I wrote about the potential for a spike in cases of a rare illness called acute flaccid myelitis in August of 2020. The EV-D68 enteroviruses include the rhinoviruses and coxsackieviruses, as well as the echoviruses. The 12 enteroviruses species and their over 200 known serotypes are to blame for a wide range of diseases, including the common cold, hand, foot, and mouth disease. The rhinoviruses cause more infections than any otherviruses.

The CDC Health Alert Network advisory issued last week isn't a coincidence. As I explained in my earlier post, the phenomenon of amysm related to EV-D68, which can cause mild to severe weakness and even permanent paralysis in young children, first emerged in 2012 and has shown a fairly reproducible pattern.

Cases of AFM continued to be reported after 2012, and a pattern of late summer and early fall predominance was established. A Colorado outbreak in 2014 led to the development of a national surveillance program run by the CDC and significant spikes were again seen in 2016 and 2018. The numbers have remained relatively low, but there has been a consistent increase in yearly totals with each biennial bump. There were 120, 153, and 236 proven cases in 2014, 2016, and 2018 respectively, with many more suspected but unproven cases. In the intervening years, case totals have dropped dramatically, with each having less than 50 proven cases.

The pattern began to break down in 2020. There were 33 confirmed cases of the disease. The CDC was correct in issuing the warning, but there was already good reason to expect a low number of cases.

It is possible, perhaps even likely, that we will see many fewer cases than expected if continued social distancing and the use of masks reduce the risk of spreading EV-D68.

You were correct that it had something to do with the Pandemic. It will be one of the most unusual seasons I have ever experienced in the world of medicine. Children under the age of 2 years are more likely to have respiratory infections in the fall and winter.

Respiratory syncitial virus is the most common cause of respiratory illness in children. More than 2 million yearly outpatient visits and anywhere from 60,000 to 100,000 hospitalizations in children under the age of 5 years in the United States are caused by the disease. Premature infants and children with chronic lung or heart disease are at the highest risk of dying from respiratory syncytial virus.

Respiratory infections like non-RSV aren't uncommon. 20,000 infants and toddlers are put in the hospital every year in the United States because of human metapneumoviruses. The rhinoviruses can cause disease severe enough to necessitate an admission. By the end of a three year residency, many children with respiratory infections may have been diagnosed and treated.

They have always been busy, even though there have always been some fluctuations in how bad a particular season is. We've never seen anything like it before. At my hospital, we had very few admissions of the respiratory syncytial virus. We had almost no admissions to the hospital for the flu. We didn't have any admissions for classic and common infections of children.

I don't know what I was doing in 2020. I was able to help adult medicine colleagues who were overwhelmed at times by managing some younger adult patients with relatively mild COVID-19 infections or conditions not completely unfamiliar to a doctor. I don't want to be put in that situation again.

Thanks to the measures that were put in place to reduce the risk of COVID-19, there were few chances for EV-D68 to cause a disease. There were some spikes in the South in the summer of 2021, but it was a mild season. There were only 28 confirmed cases of the disease during the fall and winter of the year.

13 cases have been confirmed so far. There is a good chance that we will see a spike in cases this fall that will put us back on the historical track. As more and more people return to pre-pandemic behavior, the respiratory virus season will hit us hard. In the past two weeks, we have admitted more children with respiratory infections than in the previous year, and we will easily eclipse the previous year by the end of the year. We are not outliers.

The CDC alert states that cases of EV-D68 are being reported from all over the country.

Healthcare providers and hospitals in several regions of the United States notified the Centers for Disease Control and Prevention (CDC) during August 2022 about increases in pediatric hospitalizations in patients with severe respiratory illness who also tested positive for rhinovirus (RV) and/or enterovirus (EV)…Upon further typing, some specimens have been positive for enterovirus D68 (EV-D68).

Less than a hundred cases of EV-D68 were reported to the CDC as of August 4th, but that is more than the last three years combined. It is reasonable to assume that some of the respiratory infections in children have been caused by EV-D68. By the end of September, we will have a better idea of how bad the season is going to be, as weakness/paralysis can take up to four weeks to develop after the initial infections.

Stay on top of the situation. In the meantime, I will point out that the same methods used to reduce the risk of infections with the enteroviruses apply to the other causes of respiratory disease. Good hand hygiene at all times and masks and social separation are important for protecting children. Unfortunately there is no vaccine.