Miss Nikita Parkash1, Ms Wendy Beckingham2, Dr Patiyan Andersson3, Professor Paul Kelly4,5, Associate Professor Sanjaya Senanayake1,4, Dr Nicholas Coatsworth1,4
1Department of Infectious Diseases, Canberra Hospital, Canberra, Australia
2Infection Prevention and Control, Canberra Hospital Health Services, Canberra, Australia
3National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia
4Australian National University Medical School, Canberra, Australia
5Population Health and Prevention Division, ACT Health, Canberra, Australia
Introduction: In 2017 Australia experienced its highest levels of influenza virus activity since the 2009 pandemic. A high proportion of hospital-acquired cases allowed detailed comparison of the characteristics of patients with community and hospital-acquired influenza, and infection control factors that contributed to influenza spread.
Methods: A retrospective observational study was conducted on hospitalised patients with laboratory confirmed influenza at the Canberra Hospital during April-October 2017. Differences between the hospital-acquired and community-acquired cases were assessed by univariate and multivariate analysis. Epidemiologic curves were developed and cluster distribution within the hospital was determined.
Results: A total of 292 patients were included in the study. 28 (9.6%) acquired influenza in hospital, representing a higher proportion than any of the previous 5 years (range 0.9–5.8%). These patients were more likely to have influenza A (P=0.021), had higher rates of diabetes (P=0.015), malignancy (P=0.046) and chronic liver disease (P=0.043). Cases occurred in two distinct clusters. Patients were moved an average of five times after diagnosis. Mean length of stay following diagnosis was 13 days compared to 5 days for community-acquired cases (P<0.001). Of the patients with hospital-acquired influenza, 22 were in shared rooms during their incubation period and 9 were not isolated in single rooms following diagnosis.
Conclusion: Our results show that clinical presentation differed between patients with hospital-acquired influenza compared with those who acquired influenza in the community. Cases occurred in two clusters suggesting intra-hospital transmission rather than random importation from the community, highlighting the importance of infection control measures to limit influenza spread.
Nikita is currently completing her medical degree at the University of New South Wales, and received a scholarship from ACT Health to undertake research at The Canberra Hospital.