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Preparing for an Influenza Pandemic in Westminster. Health and Community Services Overview and Scrutiny Committee 9 Oct 2006 Dr Margaret Guy Director of Public Health. What is a flu pandemic? Flu pandemics occur when a new influenza virus emerges which is able to:. infect people;
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Preparing for an Influenza Pandemic in Westminster Health and Community Services Overview and Scrutiny Committee 9 Oct 2006 Dr Margaret Guy Director of Public Health
What is a flu pandemic?Flu pandemics occur when a new influenza virus emerges which is able to: • infect people; • spread readily from person to person; • cause illness in high proportion of people infected; and • spread widely.
Influenza virus • An RNA virus • Three types: A, B, and C • A & B are major human pathogens: give rise to ‘normal’ epidemics in winter • Only influenza A virus is recognised as having the potential to cause a pandemic
Influenza A subtypes • H antigen - 16 different subtypes • N antigen - 9 different subtypes • Both antigens change over time, H more than N • Drift Minor continuous changes in same subtype Results in epidemics - almost every winter • Shift Major abrupt change in subtype May result in pandemic as little/no immunity
1918: “Spanish Flu” 1957: “Asian Flu” 1968: “Hong Kong Flu” 40-50 million deaths 1 million deaths 1 million deaths Circulating influenza strains in humans and pandemics in 20th Century H3N2 H2N2 H1N1 H1N1 1920 1940 1960 1980 2000
Migratory water birds Domestic birds Transmission of Avian Flu to humans • Hong Kong 1997, H5N1 • Hong Kong and China 1999, H9N2 • Netherlands 2003, H7N7 • Hong Kong 2003, H5N1 • Vietnam and Thailand, 2004 H5N1
Migratory water birds Emergence of pandemic strains
Avian Flu - H5N1 • First isolated from terns in 1961 in S. Africa • Outbreaks in 8 countries in SE Asia during late 2003 and early 2004 • From late June 2004 new deadly outbreaks reported in Cambodia, China, Indonesia, Malaysia Thailand Vietnam and Turkey • These are ongoing
Mortality during the pandemic of 1918-19 A/H1N1 – Spanish influenza • 3 epidemic waves in fairly close succession • March 1918, Sept 1918, Feb 1919 • Up to 40 million deaths world-wide, including… • 198,000 excess civilian deaths in Britain • 500,000 excess civilian deaths in USA
Mortality in other 20th century pandemics 1957-1958 (A/H2N2) – Asian flu • USA, 80,000 excess deaths • Worldwide: Estimated 1.0 million deaths 1968-1970 (A/H3N2) – Hong Kong flu • UK: 30,000 excess deaths (c/f 26,000 in 1989-90) • Worldwide: Estimated 0.8 – 1.0 million deaths
Morbidity associated with pandemic influenza People who consult their GP 1968 25-33% 1918 People infected with symptoms 25% 1957 25-33% 50% People infected without symptoms
WHO Influenza Pandemic Phases • Inter-pandemic Period Phase 1 No new influenza virus subtypes detected in humans. Phase 2 No new influenza virus subtypes detected in humans, but circulating animal influenza virus subtype poses substantial risk of human disease. • Pandemic Alert Period Phase 3 Human infection with new subtype but no new human-to-human spread, or, at most, rare instances of spread to close contact. Phase 4 Small cluster(s) with limited human-to-human transmission but spread highly localised, suggesting virus not well adapted to humans Phase 5 Large cluster(s) but human-to-human spread still localised, suggesting virus becoming increasingly better adapted to humans, but may not yet be fully transmissible (substantial pandemic risk). • Pandemic Period Phase 6 Pandemic phase: increased and sustained transmission in general population; second and further waves likely 3-9 months after previous wave has subsided • Post Pandemic Period Return to inter-pandemic period
Implications for the UK • If there are cases in the UK during the pre-pandemic period, the international phases apply. • Once a pandemic has been declared (Phase 6), a four point UK-specific alert mechanism has been developed (consistent with alert levels used in other UK infectious disease response plans): Alert level 1: Cases outside the UK Alert level 2: New virus isolated in the UK Alert level 3: Outbreak(s) in the UK Alert level 4: Widespread activity across the UK.
Influenza – transmission of infection Incubation period 1-3 days Virus shedding 24 hours before symptoms and up to 9 days after onset of symptoms Only considered to be infective when symptomatic Transmission Respiratory secretions - airborne droplet spread by coughing, sneezing or contaminated hands
Reducing the impact of a Flu Pandemic • Immunisation against influenza • Pneumococcal immunisation • Measures to reduce the transmission of influenza • Restriction of travel or mass gatherings • Action by individuals • Action by health and care staff • Action to reduce spread in residential facilities • Antiviral drugs
Planning for a Flu Pandemic • National UK National Influenza Pandemic Committee (UKNIPC) National Director of Pandemic Influenza Preparedness • London London Health Pandemic Flu Steering Group London Pandemic Flu Coordinator • Westminster Westminster Influenza Pandemic Committee WestminsterInfluenza Pandemic Coordinator
Local estimates of service demand (17-week pandemic wave) *The highest figures are given for week 9 within a 17 week pandemic wave period ** Estimated 25% attack rate with 50% attack rate given in parenthesis
Service demand during worst 8 weeks of pandemic (weeks 5-12) **Estimated 25% attack rate with 50% attack rate given in parenthesis
Workstreams • Westminster-wide work • Joint work between all health service providers • Joint work with Westminster City Council
Westminster-wide work • Overarching Westminster Influenza Pandemic Contingency Plan • Command and control structures • Agreeing responsibility for local actions + development of action cards • Business continuity • Communications Strategy • Staff training • Supplies and logistics • Monitoring arrangements • Budgets
Joint work between health service providers • Arrangements for administering antivirals and vaccine – Flu centres • Supporting self care • Triage of those who seek advice • Mounting the Primary Care Response • Mounting the Secondary Response • Maintaining services for people who do not have influenza • Role of private hospitals and nursing homes • Hospice care provision • Infection control measures • Ensuring business continuity plans are complementary
Joint work with Westminster City Council • Flu centres – identification of suitable sites • Mortuaries – including liaison with Coroner • Joint work with Social Services in relation to the provision of services to people in receipt of PCT services and social services • Ensuring business continuity plans are complementary • Provision of antivirals/vaccine for WCC essential staff