The association between influenza infections in primary care and intensive care admissions for severe acute respiratory infection (SARI): A modelling approach. Issue 5 (12th June 2020)

• Record Type: Journal Article
• Authors: van Asten, Liselotte; Luna Pinzon, Angie; van de Kassteele, Jan; Donker, Gé; de Lange, Dylan W.; Dongelmans, Dave A.; de Keizer, Nicolette F.; van der Hoek, Wim
• Is Part Of: Influenza and other respiratory viruses. Volume 14:Issue 5(2020)
• Page Start: 575
• Page End: 586
• Publication Date: 2020-06-12
• Subjects: association -- ILI -- influenza -- intensive care -- pneumonia -- regression model -- SARI -- seasonality -- Surveillance -- time series -- trends; Influenza -- Periodicals; Respiratory infections -- Periodicals; Virus diseases -- Periodicals; Influenza, Human -- Periodicals; Respiratory Tract Diseases -- Periodicals; Virus Diseases -- Periodicals; Grippe -- Périodiques; Appareil respiratoire -- Infections -- Périodiques; Maladies à virus -- Périodiques; 616.203
• DOI: 10.1111/irv.12759
• Languages: English
• ISSNs: 1750-2640

Abstract

Abstract: Background: The burden of severe influenza virus infections is poorly known, for which surveillance of severe acute respiratory infection (SARI) is encouraged. Hospitalized SARI patients are however not always tested for influenza virus infection. Thus, to estimate the impact of influenza circulation we studied how influenza in primary care relates to intensive care unit (ICU) admissions using a modelling approach. Methods: We used time‐series regression modelling to estimate a) the number of SARI admissions to ICU associated with medically attended influenza infections in primary care; b) how this varies by season; and c) the time lag between SARI and influenza time series. We analysed weekly adult ICU admissions (registry data) and adult influenza incidence (primary care surveillance data) from July 2007 through June 2016. Results: Depending on the year, 0% to 12% of annual SARI admissions were associated with influenza (0‐554 in absolute numbers; population rate: 0/10 000‐0.39/10 000 inhabitants), up to 27% during influenza epidemics. The average optimal fitting lag was +1 week (SARI trend preceding influenza by 1 week), varying between seasons (−1 to +4) with most seasons showing positive lags. Conclusion: Up to 12% of yearly SARI admissions to adult ICU are associated with influenza, but with large year‐to‐year variation and higher during influenza epidemics. In most years, SARI increases earlier than medically attended influenza infections in the general population. SARI surveillance could thus complement influenza‐like illness surveillance by providing an indication of the season‐specific burden of severe influenza infections and potential early warning of influenza activity and severity.