Transcript Influenza: From Basics to Pandemics Why Worry? Why Plan? Influenza is Serious! •Annual deaths: 36,000 •Hospitalizations: >200,000 Who is at greatest risk for serious complications? Persons Persons 65 and.

Influenza:
From Basics to
Pandemics
Why Worry? Why Plan?
Influenza is Serious!
•Annual deaths: 36,000
•Hospitalizations: >200,000
Who is at greatest risk for serious complications?
Persons
Persons
65 and older
with chronic diseases
Infants
Pregnant
Nursing
women
home residents
Influenza= Flu
Respiratory infection

Rapid onset of Fever, Chills, Body aches, Sore
throat, Non-productive cough, Runny nose,
Headache
Takes 1- 5 days from exposure to beginning of
symptoms
Contagious maximum 1-2 days before to 4-5 days
after onset of symptoms
Peak usually occurs December through March in
North America
Influenza Virus:
How it spreads
Close contact (<6 feet) with sick person who is
coughing or sneezing by way of droplets
OR
Touching a surface contaminated by respiratory
secretions and getting the virus into mouth, nose
or eyes.
Influenza Epidemic Pattern
Epidemic: Higher than normal number
of cases of a disease in a community

Also called “outbreak”
Abrupt onset in a community: overall
attack rate 10-20%
Sharp peak in 2- 3 weeks, lasts about 56 weeks
Influenza Epidemic Pattern
First sign: Increased #
children with febrile
respiratory illness
Followed by: increased
hospitalization rate for
pneumonia/COPD/CHF/cr
oup
Absenteeism a late
indicator
Influenza background
Flu strains typically found in many
mammals

Birds and swine common hosts for what
ultimately become human flu viruses

Flu hosts usually develop an immunity to
the virus after infection
How does the virus
survive?
Minor mutation in flu virus is referred to as
drift.
A much bigger change is referred to as a
shift

Shift: Major change = new subtype =
Pandemic potential
Pandemic – An epidemic that spreads
around the world
Influenza types
Type A (Party Girls)




Animals and humans
More versatile, more virulent
Epidemics and pandemics
All ages
Type B (DAR)



Humans only
Milder epidemics
Primarily affects children
Key Influenza A
Viral Features
Two surface glycoproteins (major antigens)
Hemagglutinin (HA)
HA

•
Site of attachment to host
cells
Antibody to HA is protective
Neuraminadase (NA)
NA
•
•
Helps release virions from
cells
Antibody to NA can help
modify disease severity
The Pandemic
Influenza Cycle
Rapid transmission worldwide


Multiple waves of disease over a 18-24 month
period
Occurrence of cases outside usual season
High attack rate and high death rate

All age groups, especially young adults
Cycles every 10-40 years

Last pandemic was mild-1968
How does the virus
survive?
Minor mutation in antigens of flu virus is
referred to as drift.
A much bigger immunologic change
(mutation) is referred to as a shift

Shift: Major change = new/novel subtype =
Pandemic potential
Pandemic – an infectious disease occurring
over a wide geographic area targeting a high
percentage of the population
Mechanisms
of Antigenic Shift
Non-human
virus
Human
virus
Reassortant
Virus –
1957, 1968
The Pandemic
Influenza Cycle
Rapid transmission with worldwide outbreaks;
multiple waves of disease over a 18-24
month period
Occurrence of cases outside the usual
season
High attack rate for all age groups, with high
mortality rates, esp for young adults
Cycles 10-40 years. Last pandemic was mild,
1968
Influenza Pandemics in
the 20th Century
Credit: US National Museum of Health and
Medicine
1918: “Spanish Flu”
A(H1N1)
1957: “Asian Flu”
A(H2N2)
1968: “Hong Kong Flu”
A(H3N2)
20-40 m deaths
1-4 m deaths
1-4 m deaths
675,000 US deaths
70,000 US deaths
34,000 US deaths
Impact of Past Influenza
Pandemics/Antigenic Shifts
Pandemic, or
Antigenic Shift
Excess Mortality
Populations
Affected
1918-19
Spanish Flu
500,000
Persons <65
years
1957-58
Asian Flu
1968-69
Hong Kong Flu
70,000
Infants, elderly
36,000
Infants, elderly
1977-78
Russian Flu
8,300
Young (persons
<20)
The social and medical importance of
the 1918-1919 influenza pandemic
cannot be overemphasized
About half of the 2 billion people living
on earth in 1918 became infected
At least 20 million people died
1918 Spanish Flu:
United States
20 million flu cases were reported
and almost ½ million people died
“It is impossible to imagine the social
misery and dislocation implicit in
these dry statistics.” America’s Forgotten
Pandemic, Alfred Crosby
H5N1 “Avian” flu
The current strain of avian flu, H5N1,
represents a major shift
When the major shift “waits” 50-75
years:
Community has very little or no
immunity/protection
 Entire population is a ripe target

Current outbreaks for H5N1 Avian Flu
in poultry and birds are largest ever
documented
Duration of outbreak creates potential
for genetic change that could result in
person-to-person transmission
20
Nations With Confirmed Cases
H5N1 Avian Influenza (July 7, 2006)
Avian Influenza A
Viruses
Wild waterfowl are natural reservoir



Infect respiratory and gastrointestinal tracts of birds
Usually do not cause disease
Genetic re-assortment is frequent
Viruses are present in
respiratory secretions, feces

Can survive at low temperatures
and low humidity for
days to weeks, and in water
H5N1 in Humans –
2003-2006
As of June, 2006: 256 cases, 152 deaths




Ten countries
Millions have been exposed to poultry
50% cases in persons <20 years old
90% cases <40 years old
Sporadic, with occasional clusters

All lived in countries with poultry outbreaks
Most had touched or handled sick poultry
Few cases of probable, limited human-to-human
transmission
Global Status of Current
Pandemic Threat
World Health Organization (WHO) defines 3 major
periods (broken into 6 phases) of increasing
human infection with new flu virus:

Interpandemic (no human infection)

Pandemic Alert (limited human infection)

Pandemic (widespread human infection)
Presently at Pandemic Alert (Phase 3)

“Isolated human infections with a novel influenza strain
[H5N1] with no (or rare) person-to-person
transmission”.
“The pandemic clock is
ticking, we just don’t know
what time it is”
Assumptions About
Disease Transmission
No one immune to virus

1 out of every 3 people will become ill
People may be contagious up to 24 hours before they
know they are sick

Most will become ill 2 days (range 1-10) after exposure
People are most contagious the first 2 days of illness

Sick children are more contagious than adults

On average, each ill person can infect 2 or 3 others (if no
precautions are taken)
Social and Economic Impact
Assumptions
Absenteeism

At the peak of a 6-8 week wave, ~40% of employees
may be absent



Illness
Caring for sick family member
Fear
Hospital demands


Estimated >25% more patients than normal needing
hospitalization
Hospitals will not be able to take everyone they normally
would!
Federal or other outside
volunteers and resources?
Volunteers will be needed
in their own communities
Communities should plan to respond
with their own resources,
not rely on outside help
HHS Estimated Medical Burden
in Tennessee
(Pop: 6 million)
Characteristic
Moderate
Severe*
Illness (30%)
Outpatient Care
1.8 million
900,000
1.8 million
900,000
Hospitalization
17,300
198,000
ICU Care
2,575
29,700
Mechanical
Ventilation
Deaths
1,300
14,850
4,180 (0.2%)
38,060 (2%)
*HHS Recommends that states plan for severe scenario
Estimated Medical Burden
in Knox County
Characteristic
Illness (30%)
Moderate (0.2%) Severe (2%)
119,000
119,000
Outpatient care
59,500
59,500
Hospitalization
1,190
11,900
ICU (15% hosp pts)
180
1,800
Mechanical
ventilators (50%
90
900
240
2,380
ICU pts)
Deaths
HHS Assumptions:
Objectives of Pandemic
Planning & Response
Primary objective:

Minimize sickness and death
Secondary objectives:

Preserve functional society

Minimize economic disruption
There is not complete consensus on the
proper order of these assumptions!
Surveillance:
Traditional responsibility of Department of Health
Syndromic Surveillance: Monitor 911 calls,
emergency department visits, doctor visits, and
school absenteeism
Sentinel health care providers: Testing and
active surveillance for patients with ILI
CDC planning additional national surveillance
activities
Disease Control:
Early Stage
Initial objective: slow spread of disease
Isolate sick patients
Quarantine exposed healthy persons.
Housing, health care, food, psychological,
spiritual, needs must be met
 Legal measures possible but will rely on
voluntary cooperation

Once beyond initial cases,
shift strategy to
“Stay home
when you are sick”
Disease Control: Social Distancing
Once pandemic begins in US, gatherings of
>10,000 people subject to cancellation
During local waves: Suspend discretionary
public gatherings of >100
School and Daycare Closure
Key to slowing spread is to disrupt nodes of
intense transmission
Preschool through 12th grade are such nodes

Attack rates of 40% possible in schools during
ordinary flu season
Pre-emptive school/large daycare closure is
central component of proposed federal
strategy
School and Daycare Closure
Key to slowing spread is to disrupt nodes of
intense transmission
Preschool through 12th grade are such nodes
(Attack rates of 40% possible in schools
during ordinary flu season)
Pre-emptive school/large daycare closure is
central component of proposed federal
strategy
Infection Control:
“Cover Your Cough”
“Respiratory hygiene”, “Cough etiquette”, “Good
health manners”
Infection Control
Assumptions
Survival @ 82oF, 3549% humidity (longer if
lower temp, lower
humidity)

48h on hard non-porous
surfaces

8-12h on cloth, paper, tissue

Susceptible to EPA registered
disinfectants
Transmission: Dropletsurgical masks protective
Infection Control
Assumptions
Airborne transmission (less common, but
much more infective: 10-100 x vs. droplets).
Surgical masks NOT protective
Aerosol-generating procedures (e.g., intubation,
suctioning, nebulizer treatment, bronchoscopy,
intubation, BiPAP, CPAP): N95 respirators
should be used
What About Vaccine?
Production minimum 6 month process:


Process requires eggs (93 million!) but virus is lethal to birds
Unlikely to be available before 1st pandemic wave
HHS priority groups



Military and Vaccine manufacturers
Healthcare workers with direct patient care
Persons at highest risk for complications
Two doses needed for protection
What About Antivirals?
Tamiflu
Anti-viral agent,
currently in short supply
Could be used in one
area of world to contain
first human outbreak
Resistance described
Should be used within
48 of infection
Unlikely to markedly
affect course of
pandemic
Tamiflu ≠ Preparedness
Vaccine/Antiviral
Distribution
Prioritization of personnel : based on
level of patient contact
Vaccine will be administered by public
health personnel over months
Prioritization determined by Feds and
may change
Guidance for Planning
Because resources will be
limited…
Contingency planning should include:
 Planning for absenteeism: ~40%
 Hygiene products and
education in the workplace
 Supply shortages
 Home offices for critical
personnel
 Sick leave policies compatible
with state recommendations
Internal and External
Communication networks
Detailed communications plans needed:


Internal- Ensure employees know panflu policy,
communications plan, their specific role, esp in
surge capacity
External- POC with Health Department

Info via KCHD website, Broadcast FAX, Email, Media
Coordinate with like organizations
to develop/coordinate emergency plans
Communicate with other facilities affected by
yours
Infection
Control:
Education
Signage to educate personnel and patients
Adequacy of surgical masks for patient
contact not involving aerosolization
procedures
Possibility of using surgical masks over
reusable N95s as well as goggles/face
shields for high-risk procedures
Establishing regularly scheduled
environmental cleaning
Infection Control:
Using PPE
Follow protocol for donning and removing PPE
•
Provide hand hygiene
materials (>60% alcohol)
Provide tissues &
instructions when to use
them: proper disposal;
importance of handhygiene
Surveillance for those at
work

Develop screening for
employees with flu-like
symptoms
Develop sick leave policy specific for
panflu: liberal and non-punitive
Determine when ill employee may
return to work
Sick Leave policy
Liberal and non-punitive
Staff who become ill at work
Recovering staff- when to return
Symptomatic but functional staffallowed to work?
Reassignment of personnel at
increased risk for flu complications
Offer annual flu vaccine
Surge Capacity:
Staffing Shortages
Identify minimum number employees
and categories required for essential
operations
Temporary help
Cross train employees
MOAs with other facilities
Surge Capacity:
Supplies
Estimate needs for
consumable resources
Primary Plan & Contingency Plan
Detailed procedures for supply acquisition
 Normal channels exhausted: have a backup

Workforce Support
Psychological and physical strain on
personnel responding in emergency
situation
Psychological stress for families
Plan for your staff to have adequate
Sleep, food
 Access to psychological
and spiritual support

Pandemic flu today
Despite . . .


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Expanded global and national surveillance
Better healthcare, medicines, diagnostics
Greater vaccine manufacturing capacity
New risks:

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Increased global travel and commerce
Greater population density
More elderly and immunosuppressed
More daycare and nursing homes
Bioterrorism
Steps YOU can take
Practice good personal hygiene:
Avoid hand contact with your mouth, eyes,
and nose
 Wash hands regularly and often
 Use paper towels to turn off the faucet and
open the restroom doors

Steps YOU can take
Carry a supply of hand sanitizing gel – use
it regularly
 60%-95% alcohol-based sanitizer


Cover your cough
Steps YOU can take
Get a flu vaccination when offered
When flu season arrives- avoid contact
with infected people, limit social activity
Consider wearing surgical mask and/or
disposable gloves when in public
Steps YOU can take
Be aware in public of potentially infected
surfaces

Check-out counters, door knobs,
pay phones
Regularly disinfect commonly used surfaces


1:10 bleach solution
EPA registered disinfectant
Steps YOU can take
Illness preparation:



Maintain supply of electrolyte
drinks (Gatorade)
Antipyretics (Tylenol)
Prescription medications
Stock up on water and foodone week’s supply

Minimum: One gallon per
person per day


Store in plastic, not glass
Food that won’t spoil
Steps YOU can take
Make plans for child care in the event
schools close 6-8 weeks
Plan for eldercare/pet care
Family Planning is
Essential
Good advice for any disaster, not just
pandemic influenza!!!
See Family Planning Checklists
Pandemicflu.gov
 RedCross.org
 Ready.gov

Resources
PandemicFlu.gov
CDC.gov/flu/avian
RedCross.org
www.nyhealth.gov
Knoxcounty.org/health: if you want to be put
on “Pandemic Alert Email” list
For questions regarding pandemic influenza
planning, please call 215-5171 or email:
[email protected]