Interactions between SARS-CoV-2 and influenza, and the impact of coinfection on disease severity: a test-negative design

Abstract Background The impact of SARS-CoV-2 alongside influenza is a major concern in the northern hemisphere as winter approaches. Methods Test data for and from national surveillance systems between 20 January 2020 25 April were used to estimate infection on risk infection. A test-negative design was assess odds those who tested positive compared with negative. severity also assessed using univariable multivariable analyses. Results testing 58% lower among influenza-positive cases patients coinfection had death 5.92 (95% confidence interval: 3.21–10.91) times greater than neither nor SARS-CoV-2. ventilator use or intensive care unit admission greatest coinfected patients. Conclusions Coinfection these viruses could have significant morbidity, mortality health-service demand.