Dr. Siegel: Why the mysterious condition AFM is making every parent worry

The younger our children are, and the more helpless and reliant on us they are, the more we worry about their health and safety. When my oldest child fell off of a 2-foot ledge at 9 months old, I worried for months afterward.

Even though I am a physician who knows the hard facts about illness and deals with them on a daily basis, I still worry irrationally about a mystery illness striking my children suddenly and robbing them of their health and strength and threatening their lives.

I am not alone. All parents worry the same way. It is a beautiful manifestation of our love for our children – we always want them out of harm’s way, but we know we can’t always control their environment.

This is why the mysterious condition Acute Flaccid Myelitis (AFM) scares us and why we worry about it. We hear the numbers – one or two cases per million people – and know the chances of getting it are remote. But then we see a child on the news, usually about 4 years old, who suddenly, after an upper respiratory infection, can’t bear her weight, or move her arms or legs with ease, and who may never regain her strength.

The Centers for Disease Control and Prevention (CDC) is helping the public understand the facts as it discovers them. It now has a full task force assigned to AFM and it is investigating cases and possible cases.

The numbers – 440 cases since 2014, with 116 confirmed in 31 states so far this year, and an additional 170 cases under investigation – are still quite small.

Dr. Thomas Clark, a medical epidemiologist at the CDC and the incident manager for the AFM outbreak, told me that the CDC is keeping an “open mind to causes” while actively considering infection, post-infection, and even remoter non-infectious possibilities including micro-toxins.

He was reassuring when he said that the number of cases, when compared to two years ago, “doesn’t seem to be on the increase this year.” Fortunately, AFM remains quite rare.

At the same time, there has been an accelerated response within the CDC and a push for the task force to bring in outside experts. “Our goal is to fill the knowledge gap with results in terms of the immune response, pathophysiology (how the illness progresses), virology, and how to treat it.” Currently there is no effective treatment for AFM beyond physical therapy.

The CDC has found three viruses – coxsackievirus A16, enterovirus A71 and enterovirus D68 – in the spinal fluid of four of the 440 patients confirmed to have AFM, which points to a likely cause in those cases.

Furthermore, the vast majority of the cases of AFM are occurring between August and October, when these and other respiratory viruses predominate; over 90 percent of these cases are preceded by a mild respiratory illness or fever consistent with a viral infection.

So even if the CDC can’t confirm it yet, it seems likely that the “outbreak” of AFM in these cases is a rare post-viral syndrome of common non-polio viruses; by the time the damage to the spinal cord occurs, evidence of the virus in the bodily fluids is already gone.

So, what can be done? These viruses are so common, and the manifestation of AFM is so rare and unpredictable, that typical precautionary practices like hand washing can’t prevent it. AFM doesn’t seem to be occurring in clusters, meaning that the condition itself is not contagious from one person to another.

Vaccines are in the works for two of the viruses with suspected links to AFM – enterovirus A71 and enterovirus D68.  The EV71 vaccine is already being used in China for hand-foot-and-mouth disease.

But for these or other vaccines that could possibly prevent AFM to be studied or produced in the U.S., scientists first would have to be fairly certain that these were the culprit strains of the current outbreak.

Dr. Clark told me that as an epidemiologist, he understands that when the cause remains unknown, the disease is scarier.

And so we worry.