Epidemiology and Infection

Respiratory infection

Transmission and control in an institutional pandemic influenza A(H1N1) 2009 outbreak

N. ARINAMINPATHYa1, N. RAPHAELYa2, L. SALDANAa2, C. HODGEKISSa2, J. DANDRIDGEa3, K. KNOXa4 and N. D. McCARTHYa2a5 c1

a1 Department of Ecology and Evolutionary Biology, Princeton University, Princeton, USA

a2 Thames Valley Health Protection Unit, Health Protection Agency, UK

a3 NHS Oxfordshire, Oxford, UK

a4 Summertown Medical Centre, Oxford, UK

a5 Department of Zoology, University of Oxford, Oxford, UK

SUMMARY

A pandemic influenza A(H1N1) 2009 outbreak in a summer school affected 117/276 (42%) students. Residential social contact was associated with risk of infection, and there was no evidence for transmission associated with the classroom setting. Although the summer school had new admissions each week, which provided susceptible students the outbreak was controlled using routine infection control measures (isolation of cases, basic hygiene measures and avoidance of particularly high-risk social events) and prompt treatment of cases. This was in the absence of chemoprophylaxis or vaccination and without altering the basic educational activities of the school. Modelling of the outbreak allowed estimation of the impact of interventions on transmission. These models and follow-up surveillance supported the effectiveness of routine infection control measures to stop the spread of influenza even in this high-risk setting for transmission.

(Accepted July 18 2011)

(Online publication August 23 2011)

Correspondence:

c1 Author for correspondence: Dr N. D. McCarthy, Thames Valley Health Protection Unit, Centre for Radiation, Chemical & Environmental Hazards, Health Protection Agency, Chilton, Didcot OX11 0RQ, UK. (Email: noel.mccarthy@zoo.ox.ac.uk)

Footnotes

† These authors contributed equally to this work.

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