Transcript What is Pandemic Influenza? - American College of Occupational

“Pandemic Influenza,
Government, and Business:
Balancing Public Health and
Economic Risks”
Douglas Ball, MD, MA
Department of Community and Preventive Medicine
University of Rochester School of Medicine
[email protected]
Overview
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Some things about Influenza A
Some things about Pandemics
Some things about Disease Control
Planning for Pandemics
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What to expect from a pandemic.
What to expect from the Government.
What to expect from the workforce.
How to plan.
• Resources
Influenza A virus subtypes:
• 16 HA antigens (H1 to H16)
• 9 NA antigens (N1 to N9)
• Human disease historically
• HA (H1, H2, and H3)
• NA (N1 and N2)
• More recently, human disease from avian origin
• HA (H5, H7, and H9)
Two Very Important Properties
• "Antigenic drift" refers to the process of small
genetic changes that influenza viruses continuously
undergo from year to year, which necessitates the
development of new vaccines annually.
• "Antigenic shift" refers to substantial genetic
changes caused by the process of genetic
reassortment.
Avian influenza
• Influenza A subtypes that primarily affect birds.
• H5N1
• 191 human cases, ~50% case mortality rate
• New York State Department of Agriculture and
Markets
• The New York State Department of
Environmental Conservation’s Wildlife
Pathology Unit
What is Pandemic Influenza?
• Highly pathogenic for humans.
• Efficiently transmitted between humans.
• Genetically unique.
Routes of transmission
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Direct and indirect contact
Droplet
Airborne
How much transmission occurs before symptoms
are present???
WHO Pandemic Phases
Phase
Definition
1
Inter-pandemic Period
No new flu subtypes in humans
Possibly present in animals
Risk to humans is low.
2
Inter-pandemic Period
No new flu subtypes in humans
A circulating animal flu subtype poses a substantial risk of
human disease.
WHO Pandemic Phases
Phase
Definition
3
Pandemic Alert Period
Human infections with a new subtype,
No human-to-human spread, or rare instances of spread to a close
contact.
4
Pandemic Alert Period
Small clusters, limited human-to-human transmission
Spread is highly localized: Virus is not well adapted to humans.
5
Pandemic Alert Period
Larger clusters but human-to-human spread still localized: Virus
becoming better adapted to humans
6
Pandemic Period
Increased and sustained transmission in general population.
Historical pandemics
• Three pandemics occurred during the 20th
century:
• 1918-19: Spanish Flu.
• 1957-58: Asian Flu.
• 1968-69: Hong Kong Flu.
Historical pandemics: 1918-1919
• 1918-1919 (Spanish Flu)
• Strain was H1N1, with probable avian origin
• 500 million ill worldwide
• 40-50 million dead worldwide
• Attack rate: 40% of people in exposed
populations fell ill
• Case fatality rate: 2.5-5% of ill died as a result of
the illness
1918 Pandemic waves
Taubenberger JK, Morens DM. 1918 Influenza: the Mother
of All Pandemics. Emerging Infectious Diseases 2006;12:17.
1918 Pandemic distorted case mortality
Taubenberger JK, Morens DM. 1918 Influenza: the Mother
of All Pandemics. Emerging Infectious Diseases 2006;12:20.
Historical pandemics: 1957-58
• 1957-58 (Asian Flu)
• Cause was H2N2, via a re-assortment event
• 2 million dead worldwide
• Attack rate: 20-70% of people in exposed
populations fell ill
• Case fatality rate: 0.1-0.2% of ill died as a result
of the illness
Historical pandemics: 1968-69
• 1968-69 (Hong Kong Flu)
• Strain was H3N2, via a re-assortment event
• 1 million dead worldwide
• Attack rate: 15% of people in exposed
populations fell ill
• Case fatality rate: 0.1-0.2% of ill died as a result
of the illness
Pandemic features
• Great variation in mortality, severity of illness, and
patterns of spread.
• Rapid surge in cases and exponential increase over a
very brief time, often measured in weeks.
• Severe disease in non-traditional age groups, namely
young adults, is a major determinant of a
pandemic's overall impact.
• Subsequent waves more severe then primary wave.
Disease control strategies
• Vaccination
• Pharmacologic
• Prophylaxis
• Treatment
• Non-pharmacologic
• Isolation and Quarantine
• Social Distancing
• Hygiene
• Decontamination
• Personal Protective Equipment
Pandemic vaccine
• Annual vaccine is trivalent (3 strains), pandemic
vaccine will be monovalent.
• Production using current technologies would likely
take 4-5 months  may not be available before 1st
pandemic wave
• There will be vaccine shortages initially
• 2 doses may be necessary to ensure immunity
• H5N1 Vaccines are in clinical trials
Pharmacologic prophylaxis and
treatment of influenza
• Two groups of antiviral agents are available for
treatment and prophylaxis of influenza
• adamantanes
• amantadine
• rimantadine
• neuraminidase inhibitors
• oseltamivir
• zanamivir
Isolation and quarantine
• Only shown to be effective in preventing
transmission in closed settings.
• Recommended if pandemic influenza strain is
highly localized and limited.
Limitations for Influenza
• Short incubation period.
• Possible pre-symptomatic spread.
• Possible asymptomatic illness.
Social distancing and hygiene
• Limited success during past pandemics.
• Wearing masks in public apparently helpful.
• Hand washing and respiratory hygiene/cough
etiquette may help, but benefit is undemonstrated.
Decontamination
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“The influenza virus is extremely sensitive to almost any disinfectant.
However, it is very difficult to inactivate the virus if it is in organic material,
such as feces.”
Disinfectants that will kill avian influenza virus:
• Any detergent
• Formaldehyde
• Bleach
• Ammonia
• Acids
• Heating to 90ºF for 3 hours, 100ºF for 30 min.
• Drying
• Iodine containing solutions
Cardona C. UC Davis Veterinary Medicine Extension. AI Recommendations.
Available at: http://www.vetmed.ucdavis.edu/vetext/INF-PO_AI.html Accessed
February 06, 2006.
Surgical masks
• FDA Surgical Mask Approval Criteria
“A surgical mask covers the user’s nose and mouth and
provides a physical barrier to fluids and particulate
materials.”
“A surgical respirator is fitted to the user’s face, forming
a seal that provides a physical barrier to fluids,
particulate materials, and aerosols.”
• NYS DOH
“Wear a surgical or procedure mask for close contact
with infectious patients (i.e., within 3 feet).”
Ways that pandemic planning is
different
• Influenza pandemics are expected but arrive
with very little warning.
• Outbreaks can be expected to occur
simultaneously throughout much of the U.S.
• The effect of pandemic influenza on individual
communities will be relatively prolonged (weeks
to months) in comparison to disasters of shorter
duration.
Ways that pandemic planning is
different
• The number of persons affected will be high.
• Effective preventive and therapeutic measures,
including vaccine and antiviral agents, are likely
to be delayed and in short supply.
• There may be significant shortages of personnel
in other sectors that provide critical public safety
services.
A question of risk
Risk =Hazard X Probability
Which model?
• Department of Health and Human Services
Pandemic Plan (and NYS DOH plan):
• Very detailed, mild and severe scenario.
• Duration of absenteeism not quantified.
• 10% worker absence for child care and care of
ill relatives suggested.
Which model?
• Congressional Budget Office
• Comprehensive; mild and severe scenarios.
• Includes numbers of days workers expected to
miss.
Which model?
• FluSurge 2.0
• A CDC modeling tool.
• Does not model the DHHS-stated planning
assumptions.
Comparison For Monroe County
• DHHS Assumptions:
• 30% overall attack rate.
• 2.5% case mortality rate.
• For population of 738422, there will be 5, 538
deaths.
• FluSurge 2.0
• 35% overall attack rate.
• For population of 738422, there will be 1,158
deaths in the worst case scenario.
Congressional Budget Office
Severe Pandemic Projection for Monroe County:
• 220 thousand will fall ill (30% of total population)
• 5,500 will die (2.5% of those who fall ill)
• Workforce Effects:
• 30% of the workforce will be affected.
• For surviving ill, average time away from work will be
3 weeks.
• 2,750 workers will die (0.75% permanent reduction
of the workforce).
Likelihood of a pandemic
• Pandemics have occurred an average of every 24 years
over the last 300 years.
• Large HPAI pandemic may be a harbinger of a human
pandemic:
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now endemic in eastern Asia.
expanding mammalian host range and geographic extent.
high case-fatality rate.
two recent mutations ->better adapted to humans.
Travel restrictions
• Point-of-entry screening.
• Isolating persons and identifying and quarantining
contacts.
• Limiting or canceling nonessential travel.
• Isolating ill arriving passengers on flights and
quarantining passengers and crew.
• Closing mass transit systems and interstate bus and
train routes.
Containment strategies for different
groups
1) Individuals or groups of exposed persons:
isolation and quarantine.
2) Entire communities
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Promotion of community-wide infection control
measures including respiratory hygiene/cough
etiquette, hand hygiene, and avoiding public
gatherings.
Snow days and self-shielding
Closure of office buildings, shopping malls, schools,
and public transportation are potential community
containment measures during a pandemic.
Workforce
• Marked reduction in workforce due to:
• Fear of contracting illness and fear related
behaviors.
• Child and elder care obligations and absences.
• Personal illness and absence.
• Deaths.
Common sense planning
• Identify essential employees and other critical inputs.
• Provide sufficient and accessible infection control
supplies in all business locations.
• Establish policies for employees who have been
exposed to pandemic influenza, are suspected to be ill,
or become ill at the worksite.
• Anticipate employee fear and anxiety, rumors and
misinformation, and plan communications accordingly.
Other less obvious issues
• Establish policies for flexible worksite and flexible
work hours.
• Establish policies for preventing influenza spread at
the worksite.
• Evacuate employees working in or near an affected
area.
Other less obvious issues
• Establish policies for employee compensation and sickleave absences unique to a pandemic:
• “non-punitive”.
• “liberal leave”.
• Self-shielding.
• Caring for well children home from closed schools.
• Quarantine.
Players on your team
• Your Company
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Line Management
Human Resources
Occupational Health
Logistics
Information Technology
• Public Health Department
Local Health Departments
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Monroe County Health Department
COMMISSIONER:
Andrew Doniger, MD, MPH
PHONE: 585-753-2991
E-mail: [email protected]
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Livingston County Health Department
PUBLIC HEALTH DIRECTOR:
Joan H. Ellison
PHONE: 585-243-7270
E-mail: [email protected]
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Orleans County Health Department
PUBLIC HEALTH DIRECTOR:/
DIR. OF ENVIRON. HEALTH:
Andrew Lucyszyn
E-mail: [email protected]
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Ontario County Comm. Health Services
PUBLIC HEALTH DIRECTOR:
Jody Gray, RN, MSN
PHONE: 585-396-4343
E-mail: [email protected]
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Genesee County Public Health Department
PUBLIC HEALTH DIRECTOR:
Christopher M. Szwagiel, MS, MPH, DrPH
PHONE: (585) 344-2580 x 5496
E-mail: [email protected]
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Wayne County Public Health Service
PUBLIC HEALTH DIRECTOR:
Linda Michielson, RN, MS, ANP
PHONE: 315-946-5749
E-Mail: [email protected]
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Wyoming County Health Department
Interim PUBLIC HEALTH DIRECTOR:
Gregory Collins, DO
PHONE: (585)786-8890
E-mail: [email protected]
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The New York State Association of County Health
Officials
www.nysacho.org/Directory/directory.html
Resources
Department of Health and Human Services Pandemic Plan:
www.cdc.gov/flu/pandemic/
New York State Department of Health:
www.health.state.ny.us/diseases/communicable/influenza/pandemi
c/index.htm
Federal Pandemic Planning Resources Including Checklist:
www.pandemicflu.gov
The Occupational Health Disaster Expert Network
ohden.sph.unc.edu