Child virus-related paralysis falls off script, baffles CDC

in September, MedPage Today reported an increase in cases of enterovirus D68 (EV-D68) among children in the United States. This report tracks what has happened since the first report.

The CDC issued an alert to EV-D68 in its Health Alert Network Advisory, which announced in September that cases were on the rise. Later that month, authorities reported surveillance data showing that rhinoviruses, enteroviruses, or both were detected in 26.4% of children and adolescents with acute respiratory illness requiring emergency treatment or hospitalization. did. Of these, 260 (17.4%) tested positive for his EV-D68, a rate he rose to 56% by mid-August.

The most significant concern was the potential acute flaccid myelitis (AFM) threat. This is a rare condition associated with EV-D68 that primarily affects the central nervous system in children, weakening muscles and reflexes and can lead to paralysis. Previous AFM incidence spiked in even-numbered years (2014, 2016, and 2018).

However, as of December 1, 2022, the CDC reported that AFM has not surged as expected.

“Despite the increased circulation and transmission of enterovirus D68, AFM cases will remain low in 2022,” said Janell Routh, M.D., Ph.D., who leads the AFM and National Polio Teams in the CDC’s Viral Diseases Division. said..

“This is the first time such a large disconnect between EV-D68 and AFM has been observed since the link was noted in 2014,” she said in an email. MedPage TodayRouth noted that the CDC’s 30 confirmed cases of AFM so far this year are similar to the number in other non-event years.

“Enteroviruses tend to circulate in late summer and early fall, so we don’t expect to see an increase in AFM later this year,” Routh added. It has been seen in the winter months of 2022 through 2022, so the CDC remains vigilant.”

“Right now, nobody knows the answer to this,” Routh said, as to why the biennial pattern wasn’t maintained. MedPage Today“Generally, it could be changes in viruses, host factors, or other cofactors that have been altered this year to alter the course of AFM,” she suggested.

Amy Moore, M.D., Ph.D., of the Ohio State Wexner Medical Center in Columbus, who treats patients with AFM, agreed the decline was puzzling. are affected, but these are not the numbers we expected given that children are back in school and masks are not mandatory.

The historical pattern of AFM certainly justified the caveat. AFM has been tracked by the CDC since August 2014. Between December he reported 120 cases in 34 states. The following year there were 22 reports, and in 2016 it rose again to 153.

In 2017, it decreased again to 38 cases. Then in 2018 he increased to 238.

Expectations for a surge in 2020 were also high. In August of that year, the CDC warned at a press conference that a life-threatening outbreak of acute flaccid myelitis was expected. In particular, the CDC was concerned that cases would be confused with he COVID-19.

“AFM can progress rapidly, patients can become paralyzed over the course of hours or days, and may require a ventilator to help them breathe,” the CDC said at the time. Director Robert Redfield, MD, warned during the briefing: “Some patients are permanently disabled… The virus that most commonly causes the condition, enterovirus D68, occurs on a two-year cycle. This means it will circulate at the same time as influenza and other infections, including COVID-19, and could become another outbreak that clinicians, parents, and children will have to deal with. there is.

However, the CDC’s 2020 surveillance reported 33 AFM cases in 2020, which is lower than expected.

“The low numbers are due to the use of masks and the lack of ‘direct’ activity due to COVID,” Moore said. MedPage Today“This trend was also seen with RSV. [respiratory syncytial virus] and flu. ”

Whether the biennial pattern is predictive is currently unknown.

From 2014 through December 1, 2022, CDC reported a total of 709 cases of AFM.

This rare but very serious case of neurological condition is consistent with respiratory disease caused by EV-D68, an antibody found in the mucus and spinal fluid of some AFM patients.

Researchers recently reopened the case of a boy who died of suspected AFM in 2008 and found EV-D68 RNA in the anterior horn neurons of his spinal cord.They reported their findings earlier this year New England Journal of Medicine“These findings support the notion that EV-D68 infection is the cause of AFM. The pathogenesis of AFM involves a combination of direct effects of viral infection and local inflammatory damage to spinal motor neurons. They may be involved.”

Research is ongoing to better understand the causes and treatments for the condition.

“Right now, the CDC is finishing collecting data on confirmed cases, and we’ll see how it compares to cases from previous years,” Routh said. MedPage Today“Our partners will investigate how viruses interact with animal models of AFM. We are collaborating with other institutions and academic centers around the country to better understand AFM.” I am continuing.”