Pandemic Influenza: What Is It and Why Should We Care?

Dr. Judith A. Monroe, MDState Health Commissioner

What is Influenza? Viral respiratory illness that occurs usually during the winter

months

Spread by droplets from coughing or sneezing, then touching eyes, nose or mouth

Symptoms– fever, chills, cough, sore throat, muscle aches– begin about 1-4 days after exposure

May lead to pneumonia or respiratory distress– elderly– young– weakened immune systems

Influenza Viruses

Type A – Infects humans and animals (such as birds and pigs)– Capable of major genetic changes resulting in new virus

subtypes– Most severe illness

Type B– Infects only humans– Less severe illness– Minor genetic changes

What is a Pandemic? Pandemic = worldwide epidemic

Occurs randomly, but usually decades apart

Most or all of the world’s population lack preexisting immunity to pandemic virus

Spread of infection and severity of illness would likely be much greater than during the annual influenza season

Unlike typical influenza every winter, pandemic influenza is not seasonal

Recipe for a Pandemic

Starts with a new virus subtype– H5N1 avian (bird) flu virus in Europe, Asia, Africa

Causes severe infection– Infection is severe and can be fatal

Efficiently transmits from human to human– Not yet observed

Impact of Pandemic Influenza

Spreads rapidly throughout the world

High morbidity

Excess mortality

Significant burden on medical system

Social and economic disruption

1918-1919 Pandemic

1918 “Spanish Flu” first and worst in twentieth century (H1N1)

US deaths: 500,000

Worldwide deaths: – 40 million from the flu – 8.5 million from WWI

Other Pandemics

1957-58 Asian Flu (H2N2)– US deaths: 60,000– Global deaths: 1 million

1968-69 Hong Kong Flu (H3N2)– US deaths: 40,000– Some immunity from 57-58

All three pandemics had a huge social and economic impact

Current Situation: H5N1 Reservoir in water birds (ducks, geese, swans)

Highly lethal in poultry – ~ 100% death rate within 48 hours

December 23, 2003—February 27, 2006– 169 confirmed human cases, 91 deaths– 54% death rate among known cases– virtually all cases related to contact with infected poultry– suspected but not proven human-to-human

transmission

Contact With Poultry In Eurasia

Farming practices much different than in U.S.– Poultry housed in same areas as humans– Allowed to roam freely, exposure to infected wild birds

Consumption of sick, dead birds

Ill birds marketed in crowded marketplaces and sold/transported, often illegally

H5N1 not yet found in U.S.– Federal/state agencies testing wild birds for H5N1– Poultry industry testing every lot of poultry for slaughter

Impact Estimates for U.S. Pandemic

Deaths 89-200 thousand

0.03-0.07%

Hospitalizations 314-733 thousand

0.1-0.3%

Outpatient care 18-42 million

6-15%

Total infected 43-100 million

15-35%

Medical Management

Vaccine – will require 6-8 months to develop against a pandemic strain

Antivirals – some may be effective against a pandemic strain but supply likely limited

Trigger

The trigger to enact preparedness

plans is sustained human-to-human

transmission anywhere in the world

Challenges

Widespread: pandemic will likely occur everywhere almost simultaneously

Long-term: successive waves may last a year or more

Essential services will have to be maintained with as much as 1/3 of the workforce out sick at any one time

Take Home Message

Local response will be critical: not much state or federal support available

Need to partner and plan NOW

Purpose of today’s summit