System dynamic modelling of healthcare associated influenza -a tool for infection control

Background The transmission dynamics of influenza virus within healthcare settings are not fully understood.

Capturing the interplay between host, viral and environmental factors is difficult using conventional research methods.

Instead, system dynamic modelling may be used to illustrate the complex scenarios including non-linear relationships and multiple interactions which occur within hospitals during a seasonal influenza epidemic.

We developed such a model intended as a support for health-care providers in identifying potentially effective control strategies to prevent influenza transmission.

Methods By using computer simulation software, we constructed a system dynamic model to illustrate transmission dynamics within a large acute-care hospital.

We used local real-world clinical and epidemiological data collected during the season 2016/17, as well as data from the national surveillance programs and relevant publications to form the basic structure of the model.

Multiple stepwise simulations were performed to identify the relative effectiveness of various control strategies and to produce estimates of the accumulated number of healthcare-associated influenza cases per season.

Results Scenarios regarding the number of patients exposed for influenza virus by shared room and the extent of antiviral prophylaxis and treatment were investigated in relation to estimations of influenza vaccine coverage, vaccine effectiveness and inflow of patients with influenza.

In total, 680 simulations were performed, of which each one resulted in an estimated number per season.

The most effective preventive measure identified by our model was administration of antiviral prophylaxis to exposed patients followed by reducing the number of patients receiving care in shared rooms.

Conclusions This study presents an system dynamic model that can be used to capture the complex dynamics of in-hospital transmission of viral infections and identify potentially effective interventions to prevent healthcare-associated influenza infections.

Our simulations identified antiviral prophylaxis as the most effective way to control in-hospital influenza transmission.