Severe Respiratory Illness Associated with Rhinovirus during the EV-D68 Outbreak in the United States, August – November, 2014

Abstract

BACKGROUND

In 2014, a nationwide outbreak of severe respiratory illness occurred in the United States, primarily associated with enterovirus D-68 (EV-D68). A proportion of illness was associated with rhinoviruses and other enteroviruses, which we aimed to characterize further.

METHODS

Respiratory specimens from pediatric and adult patients with respiratory illness were submitted to CDC during August – November 2014. While initial laboratory testing focused on identification of EV-D68, the negative specimens were typed by molecular sequencing to identify additional enterovirus (EV) and rhinovirus (RV) types. Testing for other pathogens was not conducted. We compared available clinical and epidemiologic characteristics among patients with EV-D68 and RV species A-C identified.

RESULTS

Among 2629 typed specimens, 1012 were EV-D68 (39%) and 81 (3.1%) represented 24 other EV types; 968 were RVs (37%) covering 114 types and grouped into three human RV species (RV-A=446, RV-B=133, RV-C=389); and 568 (22%) had no RV or EV detected. EV-D68 was more frequently identified in patients presenting earlier in the investigation period. Among patients with EV-D68, RV-A, RV-B, or RV-C identified, the age distributions markedly differed. Clinical syndromes and ICU admissions by age were largely similar among those with EV-D68 and RV species.

CONCLUSIONS

RVs were commonly associated with severe respiratory illness, alongside EV-D68, during the nationwide outbreak. Clinical characteristics were largely similar among those with EV-D68, RV-A, RV-B, or RV-C. A better understanding of the epidemiology of RVs and EVs is needed to help inform development and use of diagnostic tests, therapeutics, and preventive measures.