Respiratory Virus Surveillance in Infants across Different Clinical Settings

Abstract

We aimed to evaluate the distribution, clinical presentations and severity of common acute respiratory infections (ARI) viruses in infants across 3 clinical settings. In a prospective virus surveillance study, infants under 1year with fever and/or respiratory symptoms were enrolled from outpatient, emergency department, and inpatient settings from December 16, 2019 through April 30, 2020. Demographic and clinical characteristics were collected through parent/guardian interviews, medical chart abstractions, and follow-up surveys. Nasal swabs were collected and tested for viruses using quantitative reverse-transcription polymerase chain reaction. We enrolled 366 infants and tested nasal swabs on 360 (98%); median age was 6.3months, 50% male. In total, 295 (82%) had at least 1 virus detected; rhinovirus/enterovirus (RV/EV; 42%), respiratory syncytial virus (RSV; 34%), and influenza (15%) were the most common. RSV was the most frequently detected virus in the inpatient (63%) and emergency department (37%) settings, and RV/EV was most frequently detected virus in the outpatient setting (54%). RSV-positive infants had a lower median age (4.9months) and were more likely to have respiratory distress, and RV/EV-positive infants were less likely to have respiratory distress. Influenza-positive infants had a higher median age (8months) and were more likely to have systemic symptoms. RSV infection and younger age were associated with higher odds of hospitalization in multivariable logistic regression. Across 3 clinical settings, and combining virologic, patient, and health-system information, our results highlight the burden of viral ARI among infants. Overall, RSV, RV/EV, and influenza were most commonly detected, with RSV having the highest disease severity.