Epidemiology and Infection

Gastroenteritis

Norovirus disease associated with excess mortality and use of statins: a retrospective cohort study of an outbreak following a pilgrimage to Lourdes

M. RONDYa1a2 c1, M. KOOPMANSa3a4, C. ROTSAERTa5, T. VAN LOONa5, B. BELJAARSa6, G. VAN DIJKa6, J. SIEBENGAa3a4, S. SVRAKAa3a4, J. W. A. ROSSENa7, P. TEUNISa1a8, W. VAN PELTa1 and L. VERHOEFa3

a1 National Institute for Public Health and the Environment (RIVM), Center for Infectious Diseases Control, Epidemiology and Surveillance Unit, Bilthoven, The Netherlands

a2 European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden

a3 National Institute for Public Health and the Environment (RIVM), Center for Infectious Disease Control, Laboratory for Infectious Diseases and Perinatal Screening, Bilthoven, The Netherlands

a4 Department of Virology, Erasmus Medical Center, Rotterdam, The Netherlands

a5 GGz Regio Breda, Etten-Leur, The Netherlands

a6 Municipal Health Service (GGD), ‘West-Brabant’, Breda, The Netherlands

a7 Laboratory of Medical Microbiology and Immunology, St Elisabeth Hospital, Tilburg, The Netherlands

a8 Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA

SUMMARY

Although norovirus infection is generally known to be a mild disease, there is some evidence for severe outcome. An outbreak in a Dutch psychiatric institution, originating from pilgrims returning from Lourdes (France), provided an opportunity for performing a retrospective cohort study in order to identify risk factors for norovirus disease and excess mortality. Relative risks (RR) including 95% confidence intervals (CI) showed that attending the pilgrimage (RR 2·0, 95% CI 1·4–3·0) and age >70 (RR 1·7, 95% CI 1·2–2·2) were risk factors for symptomatic infection. In a subset of patients, for whom more detailed information was available, the use of statins was associated with norovirus disease when adjusted for underlying condition (adjusted odds ratio 3·9, 95% CI 1·2–13·0). Mortality was higher in cases infected during the pilgrimage compared to other residents (RR 20·9, 95% CI 4·7–93·8). Norovirus disease can lead to severe outcome. The newly identified risk of statins for contracting norovirus disease may have considerable consequences for the Western world and needs prospective confirmation.

(Accepted April 07 2010)

(Online publication May 24 2010)

Correspondence:

c1 Author for correspondence: M. Rondy, National Institute for Public Health and the Environment (RIVM), Postbak 75, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands. (Email: marc.rondy@rivm.nl)

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