323. Keys to Control Influenza Outbreaks in Long-term Care Facilities
Session: Poster Abstract Session: HAI: Long Term Care
Thursday, October 8, 2015
Room: Poster Hall
  • IDWeek2015 POSTER 323.pdf (300.9 kB)
  • Background: In Japan, the 2014 influenza season began earlier than usual. The dominant virus strain was H3N2 and multiple outbreaks with fatal cases occurred in long-term care facilities (LTCFs) nationwide. We conducted an influenza outbreak investigation at a hospital attached LTCF in western part of Japan.

    Methods: A total of 675 persons were investigated including health-care workers (HCWs), inpatients and residents in the LTCF. Their demographic information, symptoms, vaccination and prophylaxis status were collected from charts and questionnaires. Confirmed cases were defined as people tested positive for the influenza virus by a rapid test kit from 19 December 2014 to 19 January 2015. We interviewed the stakeholders to ascertain undertaken preventive measures. Hospital and LTCF rounds were conducted to observe infection prevention procedures. Vaccine effectiveness (VE) was calculated using following formula: 100 x (1 - relative risk). Nasopharyngeal specimens were collected from cases to conduct genetic analyses.

    Results: Confirmed cases were 11% (36/338), 16% (42/264), and 27% (20/73) for HCWs, inpatient, and residents in LTCF. All cases were influenza A and an isolated strain was H3N2. Median age for each group was 40, 84.5, and 91 years respectively. No influenza related complications occurred among residents even though 70% of cases had high risks. The vaccine coverage rate was available for HCWs and LTCF residents; 85% and 97%. VE was estimated only for HCWs and it was 28%, adjusted for sex, age, and occupation. The majority was given prophylaxis, but given towards the end of the outbreak. Interview revealed that index case was not recognized by most of HCWs initially, which delayed introduction of preventive measures. However, rehabilitation care group had no case during study period. One staff noticed the index case early and shared it with the rest of the group, allowing them to introduce various preventive measures swiftly.

    Conclusion: Our results indicated that there is no single effective preventive measure to prevent influenza transmission in LTCFs. Multiple preventive measures such as standard, contact, and droplet precautions and high vaccine coverage in conjunction with prophylaxis with early detection of cases are required.

    Kunio Kawabata, DDS, PhD1, Masahiro Ishikane, MD1, Takuya Yamagishi, MD, PhD1, Norio Ohmagari, MD, MSc, PhD2, Yuko Sugiki, RN2, Takato Odagiri, PhD1, Tamano Matsui, MD, PhD1, Kazunori Oishi, MD, PhD1 and Hajime Kamiya, MD, MPH, PhD1, (1)National Institute of Infectious Diseases, Tokyo, Japan, (2)National Center for Global Health and Medicine Hospital, Tokyo, Japan


    K. Kawabata, None

    M. Ishikane, None

    T. Yamagishi, None

    N. Ohmagari, None

    Y. Sugiki, None

    T. Odagiri, None

    T. Matsui, None

    K. Oishi, None

    H. Kamiya, None

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