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Pandemic Influenza: Surge Capacity and Prioritisation in Health Services

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Appendix 1: World Health Organization international phases and UK alert levels

Phase

WHO international phases

Overarching public health goals

Inter-pandemic period

1

No new influenza virus subtypes detected in humans

Strengthen influenza pandemic preparedness at global, regional, national and sub-national levels

Minimise the risk of transmission to humans; detect and report such transmission rapidly if it occurs

2

Animal influenza virus subtype poses substantial risk

Pandemic alert period

3

Human infection(s) with a new subtype, but no (or rare) person-to-person spread to a close contact

Ensure rapid characterisation of the new virus subtype and early detection, notification and response to additional cases

Contain new virus or delay its spread to gain time to implement preparedness measures, including vaccine development

Maximise efforts to contain or delay spread, to possibly avert a pandemic and to gain time to implement response measures

4

Small cluster(s) with limited person-to-person transmission but spread is highly localised, suggesting that the virus is becoming increasingly better adapted to humans

5

Large cluster(s) but person-to-person spread still localised, suggesting that the virus is becoming increasingly better adapted to humans

Pandemic period

6

Increased and sustained transmission in general population

UK alert levels

1 Virus/cases only outside the UK

2 Virus isolated in the UK

3 Outbreak(s) in the UK

4 Widespread activity across the UK

Minimise the impact of the pandemic

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Page updated: Tuesday, October 28, 2008