Flu Through the AgesDr Katy Kidd

Retired Medical Director and Director of Infection Prevention and Control at Wirral PCT

Definition: Greek "All the people"

A new or long dormant infection

Spreads easily from person to person

Spreads to many countries/continents

Normally causes serious illness and death

There is a formal WHO definition which has varied at times, this includes 6 phases in the development of an influenza pandemic

Planning is based on these phases

Pandemics

1918 "Spanish Flu“ H1N1, 20 to 50 million dead, affected all age groups

1957 " Asian Flu" H2N2, 1.5 million dead, first wave affected children particularly, second wave elderly

1968 " Hong Kong Flu" H3N2, 1 million dead, mainly elderly affected

2009 " Swine Flu" H1N1, 284,500 dead, mainly affected pregnant women, those with pre-existing conditions

Influenza Pandemics of the Last Century

Virus in birds ( avian flu)...mutated...in humans...spread to pigs

“Parent” virus to subsequent pandemics

Affected 40% of world population

Onset of symptoms very fast

3 waves◦ Spring/summer 1918◦ Autumn 1918◦ Spring 1919

Rapid international spread encouraged by wartime/post war troop movements

Killed more people than First World War

1918 Spanish Flu

Genetic reassortment between the existing H1N1 virus and an avian H2N2 influenza virus

Started in China in February 1957, within six months, the pandemic spanned the entire globe

Cases were concentrated in school aged children and those crowded together

In the UK the impact on mortality was in the elderly

Appeared to be over end of 1957, 2nd wave in early 1958 which caused high rates of illness and increased fatalities

The 2 waves together affected some 40-50% of people

1957 Asian Flu

Resulted from genetic reassortment and arose in Southeast Asia, started in China July 1968, spread to Hong Kong same month, spreading rapidly across the whole world

Half a million cases were reported in Hong Kong in just two weeks

Identified as a novel influenza A subtype, H3N2, in August 1968

Reached the US in September 1968, via US Marines returning from service in Vietnam

Vaccine manufacture began within two months of the virus being isolated

1-3 million fatalities, of which over 30,000 were from the UK

1968 Hong Kong Flu

Antibiotics ◦Mid 1940s (military) ◦Late 1940s (General)

Vaccines

◦Early 1940s (early versions, US military) ◦1960s (general, including UK)

Antivirals

◦1999 specific flu antivirals (oseltamivir and zanamivir)

Influenza Prophylaxis and Treatment

Expected, as longest previous interval between pandemics was 39 years

Led by WHO, many countries started planning in 2005

Avian Flu expected, probably arising in Far East

UK took risk very seriously, on a par with terrorist attacks Detailed central and local planning in UK, escalating in 2007

Only treatment available for first wave of flu to be targeted antivirals, as vaccine expected to take 6 months

Planning for Influenza Pandemic

April 2009 Cases of swine flu in humans in Mexico, identified as H1N1, early cases suggest high mortality

Rapid spread to other countries and continents

June 2009 - WHO declares Influenza Pandemic

Vaccine available in 4 months

By November 2009 cases declining internationally

Morbidity and mortality much lower than anticipated, although pregnant women particularly affected

August 2010 - WHO declares pandemic over

Winter 2010/11 H1N1 now part of seasonal flu strains. Problematic locally, especially over Xmas 2010

2009 Swine Flu Pandemic

Virus emerged in humans following multiple reassortment events between swine viruses

Emerged in Mexico in mid February

Mid April the new virus was identified in California as an H1N1 virus of swine origin

By 21 May, 41 countries had reported 11,034 cases including 85 deaths

UK first imported cases were detected on 27 April and a wave of activity gradually took off peaking in mid/late July

2009 Swine Flu

Rates of infection were highest in children & young adults and lowest among the elderly

Elderly may have had some cross protective immunity from exposure in the 1950s to related influenza viruses

The pandemic vaccine was not available until October 2009

Globally 284,500 deaths

H1N1 virus remains one of the seasonal flu strains

2009 Swine Flu

Pandemic (H1N1) Influenza - 2009

Wirral PCT coordinated the response to Swine Flu

Anti-viral Collection Points (AVCP) established across Wirral

Staffed by Wirral PCT

Infection control training provided to staff working in AVCP

Infection control support to all Providers across Wirral

Late October 2009 – vaccine available for priority groups

Phase 2 of vaccine programme – December 2009 (children 6 months – 5 years)

2009 Swine Flu

Majority of hospitalisations and deaths were in people aged less than 65 years

Highest hospitalisation rate was consistently in children aged less than 5 years

2,831 people hospitalised in England

First reported UK death occurred on 14 June 2009

474 UK deaths were reported up to 15 April 2010◦ 359 in England◦ 69 in Scotland◦ 18 in Northern Ireland◦ 28 in Wales

2009 Swine Flu

Quiz

What can you remember about:◦Glenfield Hospital, Leicester ?◦Respirator fit testing ?◦Chinese star anise ?◦Rosie the Riveter ?

Wirral Community NHS Trust staff – flu vaccine available for all – see staffzone for further details

Staff working in Health & Social Care – discuss availability of vaccine with employer

In a clinical risk group – see your GP

Be a Flu Fighter!