Enterovirus D68 in a community hospital: A test-negative case-control study

Background: In August 2014, a large North American outbreak of enterovirus D68 (EV-D68) was observed in association with severe respiratory illnesses in children as well as a possible association with acute flaccid paralysis. The full spectrum of clinical illness associated with EV-D68 is not well known. Objective: To compare children positive and negative for EV-D68 presenting to a community hospital during the North American outbreak in the fall of 2014. Methods: Consecutive nasopharyngeal swabs obtained from children (<18 years old) presenting to a large community hospital with respiratory symptoms in the fall of 2014 were tested for EV-D68. We conducted a test-negative case-control study between EV-D68 positive and EV-D68 negative children to describe the clinical and outcome characteristics. Controls were limited to children who had a nasopharyngeal swab obtained. EV-D68 indeterminate cases were excluded from the primary analysis. All nasopharyngeal swabs were referred to a reference laboratory for polymerase chain reaction testing and identification of EV-D68 through targeting the 5'NTR region and confirmed by amplifying the VP1 gene for serotype determination. Results: Of the 48 children tested there were 9 positive, 36 negative, and 3 indeterminate for EV-D68. Six of the 9 identified cases of EV-D68 were identified in the first week of testing (September 11–18, 2014). There were 35 children (78%) admitted to hospital for ≥1 day. EV-D68 infected children were significantly older (5.2 versus 2.5 years, p = 0.03). They were more likely to be concurrently taking asthma medications (44% versus 11%, p = 0.04) and receiving treatment with salbutamol (100% versus 58%, p = 0.02). There were no cases of severe respiratory distress or acute flaccid paralysis. Three EV-D68 infected children (33%) had viral co-infections identified. Conclusion: This study of a community hospital experience during the fall of 2014 demonstrates a series of mild illnesses from both EV-D68 positive and negative children. EV-D68 isolation was associated with age and asthmatic treatment in children.