Pandemic Flu

Aaron Adams, D.O.

Health Commissioner Scioto County Health Department

Understanding pandemic

► Epidemic: serious outbreak in a single community, population or region ► Pandemic: epidemic spreading around the world affecting hundreds of thousands of people, across many countries

What is a flu pandemic?

► Flu pandemics are global epidemics of a newly emerged strain of flu (a new influenza A subtype) ► Three pandemics in the last century ► Worst killed 20 - 40 million worldwide – more lives lost than during the First World War

What causes pandemic flu?

► Emergence of a new flu virus ► New virus passes easily from person to person ► Few, if any, people have any immunity ► This allows it to spread widely, easily and to cause more serious illness

Who is at risk?

► Everyone is at risk ► Certain groups may be at greater risk of serious illness than others ► Until the virus starts circulating we will not know for sure who is at most risk

Is there a vaccine?

► Because the virus will be new, there will be no vaccine ready to protect against pandemic flu ► A specific vaccine cannot be made until the virus has been identified ► Cannot be predicted in same way as ‘ordinary’ seasonal flu ► ‘Ordinary’ flu vaccine or past flu jab will not provide protection

What is influenza?

► An acute illness resulting from infection by an influenza virus ► Highly infectious ► Can spread rapidly from person to person ► Some strains cause more severe illness than others

Influenza pandemics in last century

Year

1918-19 1957-58 1968-69

Strain

H1N1 H2N2 H3N2

Name

“Spanish” Flu “Asian” Flu “Hong Kong” Flu

Number of confirmed human deaths (UK) Global deaths

250,000 33,000 30,000 20-40 million 1 million 1 million

Lessons from past pandemics

► Occurs unpredictably, not always in winter ► Great variations in mortality, severity of illness and pattern of illness or age most severely affected ► Rapid surge in number of cases over brief period of time, often measured in weeks ► Tend to occur in waves - subsequent waves may be more or less severe Key lesson – unpredictability

Avian influenza

► Highly pathogenic avian flu (A/H5N1) currently circulating in poultry in Asia ► Strain of Avian flu has shown ability to transmit from poultry to people ► Fear that humans infected with Avian flu could also be infected with ‘ordinary’ flu ► Exchange of genes could lead to emergence of a potentially pandemic strain

Avian influenza

Alternatively ► Avian flu strain could evolve into a potentially pandemic strain with greater affinity for people and acquire ability to pass easily from person to person

Year

Cases of Avian influenza in people

Strain Country Number of confirmed human cases Number of confirmed human deaths 1997 1999 2003 2003 2003 2003 2003-2005 A/H5N1 A/H9N2 A/H5N1 A/H7N3 A/H7N7 A/H9N2 A/H5N1 Hong Kong Hong Kong Hong Kong Canada Netherlands Hong Kong Viet Nam, Cambodia, Indonesia and Thailand 18 2 2 2 84 1 116 6 0 1 0 1 0 60 Data up to end September 2005

Cumulative Number of Confirmed Human Cases of Avian Influenza A/(H5N1) Reported to WHO

Country Azerbaijan 0 cases 2003 deaths 0 0 cases 2004 deaths 0 0 cases 2005 deaths 0 8 cases 2006 deaths 5 8 cases Total deaths 5 Cambodia China Djibouti Egypt Indonesia Iraq Thailand Turkey Viet Nam Total 0 0 0 0 0 0 0 3 3 0 0 0 0 0 0 0 3 3 0 0 Total number of cases includes number of deaths.

WHO reports only laboratory-confirmed cases.

0 0 0 17 0 29 46 0 0 0 0 0 12 0 20 32 4 8 0 17 0 5 0 61 95 4 5 0 11 0 2 0 19 41 2 10 1 13 16 2 0 12 0 64 2 7 0 5 14 2 0 4 0 39 6 18 1 13 33 2 22 12 93 208 115

May 12 th ,2006

6 12 0 5 25 2 14 4 42

Nations with confirmed cases of H5N1 Avian Influenza

May 12th , 2006

Bird Migration

Migratory water birds

Avian influenza from birds to humans

Domestic birds

•

Hong Kong 1997, H5N1

•

HK, China 1999, H9N2

•

Netherlands 2003, H7N7

•

Hong Kong 2003, H5N1

•

Viet Nam and Thailand, 2004 H5N1

The world has changed

► Global population in 18th century was <1 billion vs. 6 billion today ► Intercontinental travel is in hours rather than months and in millions rather than hundreds ► Human crowding has increased ► Population health has improved ► Animal husbandry has changed ► Interdependence has increased

Opportunities for virus emergence and spread

► Modern pig and poultry production create conditions for mass animal influenza outbreaks ► Proximity of humans and animals in many markets create potential for virus recombination ► Human crowding and travel present opportunities for virus spread

Pandemic flu effect

► Impossible to predict when it will begin ► Difficult to predict impact with any accuracy ► Estimates of scale of illness, death rates and those most likely to have severe illness are uncertain ► Will also depend on the availability and effectiveness of antiviral drugs and vaccines

Impact on health services

► Likely to place great pressure on health and social services   Increased numbers of patients requiring treatment Depletion of the workforce due to illness and other disruption

Impact on business

► 25% of the US workforce will take 5-8 working days off over a three-month period ► Estimates suggest that during the peak absenteeism will double in the private sector and increase by two-thirds in the public sector

Impact on schools and services

► Likely to spread rapidly in schools and other closed communities ► Impact on all services including police, fire, the military, fuel supply, food production, distribution and transport, prisons, education and business

Reduce impact through:

► Surveillance ► Diagnosis ► Antiviral drugs ► Vaccines (once they become available) ► Public health interventions

SERENITY PRAYER

God grant me the serenity to accept the things I cannot change, the courage to change the things I can and the wisdom to know the difference.

Reinhold Niebuhr, 1932