Three Papers on PODSSNS Distribution, Vaccination Strategies, and POD

Throughput

Presented by Marty O’Neill II

Resource Allocation for Demand Surge Mitigation during Disaster

ResponseHina Arora, T.S. Raghu, & Ajay Vinze

The First Paper:

Modelpopulation, regions, and stockpile

There are T-1 regions and one SNS stockpile location.

k is a node in the system where k=1 is the stockpile and k=2,3,…,T are the regions

Pk is the population of region k, and P is the population across all regions.

mk is the susceptible population of region k

GARk is the gross attack rate of region k

nk is the expected number of infected individuals, and nk = GARk * mk

S courses of antivirals are available. Treatment requires 1 course. Prophylaxis requires 4 courses.

Sk is the maximum stockpile allocation for region k using CDC’s equitable allocation approachSk = (Pk / P) * S

Modelprophylaxis & outcomes

For each region k, pPxsk is the proportion of mk provided with prophylaxis treatment. This will consume a total of 4 * (pPxsk * mk) courses of antivirals from the stockpile.

Health outcomes w: wd – death wh – hospitalization wo – outpatient care wn – ill, but seek no medical care

Using The Economic Impact of Pandemic Influenza in the United States: Priorities for Intervention from EID by Meltzer, Cox, & Fukuda,

The number of expected health outcomes nw,k for each region k isnd,k = 0.00202 * nk

nh,k = 0.00791 * nk

no,k = 0.46276 * nk

nn,k = 0.52731 * nk

Modelprophylaxis cost/benefit analysis

ep,w is the expected effectiveness of prophylaxis averting a particular health outcome w

vw is the value saved per person by averting a particular health outcome w

Total savings:

Total cost:

Susceptibles are then reduced by mk * pPxsk * ep

… which leads to a reduction in expected infections and expected health outcomes due to infection.

Questions

How much of the CDC stockpile should be pre-allocated?• Current policy is 100%• 60, 80, & 100% were examined• Lower vs. higher GAR examined• When stockpile has enough to go around, all thee cases perform

equally well.

How does GAR impact cost and savings?

• Lower vs. higher GAR examined• When stockpile has enough to go around, all thee cases perform

equally well.

How does implementation of transshipment impact savings?• Transshippment vs. no transshipment

Proportion of max savings vs. Proportion of Total Infectedlower GAR (above) and higher GAR (below)

SNS

SNS

Comments

• Paper studied Influenza PODs, but with focus on possibility of exponentially growing pandemic

• How could their methodology of studying transshipping be applied to cost/benefit analysis of different mobile/temporary POD scenarios for Anthrax or Smallpox?

A Dynamic Network with Individual Mobility for Designing Vaccination

StrategiesLia Mao & Ling Bian

Focus is on Influenza vaccination

The Second Paper:

Modeled Social Network

Day time

Night time

daytime

(These are the same.)

Intercommunity travelersare assigned communitiescloser to each other usinga distance-decay function

Note: This is in geographic space.

Vaccination Methods Modeled

• Travel-based – target intercommunity travelers

• Contact-based – target individuals having larger numbers of direct contacts

• Random – individuals are randomly selected for vaccination

Vaccination is assumed to occur BEFORE outbreak begins.

Different Networks Modeled(with N = 5000)

* Maximum Connected Component

*

Vaccination Results% Infected

Under-connected Network Over-connected Network

Vaccination ResultsSpatial Patterns

Travel-based Contact-based Random

Ove

r-co

nnec

ted

Und

er-c

onne

cted

Conclusions from Paperand Final Notes

• Travel-based strategy shows best results.• PODs can be established at transportation

hubs.

• Travel-based works best because of model assumptions.

• Constraints in this model were on vaccination supplies, not time.

Modeling and Optimizing the Public-Health Infrastructure for Emergency

ResponseEva K. Lee, Chien-Hung Chen,

Ferdinand Pietz, & Bernard Benecke

Focus is on “mass dispensing of medical countermeasures for protection of the general population.”

Last (but not least)…The Third Paper:

Within a POD1. Assess client health status2. Assess client eligibility to receive service3. Assess implications of each case and refer for further

investigation if necessary4. Counsel clients regarding services and associated

risks5. Administer services6. Educate clients regarding adverse events7. Document services8. …

Example POD Flowchart

POD Placement Methodology

1. Given the population, how many PODs are needed?All PODs shouldn’t have to be equal in number of booths.

2. Where should we place these PODs?

Population Distribution/Location Methodology

Census Population Data in Census Blocks

Population Density of each

block

Overlay Grid(square mile)

Calculate Population of Each Grid Cell

Using Densities

Problem:Assumes population’s spatial distribution is uniform within census blocks

POD Location Model

Overall Comments

• Resource distribution, allocation, and reallocation are currently being studied for SNS distribution.

• Results of computational models underscore importance of successful mitigation through treatment.

• POD throughput analysis and optimization has been investigated. However, not enough attention has been paid to the geographic distribution of the population’s service requirements.