Using contact network dynamics to implement efficient interventions against pathogen spread in hospital settings
Authors: Leclerc Quentin , Duval Audrey , Guillemot Didier , Opatowski Lulla , Temime Laura 
Published: December 2023

AbstractLong-term care facilities (LTCF) are hotspots for pathogen transmission. Infection control interventions are essential, but the high density and heterogeneity of inter-individual contacts within LTCF may hinder their efficacy. Here, we explore how the patient-staff contact structure may inform effective intervention implementation. Using an individual-based model, we reproduced methicillin-resistantStaphylococcus aureuscolonisation dynamics over a detailed contact network recorded within an LTCF, and examined the potential impact of three types of interventions against transmission (reallocation reducing the number of unique contacts per staff, reinforced contact precautions, and vaccination protecting against acquisition), targeted towards specific populations. All three interventions were effective when applied to all nurses or healthcare assistants (median reduction in MRSA colonisation incidence up to 21%), but the benefit did not exceed 8% when targeting any other single staff category. We identified “supercontactor” individuals with most contacts (“frequency-based”, overrepresented amongst nurses, porters and rehabilitation staff) or with the longest cumulative time spent in contact (“duration-based”, overrepresented amongst healthcare assistants and geriatric and persistent-vegetative-state patients). Targeting supercontactors enhanced interventions against pathogen spread in the LTCF. With contact precautions, targeting frequency-based staff supercontactors led to the highest incidence reduction (13%). Vaccinating duration-based patient supercontactors led to a higher reduction (22%) than all other approaches. Targeting supercontactors remained the most effective strategy when varying epidemiological parameters, indicating this approach can be broadly applied to prevent transmission of other nosocomial pathogens. Importantly, both staff and patients may be supercontactors, highlighting the importance of including patients in measures to prevent pathogen transmission in LTCF.Classification:Biological Sciences, Biophysics and Computational BiologySignificance statementPathogen transmission is a challenge in long-term care facilities (LTCF) due to frequent and heterogeneous contacts of staff and patients. By characterising this contact structure and understanding the categories of staff and patients more likely to be “supercontactors”, with either more or longer contacts than others, we can implement more efficient interventions against pathogen spread. We illustrate this using a mathematical model to reproduce transmission of methicillin-resistantStaphylococcus aureusacross a detailed contact network recorded in a LTCF. We show how the most efficient implementation strategy depends on the intervention (reallocation, contact precautions, vaccination) and target population (staff, patients, supercontactors). By varying epidemiological parameters, we demonstrate that these results are broadly applicable to prevent transmission of other nosocomial pathogens.