Transcript No Slide Title

Community Mitigation
of Pandemic Influenza
What Key Stakeholders Need to Know
Poudre School District
Board of Education
November 13, 2007
What is a flu pandemic?
 Influenza pandemics occur when an
animal flu virus—usually a bird flu
virus—that has never infected people
alive today changes in ways that it can
– Infect humans
– Spreads easily between them,
causing illness throughout the world.
What is a flu pandemic?
 Pandemics are natural events that
happen about 3 times per century
(in 1918, 1957, and 1968)
 They can be mild (not much worse
than a bad seasonal flu outbreak)
or severe (killing millions all over
the world)
Infectious Disease Deaths in
the 20th century
Deaths per 100,000 per year
United States, 1900-1996
1957
1968
1918
JAMA.1999; 281: 61-66.
Currently we can’t stop a
pandemic
 We can’t stop a pandemic, but we can
lessen the harm through control
measures
Without control measures
Impact
With control measures
Weeks
What actions should we
take in a pandemic?
 Mandatory or voluntary?
 Which combinations of actions?
 At what point in the outbreak?
 What evidence is there that these
actions will work?
Potential Tools in Our
Toolbox
 Our best countermeasure – vaccine – will
probably be unavailable during the first
wave of a pandemic
 Antiviral treatment may not be available in
sufficient quantities.
 The effectiveness of antiviral treatment is
not clear.
Recent CDC guidance
 Community
strategies
recommended for
pandemic flu
when vaccines
and antivirals are
not available
http://www.pandemicflu.gov/plan/community/community_mitigation.pdf
4 Key Community tools
1. Asking those who are ill to remain at
home
2. Asking household members of ill
persons to remain at home
3. Child “social distancing” – closure of
schools and places children gather
4. Workplace/community
Adult “social distancing
Control measures will be
based on pandemic severity
 Severity measured by case-fatality rate
(# that die / # that become ill)
as determined in region where a
pandemic begins (likely not CO, nor
even USA)
 Pandemic Severity Index created to
help communicate level of danger to the
public, similar to the well-known
hurricane index.
 For comparison,
– the case-fatality
rate of the 1918
pandemic was
2.5% in the U.S.
– the case-fatality
rate of H5N1 in
2006 was 69%
Severity Index will drive
actions
Mild
Category 1
Moderate
Category 2-3
Severe
Category 4-5
Case Fatality Rate
< 0.1%
0.1 - <1%
1%-2% or higher
Voluntary Isolation
Recommended
Recommended
Recommended
Voluntary Quarantine
Not recommended
Consider
Recommended
Dismissing classes
Not recommended Consider
Recommended
Community social
distancing
Not recommended
Consider
Recommended
Workplace protections
Encourage good
hygiene
Social distancing
Aggressive social
distancing
Why are these measures
recommended?
Two approaches to look at
effectiveness
of control measures
1. Looking back at data from 1918 to
look for evidence that certain
interventions worked
2. Modeling influenza outbreak using
mathematical tools
Looking at 1918 to see
what worked
16000
Philadelphia
St. Louis
14000
12000
10000
8000
6000
4000
2000
2
/2
2
12
/2
9
/2
2
/2
2
/2
12
/1
5
22
12
12
/8
/
22
2
/1
/
12
/2
2
11
/2
4
/2
2
11
/1
7
/2
22
/1
0
11
/3
/
2
11
/2
2
10
/2
7
/2
2
/2
0
/2
10
/1
3
22
10
/6
/
22
10
29
/
9/
22
/
9/
15
/
9/
22
0
22
Deaths Rates / 100,000 Population
(Annual Basis)
1918 Death Rates: Philadelphia v St. Louis
Date
Weekly mortality data provided by Marc Lipsitch (personal communication)
Excess Death Rates (per 100,000) - Philadelphia
250
Excess death rate
Actual
200
Estimated if no NPIs
Total Excess Death Rate
748 vs. 1040
150
100
50
28
10
1 0 /5
/1
10 2
/1
10 9
/2
6
11
/2
11
1 1 /9
/1
11 6
/2
11 3
/3
0
12
1 2 /7
/1
12 4
/2
12 1
/2
8
1/
4
1/
11
1/
18
1/
25
2/
1
2/
8
2/
15
2/
22
9/
21
9/
9/
14
0
Week ending
Public gathering ban
total
School closure
total
Business regulations
partial
partial
?
Excess Death Rates (per 100,000) - St. Louis
Excess death rate
250
Actual
200
Estimated if no NPIs
Total Excess Death Rate
358 vs. 1180
150
100
50
1/
4
1/
11
1/
18
1/
25
2/
1
2/
8
2/
15
2/
22
9/
14
9/
21
9/
28
10
/
10 5
/1
10 2
/1
10 9
/2
6
11
/2
11
/
11 9
/1
11 6
/2
11 3
/3
0
12
/
12 7
/1
12 4
/2
12 1
/2
8
0
Week ending
Public gathering ban
total
partial
Schools closed
total
total partial
Business hours altered
total
Timing is everything
 Not just what was done but when it was
done made a big difference
 Trigger to implement school closure in
current guidance is when first cases
occur anywhere in state
 Could be very controversial decision
Purpose of Community-Based
Interventions
1. Delay outbreak peak
2. Decrease peak burden on hospitals/ infrastructure
3. Diminish overall cases and health impacts
#1
Pandemic outbreak:
No intervention
#2
Daily
Cases
Health care capacity
#3
Pandemic outbreak:
With intervention
Days since First Case
What models tell us
about actions to reduce
pandemic flu spread
Value of combining strategies –
Glass model
30
25
20
15
10
5
0
Clinical attack rate
Base case (Ro ~ 1.6)
School closure alone
School closure + targeted social distancing (10% compliance)
School closure + targeted social distancing (30% compliance)
School closure + targeted social distancing (50% compliance)
School closure + targeted social distancing (90% compliance)
Why does closing schools
(dismissing students)
make such a difference?
Evidence to Support Dismissing
Students
 Children are more susceptible to flu and more
contagious than adults
 Children are believed to be the main
introducers of influenza into households.
 School closure during influenza epidemics
has resulted in significant decreases in the
diagnoses of respiratory infections, visits to
physicians, and emergency departments.
 Reducing infection in children (via vaccines)
has reduced flu rates in all ages in community
Children are in close contact at school
Workplace / Classroom Social
Density
Offices
Hospitals
7.8 feet
Elementary
Schools
11.7 feet
16.2 feet
3.9 feet
http://buildingsdatabook.eren.doe.gov/docs/7.4.4.xls
Residences
What can be done to
reduce adverse impacts of
dismissing students?
Adverse impacts
 Difficulties of working parents with no
child care provider for younger students;
impact on other workplaces.
 Loss of children’s learning
 Loss of school meal programs for
low-income children
 Loss of state funding for school districts
Labor Status of Households (U.S.)
Households with no children<18
Households with children>12
Households with children<12 and non-working adult
Working couple with children<12
62.0%
Single working parent with children<12
66 million – No children
5 million
8 million
4.5%
8.0%
18 million
>= age12
9 million
Nonworking
adult8.9%
16.6%
Source: U.S. Census Bureau, Population Division, Current Population Survey, 2003 Annual Social and Economic Supplement
http://www.census.gov/population/www/socdemo/hh-fam/cps2003.html
Possible solutions for
working parents
 Family or friends to provide care
 Volunteers to provide care to small
numbers of children (no more than 6)
 Teleworking option for parents
 Shift changes allowing parents to be
home at different times
Possible solutions for
child instruction
 Use email, web lessons, mailed
assignments, cable TV, phone calls
to continue learning
 Provide parents with homeschooling materials appropriate for
their child
Possible solutions of loss
of school meals
 Weekly parent pick-up or home
delivery of food items for child
 Other community food providers
Possible solutions for state
funding of schools
 Governor has the power to waive
state statutes and regulations in
emergency
 School districts should work now
with legislators and governor to
ensure funding of school operations
if severe pandemic sends children
home
Community Mitigation Summary
 Ill persons should be isolated
 Voluntary home quarantine for household
contacts
 Social distancing measures
– Dismissing students may have profound
impact
– Workplace social distancing and liberal
leave NOT closure (for most)
– Cancellation of public events, closure of
entertainment venues (movies, sports,etc.),
even church services may be cancelled
Key Stakeholders must
 Understand reasons for public health
recommendations
 Participate in discussions about such
interventions with a goal of reaching
consensus
 Work together to do what need to be
done to save lives.
Charlie, 45
Jessie, 40
Florence, 19
Tommy, 16
Harry, 10
Bobbie, 8
Davie, 6
Willie, 4
A Larimer County family -- all 8 died in a 10-day period, Oct – Nov. 1918
With H5N1, children have high mortality