The New Vaccine Surveillance Network Report on Enterovirus D68 Infections

Anyone who has been following the outbreaks of Acute Flaccid Myelitis the last few years will likely think the following report is long overdue.

The report, Enterovirus D68–Associated Acute Respiratory Illness — New Vaccine Surveillance Network, United States, July–October,2017 and 2018, is especially welcome by those folks who are already convinced that AFM is associated with EV D68.

The New Vaccine Surveillance Network Report on Enterovirus D68 Infections

But wait, why was surveillance done through the New Vaccine Surveillance Network?

And for that matter, what is the New Vaccine Surveillance Network?

“The New Vaccine Surveillance Network (NVSN) includes study sites that focus on population-based surveillance and data collection on the use and impact of vaccines and the impact of vaccine policies. Since 2006, NVSN sites have conducted active, population-based surveillance for hospitalizations and outpatient visits associated with acute gastroenteritis (AGE) in children (2006-present). NVSN sites have conducted surveillance for acute respiratory illness (ARI) from 2000 to 2009, and again beginning in 2015.”

New Vaccine Surveillance Network (NVSN)

Before you start thinking that this means a new Enterovirus D68 vaccine is coming out soon, many NVSN studies have nothing to do with vaccines…

“NVSN supports broad-based surveillance and research projects for acute gastroenteritis and acute respiratory infections in areas with a population base of at least 500,000.”

New Vaccine Surveillance Network (NVSN) Overview

In addition to studies on the flu and pneumococcal disease, they have done studies on norovirus, coronavirus, human metapneumovirus, HPIV, RSV, and rhinovirus infections.

So what did they find out about Enterovirus D68 infections?

“Based on preliminary data, test results were positive for EV-D68 for two (0.08%) of 2,433 patients with ARI who were tested during 2017 and 358 (13.9%) of 2,579 tested during 2018. “

Enterovirus D68–Associated Acute Respiratory Illness — New Vaccine Surveillance Network, United States, July–October, 2017 and 2018

There were a lot more EV D68 infecions in 2018 than there were in 2017

And what does that mean?

Considering that we had “only” 33 confirmed cases of AFM in 16 states in 2017 and at least 223 confirmed cases of AFM in 41 states in 2018, the rise in EV-D68 cases seems to correlate with the rise in AFM.

“Although AFM is rare in the United States, these AFM surveillance data, along with the EV-D68 activity documented through NVSN, provide additional supporting evidence for a temporal association between EV-D68 respiratory illness and AFM. “

Enterovirus D68–Associated Acute Respiratory Illness — New Vaccine Surveillance Network, United States, July–October, 2017 and 2018

Again, few people are going to be surprised by this news…

So, what’s next?

You mean besides the 2019 AFM season?

More on Acute Flaccid Myelitis News


Acute Flaccid Myelitis Update

The latest update on acute flaccid myelitis, including case counts.

Breaking News – The CDC has updated the Acute Flaccid Myelitis (AFM) case counts. (see below).

These 223 confirmed cases are among the total of 374 reports that CDC received of patients under investigation.

We continue to get regular updates from the CDC about AFM.

CDC Telebriefing: Update on Acute Flaccid Myelitis (AFM) in the U.S.

Unfortunately, we aren’t getting the real answer we were looking for – how to stop the outbreak.

Acute Flaccid Myelitis Update

Since the last update, we have learned that:

  • the case count is up to 223 confirmed cases among 374 reports, with most cases being confirmed at this point (2018)
  • cases have been reported in 41 states (2018)
  • there have been 2 confirmed cases (NC and UT) among 15 reported cases so far this year (2019)

That means that we have clearly exceeded the last record of 149 cases in 2016.

There are also 49 confirmed cases and 28 cases under investigation in Canada since January 2018.

In other news:

  • the CSTE will be issuing issued a new statement on AFM reporting reaffirming that they “are confident state and local health departments are working closely with doctors to ensure suspected cases are reported.”
  • the CDC has posted updated treatment guidelines
  • an MMWR early release, Increase in Acute Flaccid Myelitis — United States, 2018,  will provide details on the first 80 cases of 2018 – but sound similar to what we have learned from outbreaks in 2014 and 2016…
  • the CDC is working with local and state health departments on better long term tracking of cases – something parents have been pushing for!
  • an AFM Task Force has been established to “bring together experts from a variety of scientific, medical, and public health disciplines to help solve this critical public health issue.”

Most importantly though, we again learned that the CDC still doesn’t feel that they have enough evidence to say that any one thing is causing AFM.

AFM Cases in the United States

In addition to this year’s cases, there were:

  • 33 confirmed cases in 16 states in 2017
  • 149 confirmed cases in 39 states in 2016
  • 22 confirmed cases in 17 states in 2015
  • 120 confirmed cases in 34 states in 2014 – with most of the cases being reported in California (24), Colorado (10), Utah (6), Massachusetts (9), Virginia (5), Indiana (5), and Illinois (4)

What’s next?

More on Acute Flaccid Myelitis News

Updated on March 27, 2019

What to Know About the Acute Flaccid Myelitis Investigations

Although you may just now be hearing about acute flaccid myelitis, it is important to understand that it isn’t new.

The rise in AFM cases began in 2014 and seem to occur every other year.
The rise in AFM cases began in 2014 and seem to occur every other year.

It wasn’t even new when we started to see an increased number of cases a few years ago.

What is new, is that we are seeing an increased number of cases.

Acute Flaccid Myelitis Timeline

AFM refers to acute (sudden onset) flaccid (droopy or loose muscles) myelitis (inflammation of the spinal cord) and it is a subtype of acute flaccid paralysis.

If that explanation doesn’t really help you, it might help to understand that paralytic polio, like AFM, is another subtype of acute flaccid paralysis.

“In August 2012, the California Department of Public Health (CDPH) was contacted by a San Francisco Bay area clinician who requested poliovirus testing for an unvaccinated man aged 29 years with acute flaccid paralysis (AFP) associated with anterior myelitis (i.e., evidence of inflammation of the spinal cord involving the grey matter including anterior horn cell bodies) and no history of international travel during the month before symptom onset. Within 2 weeks, CDPH had received reports of two additional cases of AFP with anterior myelitis of unknown etiology.”

Acute Flaccid Paralysis with Anterior Myelitis — California, June 2012–June 2014

That seems to be about when this started, in 2012.

Unfortunately, they didn’t figure out what was causing the paralysis in these three patients, despite extensive testing and more cases followed.

“To identify other cases of AFP with anterior myelitis and elucidate possible common etiologies, CDPH posted alerts in official communications for California local health departments during December 2012, July 2013, and February 2014.”

Among 23 cases, California health officials found that the median age of the patients was 10 years old, only two tested positive for EV-D68, although most did have a recent “an upper respiratory or gastrointestinal prodrome.”

“Acute flaccid paralysis (AFP) with anterior myelitis is not a reportable condition, and baseline rates of disease are unknown but are likely quite low. Data from 1992–1998 on children aged <15 years in California indicated an incidence of 1.4 AFP cases per 100,000 children per year and did not identify a single case of AFP with anterior myelitis.”

California wasn’t the only state with cases.

In 2014, there were at least 12 cases in Colorado and 11 in Utah.

“In response to the CDPH and CHCO reports, the CDC established a case definition for enhanced nationwide surveillance of AFM, which included individuals less than 21 years of age with acute flaccid limb weakness and MRI involvement of predominantly the gray matter of the spinal cord without identified etiology presenting after August 1, 2014.”

Messacar et al on Acute Flaccid Myelitis: A Clinical Review of US Cases 2012–2015

All together though, in 2014, once  the CDC began actively investigating cases, at least 120 cases were discovered in 34 states. The cases were associated with a large outbreak of EV-D68-associated respiratory illness, although they weren’t able to conclusively link those respiratory illnesses to the AFM cases.

Is there any evidence that there were a lot of cases before 2012?

Or that the CDC has dropped the ball and hasn’t been doing enough to investigate cases?

Not if you look at the timeline.

The CDC was involved very early, called for all cases to be reported, and is actively investigating those cases.

CDC activities include… using multiple research methods to further explore the potential association of AFM with possible causes as well as risk factors for AFM. This includes collaborating with experts to review MRI scans of people from the past 10 years to determine how many AFM cases occurred before 2014, updating treatment and management protocols, and engaging with several academic centers to conduct active surveillance simultaneously for both AFM and respiratory viruses.

CDC on the AFM Investigation

And if the first cases in California and Colorado triggered so much attention, isn’t it likely that any cases anywhere else would have done the same thing?

That makes it very unlikely that many cases were missed in earlier years.

  • EV-D68 first identified as a cause of respiratory tract infections – 1962
  • the first reports that EV-D68 could cause severe, even fatal respiratory disease – 2008
  • first AFM cases are discovered in California – August 2012
  • the Colorado Department of Public Health and Environment notifies the CDC about a cluster of AFM cases at Children’s Hospital Colorado and a joint investigation begins between the CDPH, CDC, and the physicians caring for the patients  – September 2014
  • the CDC issues a health advisory on Acute Neurologic Illness with Focal Limb Weakness of Unknown Etiology in Children and calls on local and state health departments to report patients to the CDC – September 2014
  • the CDC conducts a conference call on Neurologic Illness with Limb Weakness in Children, so that clinicians could learn about the latest situation, surveillance, and CDC clinical guidance for AFM testing, patient evaluation and case reporting – October 2014
  • the CDC posts Interim Considerations for Clinical Management – November 2014
  • 120 AFM cases in 34 states – 2014
  • Council of State and Territorial Epidemiologists AFM case definition adopted – June 2015
  • 22 AFM cases in 17 states – 2015
  • 149 AFM cases in 39 states – 2016
  • Council of State and Territorial Epidemiologists AFM case definition updated, which once again, recommends against adding AFM to the Nationally Notifiable Disease List – June 2017
  • 33 AFM cases in 16 states, including one death – 2017
  • CDC Telebriefing on Acute Flaccid Myelitis in the US with Dr. Nancy Messonnier, director of CDC’s National Center for Immunization and Respiratory Diseases – August 2018
  • 158 AFM cases confirmed in 36 states among 311 reported cases that are being investigated – 2018

The other issue that concerns many parents is why a definitive cause hasn’t yet been identified. And why don’t we have treatments or a cure yet?

“To date, no pathogen (germ) has been consistently detected in the patients’ spinal fluid; a pathogen detected in the spinal fluid would be good evidence to indicate the cause of AFM since this condition affects the spinal cord.”

CDC on AFM Investigation

Although enteroviruses can be difficult to detect in spinal fluid, it is important to keep in mind that isn’t the only thing that is keeping experts from declaring the investigation over and naming a cause, such as EV-D68.

“Among 41 patients whose upper respiratory tract samples were available for enterovirus/rhinovirus testing at CDC, 17 (41%) tested positive: eight (20%) for EV-D68 and nine (22%) for eight other enterovirus/rhinovirus types.”

Eyal Leshem on Notes from the Field: Acute Flaccid Myelitis Among Persons Aged ≤21 Years — United States, August 1–November 13, 2014

Another big issue is that EV-D68 has not been detected in every, or even most AMF patients, and many others have been found to have other enteroviral infections, including EV-A71.

Could it be a coincidence that investigators are finding these enteroviruses simply because it is the season for them to appear? That would mean something else is causing these kids to have AFM.

“During September–November 2016, 10 confirmed cases of AFM were reported in Washington. No common etiology or source of exposure was identified. Enterovirus-A71 was detected in one patient and EV-D68 in two patients, one of whom also tested positive for adenovirus.”

Acute Flaccid Myelitis Among Children — Washington, September–November 2016

While the focus is on EV-D68 as a cause and everyone wants an answer, no one wants the CDC or other investigators to be wrong.

That doesn’t mean that they should be overly cautious and waste time or resources once an answer is evident, but just that they should follow sound epidemiological principles, get the right answer, and help stop kids from getting AFM.

What’s Next for AFM?

There are still a lot of unknowns about AFM, but this is likely what we can expect in the coming months:

  • the CDC will continue to investigate all unconfirmed cases that have occurred this year, which can take about four weeks after a case is reported and all necessary information is sent in. Keep in mind that since we don’t know if the CDC has already received all of the information on the cases they are investigating, we don’t know when they will finish investigating any pending cases.
  • local or state health departments will likely reach out to treating physicians to get followup about AFM patients about two months after they developed limb weakness and then report this short-term follow-up data to the CDC. In general, the CDC does not seem to contact patients directly.

From the current investigation, information from outbreaks and cases over the previous years, and cases in other countries, we will hopefully get the answers we need soon to prevent and treat AFM.

During the COCA Call, the AFM Surveillance Team will discuss the activities CDC is conducting as part of its AFM investigation.
The AFM Surveillance Team will participate in a COCA Call in mid-November.

Maybe some of those answers will come during a Clinician Outreach and Communication Activity (COCA) Call on November 13, when members from the CDC Acute Flaccid Myelitis Surveillance Team discuss the “activities the CDC is conducting as part of its investigation into AFM.”

The fact that the CDC has an Acute Flaccid Myelitis Surveillance Team will be news and is hopefully reassuring to some folks…

This is also probably a good time to remind folks that funding for public health has been declining in recent years, even as we expect our public health officials to respond to more things and react more quickly to keep us all safe and healthy. Let’s make sure we fund our public health programs, including the CDC and NIH, so that they have all of the resources they need to address all of today’s public health challenges.

More on the Acute Flaccid Myelitis Timeline

Updated on December 10, 2018

Is Acute Flaccid Myelitis Contagious?

Do we really know whether or not acute flaccid myelitis is contagious or not?

Many people were surprised by a comment by Dr. Robert Redfield, the director of the Centers for Disease Control and Prevention, in an interview for “CBS This Morning,” during which he said that acute flaccid myelitis:

“doesn’t appear to be transmissible from human to human.”

Wait, then how do kids get it?

Is Acute Flaccid Myelitis Contagious?

Since we don’t actually know what causes AFM, it is certainly possible, although rather unlikely, that it is caused by something that is not communicable.

But remember, the leading theory is that AFM is caused by an enteroviral infection, either EV-D68 and EV-A71, as most kids develop symptoms shortly after they had viral symptoms, and these two viruses are most commonly identified.

And you are typically contagious when you are sick with an enteroviral infection.

So how can the CDC Director say that AFM “doesn’t appear to be transmissible from human to human?”

It is because even if the virus that causes AFM is communicable, you can’t actually catch AFM from someone.

adult child cooperation daylight
Wash your hands to help avoid viral infections. Photo by Andres Chaparro on Pexels.com

Just like polio.

While the polio virus itself is communicable, paralytic polio isn’t. You can’t catch paralytic polio. Instead, you can catch polio, and then you have the small chance that it develops into paralytic polio.

It may not sound like a big difference, but it is.

Just consider what might happen if AFM itself was contagious, and if most of the kids who were exposed to someone with AFM developed AFM themselves…

We would likely see a lot more cases of AFM, especially in clusters in homes, daycare centers, and schools.

Instead, most cases seem to be isolated.

AFM Clusters

But aren’t there reports of clusters of AFM?

“In September 2016, an acute care hospital in Arizona notified the Maricopa County Department of Public Health (MCDPH) of a suspected case of AFM and subsequent cluster of 11 children who were evaluated with similar neurologic deficits; differential diagnoses included transverse myelitis and AFM.”

Notes from the Field: Cluster of Acute Flaccid Myelitis in Five Pediatric Patients — Maricopa County, Arizona, 2016

Yes, kind of.

But they aren’t clusters of epidemiological linked cases.

In Arizona, for example, only four of the 11 children were confirmed to have AFM and “no epidemiologic links were detected among the four patients.”

“In October 2016, Seattle Children’s Hospital notified the Washington State Department of Health (DOH) and CDC of a cluster of acute onset of limb weakness in children aged ≤14 years.”

Acute Flaccid Myelitis Among Children — Washington, September–November 2016

Similarly, at Seattle Children’s Hospital, the ten cases in their “cluster” had nothing in common, except for having prodromal respiratory or gastrointestinal symptoms about seven days before developing AFM symptoms.

It is likely that you see “clusters” at some hospitals simply because they are referral hospitals for a large region.

But even if we don’t know why some kids with these viral infections develop paralysis and other don’t, if they are the cause, then you wouldn’t develop AFM if you never actually had the virus.

“While we don’t know if it is effective in preventing AFM, washing your hands often with soap and water is one of the best ways to avoid getting sick and spreading germs to other people.”

About Acute Flaccid Myelitis

So handwashing and avoiding others who are sick is still the best strategy to try and avoid getting AFM.

And getting vaccinated against polio and using insect repellents can help you avoid other known causes of AFP – polio and West Nile virus.

More on Preventing AFM

The Case for Making AFM Reporting Mandatory

Do we really need to add AFM to the Nationally Notifiable Condition List? Will that mean mandatory reporting of all cases?

There have been 158 cases of acute flaccid myelitis (AFM) so far this year, with another 153 cases under investigation by the CDC and state and local health departments.

“Acute flaccid myelitis (AFM) is not nationally notifiable; CDC relies on clinician recognition and health department reporting of patients under investigation (PUIs) for AFM to learn more about AFM and what causes it.”

But could there be more cases?

The Case for Making AFM Reporting Mandatory

Although AFM isn’t yet a nationally notifiable disease,  120 other diseases are, from Anthrax and Botulism to Vibriosis and Zika virus disease.

The Nationally Reportable Disease List depends on state laws for any mandate to report.
The Nationally Notifiable Condition List depends on state laws for any mandate to report.

Who picks them?

The Council of State and Territorial Epidemiologists.

“Although AFP surveillance is commonly conducted in many countries currently still at risk for ongoing transmission of poliovirus, AFP is not a reportable condition in any U.S. state and routine surveillance and assessment for AFP is not performed. Therefore, understanding the baseline incidence and epidemiology of AFM and its public health impact in the United States is significantly limited.”

Revision to the Standardized Surveillance and Case Definition for Acute Flaccid Myelitis

Acute flaccid paralysis (AFP) isn’t a reportable disease in the United States either.

While many people would like AFM to be added to the the Nationally Notifiable Condition List, the CSTE has instead recommended that we:

  1. Utilize standard sources (e.g. reporting to a local or state public health department) for case ascertainment for acute flaccid myelitis (AFM), including clinician and laboratory reporting, reporting by hospitals, hospital discharge notes, neurology or infectious disease consult notes, MRI reports and images, outpatient records, and extracts from electronic medical records, etc.
  2. Utilize standardized criteria for case identification and classification for acute flaccid myelitis (AFM) but do not add AFM to the Nationally Notifiable Condition List . If requested by CDC, jurisdictions (e.g. States and Territories) conducting surveillance according to these methods may submit case information to CDC.
  3. Report cases as soon as possible and continue surveillance.
  4. Share data to “measure the burden of acute flaccid myelitis (AFM).”

And the CDC has agreed.

“CDC concurs with this position statement. We look forward to continuing to work with our jurisdictional partners to address this important public health issue. This standardized case definition provides an opportunity to better define the spectrum of illness seen with AFM and to determine baseline rates of AFM in the United States. During review of the position statement, a few minor edits were identified as necessary for clarification, and we are working with the author to make these changes.”

What would be the difference if AFM was added to the Nationally Notifiable Condition List?

For one thing, because the list of reportable conditions varies from state to state, it would provide a uniform case surveillance and case definition.

But we already have that in the CSTE Position Statement on Acute Flaccid Myelitis.

The big issue is that there is no federal law that actually mandates reporting for the diseases on the list! Or even to report them to the CDC.

“Each state has laws requiring certain diseases be reported at the state level, but it is voluntary for states to provide information or notifications to CDC at the federal level.”

CDC on Data Collection and Reporting

It is up to state laws – in each and every state.

“The legal basis for disease reporting is found at the state level, where inconsistent laws may differ in terms of which conditions are reportable and their reporting process.”

Brian Labus on Differences In Disease Reporting: An Analysis Of State Reportable Conditions And Their Relationship To The Nationally Notifiable Conditions List

So even if the Council of State and Territorial Epidemiologists added AFM to the Nationally Notifiable Condition List, you would then need each state to pass a law adding AFM to their lists of notifiable diseases.

“Currently AFM is not a reportable condition in Texas.”

TxDSHS on Acute Flaccid Myelitis

How long would that take?

Zika is on the Nationally Notifiable Condition List, but guess what, like AFM, it isn’t on the reportable condition list in many states…

Utah has already added AFM to its list of notifiable conditions. Has your state?
Utah, Washington and Colorado have already added AFM to their list of notifiable conditions. Has your state?

Want to get more cases of AFM reported to the CDC?

Let’s raise awareness about AFM and educate parents and health professionals to get all cases diagnosed, as they can then get reported to local and state health departments, who will then report them to the CDC.

Making AFM reporting mandatory might sound like a big deal, but will it really make any difference in getting kids diagnosed and treated?

“Ultimately, we would have to decide what the purpose of making something nationally notifiable is. We can investigate it just as well without that designation, and keeping things at the state level (for now) allows a lot more flexibility in how we define and investigate it. It might seem frustrating because it isn’t on the nationally-notifiable list, but that honestly doesn’t matter in terms of how we investigate things.”

Brian Labus, PhD, MPH

Cases still get investigated without being on the Nationally Notifiable Condition List.

Cases still get reported without being on the Nationally Notifiable Condition List.

And that’s good, because adding AFM to the Nationally Notifiable Condition List is not something that would happen overnight.

CP-CRE was added to the National Notifiable Disease List in 2018 at the 2017 CSTE annual meeting.
CP-CRE was added to the National Notifiable Condition List in 2018 at the 2017 CSTE annual meeting.

The CSTE would probably discuss it at their next meeting (next summer), and if approved, it would take effect at the beginning of the new year – January 2020. But then, then CDC has to get approval from the Office of Management and Budget (OMB) to actually get permission to start collecting the data on AFM for the Nationally Notifiable Condition List. All of that likely means that the earliest we would see “national” reporting for AFM would be sometime in 2022.

Does that mean we should jump on it now if it is going to take so long, or should we wait to figure out a definitive cause, and then put that on the Nationally Notifiable Condition List?

Whatever we do, remember that it still wouldn’t be mandated reporting unless each and every state actually passes a law mandating reporting of AFM cases to the CDC. Again, being on the Nationally Notifiable Condition List simply means that states are strongly encouraged to report their cases, as they do now. There are several diseases on the Nationally Notifiable Condition List that states never add to their own notifiable conditions list.

“It is voluntary that notifiable disease cases be reported to CDC by state and territorial jurisdictions (without direct personal identifiers) for nationwide aggregation and monitoring of disease data. Regular, frequent, timely information on individual cases is considered necessary to monitor disease trends, identify populations or geographic areas at high risk, formulate and assess prevention and control strategies, and formulate public health policies. The list of notifiable diseases varies over time and by state. The list of national notifiable diseases is reviewed and modified annually by the CSTE and CDC. Every national notifiable disease is not necessarily reportable in each state. In addition, not every state reportable condition is national notifiable.”

CDC on Data Collection and Reporting

Mostly, folks should understand that simply being on the Nationally Notifiable Condition List may not mean as much as they think it does.

“Although disease and condition reporting is mandated at the state, territory, and local levels by legislation or regulation, state and territory notification to CDC is voluntary. All U.S. state health departments, five territorial health departments, and two local health departments (New York City and District of Columbia) voluntarily notify CDC about national notifiable diseases and conditions that are reportable in their jurisdictions; the data in the case notifications that CDC receives are collected by staff working on reportable disease and condition surveillance systems in local, state, and territorial health departments.”

CDC on Data Collection and Reporting

And that epidemiologists at the local, state, and national level are working hard to identify all cases of AFM, which will hopefully help them figure out what is causing these cases, how to treat kids who are already affected, and how to prevent new cases.

They are identifying more and more cases of AFM even though few states have mandatory reporting, AFM isn’t on the Nationally Notifiable Condition List, and reporting of cases to the CDC is voluntary.

More on Making AFM Reporting Mandatory

Updated on December 10, 2018

What Causes Acute Flaccid Myelitis?

While acute flaccid myelitis is certainly mysterious, that doesn’t mean that we don’t know a lot about it already.

Most people are aware that there is a so-called “mystery illness” going around.

A “mystery illness” that is paralyzing some kids.

What’s so mysterious about it?

What is Acute Flaccid Myelitis?

Lots of things are mysterious about acute flaccid myelitis…

We don’t know exactly what causes it, who will get it, why they get it, or how to treat it, etc.

What do we know?

  • AFM is not new, although we are seeing more cases lately
  • AFM refers to acute (sudden onset) flaccid (droopy or loose muscles) myelitis (inflammation of the spinal cord) and it is a subtype of acute flaccid paralysis
  • most cases occur in children, with the ages of affected children ranging from 5 months to 20 years, although some adults have been affected
  • these children have a magnetic resonance image (MRI) showing a spinal cord lesion largely restricted to gray matter and spanning one or more vertebral segments
  • it is thought that AFM can be caused by viruses (polio, non-polio enteroviruses, West Nile virus, Japanese encephalitis virus, CMV, EBV, adenovirus, etc., environmental toxins, and genetic disorders, and although no common etiology has been found in these recent cases, most experts think that these cases are caused by a neuroinvasive infectious process, likely of viral etiology, including EV-D68 and EV-A71.
  • these cases of AFM are not thought to have a post-infectious immune-mediated etiology
  • cases are occurring sporadically – after 120 cases in 34 states in 2014, there were only 24 cases in 17 states in 2015, but then 149 cases in 39 states in 2016 and 33 cases in 16 states in 2017. And there have been at least 158 cases in 36 states in 2018, with another 153 cases under investigation.
  • outbreaks of EV-D68 and sporadic cases of AFM have also been seen in other countries recently, including Denmark, France, the Netherlands, Spain, Sweden and the United Kingdom (UK)
  • most cases occur in the late summer and early fall
  • most had symptoms of a preceding viral illness, including respiratory symptoms or diarrhea
  • some were unvaccinated
  • few were recently vaccinated
  • no specific treatments, including steroids, IVIG, plasmapheresis, interferon, and anti-viral medications, have been associated with better outcomes
  • some patients have recovered, while many others have persistent paralysis
  • there has been at least one death
  • some, but not all, were positive for enterovirus D68
  • in Colorado this year, 9 of 14 cases were linked to EV-A71 infections
  • although there was a national outbreak of EV-D68 in 2014 that coincided with the first AFM cases, we didn’t see the same kind of outbreak in the following years
  • AFM isn’t polio, Guillain-Barrésyndrome (GBS), acute disseminated encephalomyelitis (ADEM), or transverse myelitis
  • EV-D68 is not new, being first discovered in California in 1962

While that’s a lot of good information, for parents wanting to protect their kids and avoid AFM, there is some key information missing. Same for those wanting to help treat their kids who have or have had AFM.

So although some folks don’t like that it is being called a “mystery illness,” there is still a lot of mystery to it.

It is no mystery that AFM isn't associated with vaccines - experts review patient vaccination records.
It is no mystery that AFM isn’t associated with vaccines – experts review patient vaccination records.

But that doesn’t mean that experts aren’t working very hard to take all of the mystery out of AFM.

What Causes Acute Flaccid Myelitis?

Some experts are fairly sure that AFM is caused by an enteroviral infection, to the point that they hope that the CDC focuses work on an enteroviral vaccine.

Which enterovirus though?

At least two different enteroviral infections have been associated with AFM, including EV-D68 and EV-A71.

Why not just make a vaccine to prevent both?

You would first have to make a individual vaccines, before thinking about combining them, and you can’t just make any vaccine you want. If you could, we would have vaccines to protect us against RSV, malaria, HIV, and many other diseases.

Still, since EV-A71 also causes serious outbreaks of hand, foot, and mouth disease in some parts of the world, a vaccine has actually been in development for some time, and two are approved for use in China. That at least means making an EV-A71 vaccine is possible, although we would likely need to make our own.

Why did they make a vaccine for a virus that causes hand, foot, and mouth disease (HFMD)? Because unlike the HFMD that we are used to, which is typically caused by coxsackievirus A16 virus, another enterovirus, when caused by EV-A71, it can be deadly, as we have seen in outbreaks in Asia.

What about an EV-D68 vaccine?

While likely possible, since developing a new vaccine takes a lot of time, we want to be sure that is what is causing the outbreaks.

Do some kids not have either EV-D68 or EV-A71 because it just isn’t detected or because something else is causing them to have AFM? Possibly. One of the biggest issues that is troubling some experts though is that they have not detected these enteroviruses in the spinal cord fluid of many children, as you would expect if the viruses were causing the damage.

But even if these enteroviral infections are the cause, are there other risk factors that make some kids who get these enteroviral infections more predisposed to develop AFM, instead of more typical viral symptoms, like a cold or diarrhea?

And why are we seeing cases now? Did the virus, if that is the cause, just mutate into one that is more virulent?

Hopefully we get some more answers and a way to prevent, treat or cure AFM soon.

Until then, we can make sure we take steps to prevent the known causes of AFM, including polio (get vaccinated) and West Nile virus (use insect repellent), and wash hands properly to help avoid all other viral infections. You also want to get your flu vaccine! The flu can cause Guillain-Barré syndrome, which can also cause AFM.

“…is there any relationship between vaccination status and a developing acute flaccid myelitis? Meaning, are vaccines a risk factor? And the data so far says no, the overwhelming number of children who have gotten AFM have had no recent vaccination of any kind or vaccine exposure. These cases over these years have been happening before flu season and flu vaccination starts, which is one of the questions that comes up, and there hasn’t been any pattern to vaccine exposure of any kind in developing AFM. So far, we have not found a link between the two.”

Benjamin Greenberg, MD on 2018 Podcast on Acute Flaccid Myelitis

And remember, although there are many things we don’t know about AFM, we do know that vaccines do not cause AFM. It would also be great if everyone would get vaccinated so that the CDC and our local health departments could focus on health issues like AFM, instead of still battling measles outbreaks caused by folks who intentionally don’t vaccinate their kids.

What to Know About Acute Flaccid Myelitis

While it might be scary to think that there is a new condition out there that we don’t know everything about, parents should be reassured that experts are actively seeking the cause and a way to both prevent and treat AFM.

More on Acute Flaccid Myelitis

Updated on December 10, 2018