Transcript No Slide Title

CDC Meeting
on Community Mitigation
of Pandemic Influenza
Nearly all slides are from Presentations made at the
Stakeholders Meeting
Community Mitigation During Pandemic Influenza in the US
Atlanta, GA
December 11-12, 2006
What actions should we
take in a pandemic?
 Mandatory or voluntary?
 Which combinations of actions?
 In what order?
 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.
Some Possible Actions
 Reporting of cases
 Isolation of Sick
 Increased sanitizing
and PPE
 Closing schools
 Social distancing of
adults in workplace
(liberal leave, telecommuting, shifts)
 Restrictions/curfew
on children/teens
 Closing nonessential offices
 Closing facilities
where people gather
 Vaccine/antivirals
when if available
 Quarantine of
contacts
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
#3
Pandemic outbreak:
With intervention
Days since First Case
Of these options, what
will we do and when?
Researchers taking two
approaches to study
effectiveness
1. Modeling influenza outbreak using
mathematical tools
2. Looking back at data from 1918 to
look for evidence that certain
interventions worked.
Different actions may be
taken in a
severe pandemic
compared to a
milder one
Epidemiology Drives Approach
Mild
Moderate
Severe
Case Fatality Rate
≤ 0.1%
0.1 - 0.5%
≥ 0.5%
Isolation
Yes
Yes
Yes
Treatment
Yes
Yes
Yes
Quarantine
No
???
Yes
Prophylaxis
High-risk individuals
High-risk individuals
Yes
School Closure
Reactive
Punctuated
Proactive
Protective sequestration High-risk individuals
High-risk individuals
Children
Community social
distancing
High-risk individuals
Encouraged
Encouraged +
selective closures
Workplace protections
Encourage good
hygiene
Social distancing
Aggressive social
distancing
Liberal leave policies
Confirmed influenza
Influenza-like illness
ILI and/or sick family
members
What some models tell us
about actions to reduce
pandemic flu spread
Value of combining strategies –
Longini model
70
60
50
40
30
20
10
0
Clinical attack rate
Antiviral stockpile needed
Base case (Ro=1.9)
Generic social distancing
School closure
School closure + generic social distancing
60% Case treatment + 60% household prophylaxis
60% Case treatment + 60% household prophylaxis + 60% social prophylaxis (60% TAP)
60% TAP + School closure + generic social distancing
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)
What do the Modeling
Results Mean?
 Not proof of efficacy or effectiveness, BUT
offer reason for optimism regarding nonpharmaceutical interventions
 Suggest that maximal effectiveness will be
achieved by appropriate targeting of
intervention and timing (early implementation)
 Need to be evaluated based upon
assumptions and validated against
experience
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)
Not just what was done
but when it was done can
make a difference
Factors Affecting Ability of
Communities to Implement
Community Measures
 Maintenance of critical infrastructure
 Extent of social cohesion, organization and
trust
 Government stability, political will
 Communication with remote areas
 Higher population densities in cities
 Financial support, compensation
– Individuals, businesses, governments
Macroeconomic Analysis
 Preliminary macroeconomic analyses of the impact of
community-wide interventions have been done, using
several economic models
 These models predict supply-side impacts that range
from a decrease in overall economic impact as a
result of community-wide interventions, to a modest
increase in impact
 These estimates do not incorporate the costs
associated with lives lost during a severe pandemic
 If an economic value is assigned to lives lost during a
severe pandemic, community-wide interventions
result in a 5-10 fold decrease in overall cost
Recent Analyses Suggest That Community
Actions May Significantly Reduce Illness and
Death Before Vaccine is Available
Early and uniform implementation of:
 School closure
 Keeping kids and teens at home
 Social distancing at work and in the community
 Encouraging voluntary home isolation by ill individuals
and voluntary home quarantine by the household
contacts
 Treating the ill and providing targeted antiviral
prophylaxis to household contacts (if available)
 Implementing measures early and in a coordinated way
Can history tell us if community interventions
Can history demonstrate that NPIs work or don’t work?
work or don’t work?
The jury is still out, but we are getting closer to a verdict
Why does closing schools
make such a difference?
Evidence to Support School
Closure
 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
Residence
s
Workplace / Classroom Social Density
Offices
Hospital
s
7.8 feet
Elementar
y Schools
11.7
feet
3.9 feet
http://buildingsdatabook.eren.doe.gov/docs/7.4.4.xls
16.2
feet
Adverse impacts of
closing schools
Labor Status of Parents
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
18 million
5 million
8 million
9 million
16.6%
4.5%
8.0%
8.9%
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
Summarizing….
Community Mitigation Summary
 Ill persons should be isolated (home vs hospital)
 Voluntary home quarantine for household contacts
 Social distancing measures
– School closures may have profound impact
– Workplace social distancing and liberal leave NOT
closure (for most)
– Cancellation of public events
 Individual infection control measures
– Hand washing and cough etiquette for all
– Mask use for ill persons, PPE stratified by risk
– Disinfection of environmental surfaces as needed
Additional Considerations
 Planning for adverse impacts of actions
 Duration of implementation
 Intervention fatigue
 Socioeconomic disparities
 Sustained, predictable absenteeism
 Economic impact
What Can Be Done Now?
 Education of leadership in State and
local government about the need for
cross-sectoral planning
 Engagement of non-health
communities: education, private sector,
labor, NGO’s
 Examination of relevant authorities, and
scenario-based discussions of
implementation with leaders & public.
 [Seen handout on 13 recommendations]
It is better to have approximate
answers to the right question
than to have the exact answer
to the wrong one.
Irene Eckstrand, NIH