenger picked up the story from ANI. Zenger told us that it terminated its relationship with ANI “more than two weeks before Zenger was contacted by FactCheck.org’s reporter.”

Editor’s note: FactCheck.org is one of several organizations working with Facebook to debunk misinformation shared on social media. Our previous stories can be found here.


The AFM team. Email from spokesperson sent to FactCheck.org. 3 Sept 2021.

Centers for Disease Control and Prevention. “About Acute Flaccid Myelitis.” Updated 29 Dec 2020.

Centers for Disease Control and Prevention. “Acute Flaccid Myelitis (AFM). Clinicians & Health Departments.” Accessed 9 Sep 2021.

Centers for Disease Control and Prevention. “AFM Cases and Outbreaks.” Updated 3 Sept 2021.

Centers for Disease Control and Prevention. “Causes of AFM.” Updated 29 Dec 2020.

Centers for Disease Control and Prevention. “Symptoms of AFM.” 29 Dec 2020.

Centers for Disease Control and Prevention. “Vaccines and Preventable Diseases.” Updated 4 May 2018.

Centers for Disease Control and Prevention. “Vaccines and Preventable Diseases – Polio.” Updated 4 May 2018.

Centers for Disease Control and Prevention. “Vital Signs of AFM.” Updated 11 Aug 2020.

Mayo Clinic. “Acute flaccid myelitis (AFM).” 22 Sept 2020.

Zenger News. “US Warns Of Polio-Like Illness Outbreak In Four Months.” Florida Star. 20 Aug 2021.

Zenger News. “US Warns Of Polio-Like Illness Outbreak In Four Months.” Tennessee Tribune. 20 Aug 2021.