Martina Sansone1, Maria Andersson1,2, Lars Gustavsson2,3, Lars-Magnus Andersson2,3, Rickard Nordén1,2, Johan Westin1,2,3. 1. Department of Clinical Microbiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden. 2. Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. 3. Department of Infectious Diseases, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden.
Abstract
BACKGROUND: Nosocomial transmission of influenza A virus (InfA) infection is not fully recognized. The aim of this study was to describe the characteristics of hospitalized patients with InfA infections during an entire season and to investigate in-ward transmission at a large, acute-care hospital. METHODS: During the 2016-17 season, all hospitalized patients ≥18 years old with laboratory-verified (real-time polymerase chain reaction) InfA were identified. Cases were characterized according to age; sex; comorbidity; antiviral therapy; viral load, expressed as cycle threshold values; length of hospital stay; 30-day mortality; and whether the InfA infection met criteria for a health care-associated influenza A infection (HCAI). Respiratory samples positive for InfA that were collected at the same wards within 7 days were chosen for whole-genome sequencing (WGS) and a phylogenetic analysis was performed to detect clustering. For reference, concurrent InfA strains from patients with community-acquired infection were included. RESULTS: We identified a total of 435 InfA cases, of which 114 (26%) met the HCAI criteria. The overall 30-day mortality rate was higher among patients with HCAI (9.6% vs 4.6% among non-HCAI patients), although the difference was not statistically significant in a multivariable analysis, where age was the only independent risk factor for death (P < .05). We identified 8 closely related clusters (involving ≥3 cases) and another 10 pairs of strains, supporting in-ward transmission. CONCLUSIONS: We found that the in-ward transmission of InfA occurs frequently and that HCAI may have severe outcomes. WGS may be used for outbreak investigations, as well as for evaluations of the effects of preventive measures.
BACKGROUND: Nosocomial transmission of influenza A virus (InfA) infection is not fully recognized. The aim of this study was to describe the characteristics of hospitalized patients with InfA infections during an entire season and to investigate in-ward transmission at a large, acute-care hospital. METHODS: During the 2016-17 season, all hospitalized patients ≥18 years old with laboratory-verified (real-time polymerase chain reaction) InfA were identified. Cases were characterized according to age; sex; comorbidity; antiviral therapy; viral load, expressed as cycle threshold values; length of hospital stay; 30-day mortality; and whether the InfA infection met criteria for a health care-associated influenza A infection (HCAI). Respiratory samples positive for InfA that were collected at the same wards within 7 days were chosen for whole-genome sequencing (WGS) and a phylogenetic analysis was performed to detect clustering. For reference, concurrent InfA strains from patients with community-acquired infection were included. RESULTS: We identified a total of 435 InfA cases, of which 114 (26%) met the HCAI criteria. The overall 30-day mortality rate was higher among patients with HCAI (9.6% vs 4.6% among non-HCAI patients), although the difference was not statistically significant in a multivariable analysis, where age was the only independent risk factor for death (P < .05). We identified 8 closely related clusters (involving ≥3 cases) and another 10 pairs of strains, supporting in-ward transmission. CONCLUSIONS: We found that the in-ward transmission of InfA occurs frequently and that HCAI may have severe outcomes. WGS may be used for outbreak investigations, as well as for evaluations of the effects of preventive measures.
Authors: Martina Sansone; Paul Holmstrom; Stefan Hallberg; Rickard Nordén; Lars-Magnus Andersson; Johan Westin Journal: BMC Health Serv Res Date: 2022-05-27 Impact factor: 2.908
Authors: Wenrui Li; Katia Bulekova; Brian Gregor; Laura F White; Eric D Kolaczyk Journal: Philos Trans A Math Phys Eng Sci Date: 2022-08-15 Impact factor: 4.019
Authors: Torsten Seemann; Courtney R Lane; Norelle L Sherry; Sebastian Duchene; Anders Gonçalves da Silva; Leon Caly; Michelle Sait; Susan A Ballard; Kristy Horan; Mark B Schultz; Tuyet Hoang; Marion Easton; Sally Dougall; Timothy P Stinear; Julian Druce; Mike Catton; Brett Sutton; Annaliese van Diemen; Charles Alpren; Deborah A Williamson; Benjamin P Howden Journal: Nat Commun Date: 2020-09-01 Impact factor: 14.919