Clinical phenotypes and outcomes of SARS-CoV-2, influenza, RSV and seven other respiratory viruses: a retrospective study using complete hospital data

Abstract

Background: An understanding of differences in clinical phenotypes and outcomes COVID-19 compared with other respiratory viral infections is important to optimise the management of patients and plan healthcare. Herein we sought to investigate such differences in patients positive for SARS-CoV-2 compared with influenza, respiratory syncytial virus (RSV) and other respiratory viruses.

Methods: We performed a retrospective cohort study of hospitalised adults and children (≤15 years) who tested positive for SARS-CoV-2, influenza virus A/B, RSV, rhinovirus, enterovirus, parainfluenza viruses, metapneumovirus, seasonal coronaviruses, adenovirus or bocavirus in a respiratory sample at admission between 2011 and 2020.

Results: A total of 6321 adult (1721 SARS-CoV-2) and 6379 paediatric (101 SARS-CoV-2) healthcare episodes were included in the study. In adults, SARS-CoV-2 positivity was independently associated with younger age, male sex, overweight/obesity, diabetes and hypertension, tachypnoea as well as better haemodynamic measurements, white cell count, platelet count and creatinine values. Furthermore, SARS-CoV-2 was associated with higher 30-day mortality as compared with influenza (adjusted HR (aHR) 4.43, 95% CI 3.51 to 5.59), RSV (aHR 3.81, 95% CI 2.72 to 5.34) and other respiratory viruses (aHR 3.46, 95% CI 2.61 to 4.60), as well as higher 90-day mortality, ICU admission, ICU mortality and pulmonary embolism in adults. In children, patients with SARS-CoV-2 were older and had lower prevalence of chronic cardiac and respiratory diseases compared with other viruses.

Conclusions: SARS-CoV-2 is associated with more severe outcomes compared with other respiratory viruses, and although associated with specific patient and clinical characteristics at admission, a substantial overlap precludes discrimination based on these characteristics.

Keywords: COVID-19; pneumonia; respiratory infection; viral infection.

Figure 1

Flow chart of adult and paediatric healthcare episodes in the study. ^aAdmission defined as −24 to +48 hours in relation to the admission time point. ^bRepeated positive for same respiratory virus in respiratory sample within 3 months. ^cEighty-two adult healthcare episodes with PCR unable to discriminate between rhinoviruses and enteroviruses due to cross reactivity in the PCR assay. These cases were included in the other viruses group but excluded from virus group-specific analyses. AdV, adenovirus; BoV, bocavirus; EV, enterovirus; MPV, metapneumoviruses; PIV, parainfluenzaviruses; RSV, respiratory syncytial virus; RV, rhinovirus; sCoV, seasonal coronavirus.

Figure 2

Unadjusted Kaplan-Meier curves (A) and standardised survival function curves (B) for mortality by virus group. (A) Unadjusted Kaplan-Meier curves and risk tables for 30-day (left) and 90-day (right) mortality. P value represents result of significance testing using log-rank tests. The 30-day mortality Kaplan-Meier curves for the influenza and other viruses groups overlap. (B) Complete case-based standardised survival functions for 30-day (left) and 90-day (right) mortality. For 30-day mortality, complete data were available for 1272 SARS-CoV-2, 2220 influenza, 591 RSV and 1386 other viruses healthcare episodes. For 90-day mortality, complete data were available for 1194 SARS-CoV-2, 2118 influenza, 555 RSV and 1315 other viruses healthcare episodes. The survival functions were all standardised and adjusted for sex, age, BMI category, diabetes, hypertension, cardiac disease, respiratory disease, chronic kidney disease and malignancy as presented in table 1. The 30-day mortality curves for the influenza, RSV and other viruses groups overlap. AdV, adenovirus; BMI, body mass index; BoV, bocavirus; EV, enterovirus; MPV, metapneumoviruses; PIV, parainfluenzaviruses; RSV, respiratory syncytial virus; RV, rhinovirus; sCoV, seasonal coronavirus.