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). RVs and EVs can have clinically similar presentations and are indistinguishable from one another on multiplex assays often used in clinical settings. Upon further typing, some specimens have been positive for enterovirus D68 (EV-D68). Concurrently, pediatric acute respiratory illness sentinel surveillance sites are reporting a higher proportion of EV-D68 positivity in children who are RV/EV positive compared to previous years. Although it primarily causes acute respiratory illness, EV-D68 has been associated with acute flaccid myelitis (AFM), a rare but serious neurologic complication involving limb weakness.
The purpose of this Health Alert Network (HAN) Health Advisory is to
Background
RVs and EVs are both part of the Enterovirus genus. RVs are typically associated with acute respiratory illness (ARI), including asthma exacerbations. EVs can also cause ARI but are associated with other clinical presentations, such as febrile rash and neurologic illness, including aseptic meningitis, encephalitis, or AFM. EV-D68 has biologic and genomic similarities to RVs; respiratory symptoms are similar in patients infected with RVs and EV-D68. Common symptoms among hospitalized children with EV-D68 include cough, shortness of breath, and wheezing; fever is reported in approximately half of known cases. On rare occasions, EV-D68 may cause AFM. This rare but serious neurologic condition primarily affects children and typically presents with sudden limb weakness. There are no available vaccines or specific treatments for RV or EV, including EV-D68, and clinical care is supportive.
Because of genomic similarities between RVs and EVs, they are indistinguishable from one another on multiplex respiratory assays often used in clinical settings (i.e., assays used in local clinical laboratories and those in commercial reference laboratories). Differentiation between RV and EV and confirmation of a specific RV or EV type requires typing by molecular sequencing or by using an EV-D68-specific real-time reverse transcription-polymerase chain reaction (rRT-PCR) assay.
In the United States, RVs circulate year-round, with typical peaks in the spring and fall. The typical EV season is late summer and early fall; similarly, EV-D68 is thought to peak in late summer and early fall. In 2014, EV-D68 caused a nationwide outbreak of severe respiratory illness in the United States. Since then, U.S. surveillance has expanded and detected increased EV-D68 activity in the fall of 2016, 2018, and to a lesser degree in 2020. The relatively lower circulation in 2020 may reflect the use of COVID-19 pandemic infection mitigation measures, which are known to have interrupted the circulation of other respiratory viruses. Consistent with these annual trends, national numbers of AFM cases also had peaks in the fall of 2014, 2016, and 2018.
In 2018, when EV-D68 most recently circulated at high levels in the United States, the median age of children seeking emergency department or inpatient care for EV-D68-associated respiratory illness was approximately 3 years; however, all ages of children and adolescents can be affected. Children with a history of asthma or reactive airway disease may be more likely to require medical care, though children without a known history of asthma can also present with severe illness. EV-D68 in adults is less understood but is thought to be more commonly detected in patients with underlying conditions.
In August 2022, CDC was notified by healthcare providers and hospitals in several regions of the United States of increases in severe respiratory illness in children who also tested positive for RV/EV. Consistent with this, an increase in respiratory specimens positive for RV and/or EV was noted in the National Respiratory and Enteric Virus Surveillance System (NREVSS). In addition, CDC monitors EV-D68 detections across the New Vaccine Surveillance Network (NVSN), a platform of seven U.S. medical centers that perform active, prospective surveillance for pediatric acute respiratory illness. Between April—August 2022, EV-D68 was detected in some children and adolescents with ARI across all seven sites. The number of detections in July—August 2022 was greater than in the same period of the previous three years (2019, 2020, and 2021). As of August 30, 2022, CDC had not received increased reports of AFM cases with onset in 2022. However, increases in EV-D68 respiratory illnesses have typically preceded cases of AFM, indicating that increased vigilance for AFM in the coming weeks will be essential.
Coordinate with your state public health laboratory to submit specimens from possible cases of AFM to CDC for AFM and polio testing.
Note: At this time, CDC does not recommend submitting specimens associated with respiratory illness. However, specific state or local health departments may have additional guidance on specimen submission and testing.
SRHD contact: cdepi@srhd.org; 509-324-1442 phone, 509-324-3623 fax
