Controlling nosocomial infection based on structure of hospital social networks Taro Ueno1,2, Naoki Masuda3,4 1 Institute of Molecular Embryology and Genetics, The University of Kumamoto 2 Tokyo Metropolitan Hiroo General Hospital 3 Graduate School of Information Science and Technology, The University of Tokyo 4 JST Presto Ref: J. Theor. Biol., 254, 655-666 (2008).
Objective of this study•Control nosocomial infections •By changing structure of hospital social networks •By vaccinating some individuals beforehand•What is special about that? •Hierarchical network structure •Hospital speciﬁc antibiotics-resistant pathogens (e.g. MRSA, VRE). •Severe results in immuno-deﬁcient patients •As initiator or booster of epidemic outbreaks at urban community and world-wide levels
Social networks of a hospital• Data from a community hospital in Tokyo, Japan• Nodes [頂点] • (Hospitalized) Patient (Pt) [入院患者] • Nurse (Ns) [看護師] • (Medical) doctors (Dr) [医師]• Links [枝] • Pt-Ns, Pt-Dr, Ns-Dr, Dr-Dr ← medical record [カルテ] • (Dr-Dr ← same team) • Pt-Pt ← same room [同じ病室] • Ns-Ns ← same ward [同じ病棟]
Def of contact networkmedical record network medical doctor [医師] nurse [看護師] hospitalized patients [入院患者]
Hierarchical Structure [ネットワークの階層構造] team department [診療科]room [病室]ward [病棟] Dr [医師] Ns [看護師] Pt [入院患者]
vaccination• Constraint: only 20 out of 605 can be vaccinated beforehand (by assuming R state in the SIR dynamics at time 0).• Strategies for selecting vaccinated individuals • Random [無作為] • Degree based [次数] • Betweenness centrality based [媒介中心性] • High-betweenness individuals are mostly Drs. Some Ns also included. • Recalculated betweenness centrality based
Conclusions• The observed hospital social network is small-world and hierarchical.• Healthcare workers (particularly Dr) are main transmitters. [医師が感染を媒介する]• Intervention: Restricting interaction between Drs and their visits to diﬀerent wards is more eﬀective than isolating Pts in single rooms. [チーム解消, 患者入れ替え > 病室個室化]• Vaccination: betweenness-based > degree-based. [媒介中心 性でワクチン接種するとよい] • Mostly doctors, some nurses • But the eﬀectiveness of betweenness-based vaccination may not be general for networks with hierarchical or community structure.