Outbreaks of influenza-like illness in long-term care facilities in Winnipeg, Canada

Salaheddin M Mahmud, Laura H Thompson, Deborah L Nowicki, Pierre J Plourde, Salaheddin M Mahmud, Laura H Thompson, Deborah L Nowicki, Pierre J Plourde

Abstract

Background: Outbreaks of influenza-like illness (ILI) are common in long-term care facilities (LTCFs) and result in significant morbidity and mortality among residents.

Objectives: We describe patterns of reported ILI outbreaks in LTCFs in Winnipeg, Canada, and examine LTCF and outbreak characteristics that influence the clinical outcomes of these outbreaks.

Methods: We analyzed the electronic records of all ILI outbreaks reported by LTCFs in Winnipeg from 2003 to 2011. Outbreak duration, ILI attack rates among staff and residents, and residents' death rates were calculated by presumed viral etiology, staff vaccination rates, type of influenza chemoprophylaxis used, and time to notification to public health.

Results: Of a total of 154 reported outbreaks, most (N=80) were attributed to influenza, and these outbreaks tended to have higher attack and death rates among LTCF residents compared with outbreaks caused by other respiratory viruses (12) or those of unknown etiology (62). About 92% of residents and 38% of staff of the average LTCFs were vaccinated. Chemoprophylaxis was used in 57·5% of influenza outbreaks. Regardless of presumed viral etiology, outbreaks reported within 3 days of onset ended sooner and had lower attack and mortality rates among residents.

Conclusions: Influenza-like illness outbreaks still occur among highly immunized LTCF residents, so in addition to vaccination of staff and residents, it is important to maintain competent infection control practices. Early identification and notification to public health authorities and possibly early initiation of control measures could improve clinical outcomes of ILI outbreaks.

Keywords: Epidemiology; influenza-like illness outbreaks; long-term care facilities.

© 2012 John Wiley & Sons Ltd.

Figures

Figure 1
Figure 1
Number of reported influenza‐like illness (ILI) outbreaks by etiology and calendar year and quarter.

References

    1. Loeb M, McGeer A, McArthur M, Peeling RW, Petric M, Simor AE. Surveillance for outbreaks of respiratory tract infections in nursing homes. Can Med Assoc J 2000; 162:1133–1137.
    1. Tamblyn S. Recognizing and controlling respiratory disease outbreaks in long‐term care facilities. CMAJ 1997; 157:1257.
    1. Lofgren E, Fefferman N, Naumov Y, Gorski J, Naumova E. Influenza seasonality: underlying causes and modeling theories. J Virol 2007; 81:5429.
    1. Dolin R. Influenza – interpandemic as well as pandemic disease. N Engl J Med 2005; 353:2535–2537.
    1. Vaux S, Poujol I, Bonmarin I, Lévy‐Bruhl D, Desenclos J‐C. Surveillance of lower respiratory tract infections outbreaks in nursing homes in France. Eur J Epidemiol 2009; 24:149–155.
    1. Stevenson CG, McArthur MA, Naus M, Abraham E, McGeer AJ. Prevention of influenza and pneumococcal pneumonia in Canadian long‐term care facilities: how are we doing? Can Med Assoc J 2001; 164:1413–1419.
    1. Manitoba Health . Communicable disease management protocols: seasonal influenza. Winnipeg, Manitoba, 2011. Available at (Ac‐cessed 15 December 2011).
    1. Rosewell A, Chiu C, Lindley R et al. Surveillance for outbreaks of influenza‐like illness in the institutionalized elderly. Epidemiol Infect 2010; 138:1126.
    1. Utsumi M, Makimoto K, Quroshi N, Ashida N. Types of infectious outbreaks and their impact in elderly care facilities: a review of the literature. Age Ageing 2010; 39:299–305.
    1. Guy RJ, Di Natale R, Kelly HA et al. Influenza outbreaks in aged‐care facilities: staff vaccination and the emerging use of antiviral therapy. Med J Aust 2004; 180:640.
    1. Morens DM, Rash VM. Lessons from a nursing home outbreak of influenza A. Infect Control Hosp Epidemiol 1995; 16:275–280.
    1. Durando P, Iudici R, Alicino C et al. Adjuvants and alternative routes of administration towards the development of the ideal influenza vaccine. Hum Vaccin Immunother 2011; 7:29–40.
    1. Skowronski DM, De Serres G, Dickinson J et al. Component‐specific effectiveness of trivalent influenza vaccine as monitored through a sentinel surveillance network in Canada, 2006–2007. J Infect Dis 2009; 199:168–179.
    1. Thomas RE, Jefferson T, Lasserson TJ. Influenza vaccination for healthcare workers who work with the elderly. Cochrane Database Syst Rev 2010; 2:CD005187.
    1. Lemaitre M, Meret T, Rothan‐Tondeur M et al. Effect of influenza vaccination of nursing home staff on mortality of residents: a cluster‐randomized trial. J Am Geriatr Soc 2009; 57:1580–1586.
    1. Cai S, Temkin‐Greener H. Influenza vaccination and its impact on hospitalization events in nursing homes. J Am Med Dir Assoc 2011; 12:493–498.
    1. Monto AS, Rotthoff J, Teich E et al. Detection and control of influenza outbreaks in well‐vaccinated nursing home populations. Clin Infect Dis 2004; 39:459.
    1. Peters PH Jr, Gravenstein S, Norwood P et al. Long‐term use of oseltamivir for the prophylaxis of influenza in a vaccinated frail older population. J Am Geriatr Soc 2001; 49:1025–1031.
    1. Rubin MS, Nivin B, Ackelsberg J. Effect of timing of amantadine chemoprophylaxis on severity of outbreaks of influenza A in adult long‐term care facilities. Clin Infect Dis 2008; 47:47–52.
    1. Smith PW, Bennett G, Bradley S et al. SHEA/APIC Guideline: infection prevention and control in the long‐term care facility. Infect Control Hosp Epidemiol 2008; 29:785–814.

Source: PubMed

Sponsors et collaborateurs

Les conditions médicales

Interventions en matière de drogue

3
S'abonner