Download Vaccination Deployment

11th Postgraduate Research Symposium
Presentation Topic :
Vaccination Deployment in Protection
against Influenza A (H1N1) Infection
PhD Student :
Supervisor :
Co-supervisor :
Shang XIA
Prof. Jiming LIU
Dr. William Kwok-Wai
Department of Computer Science
March 15, 2010
Content:
1
2
3
4
5
Page 1/17
Research Motivation & Objectives
Epidemic Infection Dynamics
Vaccine Deployment Factors
SIV model and Vaccination Simulation
Conclusion
Previous Work:
Individual Vaccination
Decision
Individual State
Transition
Population
Immunization Patterns
Epidemic Spreading
Dynamics
Global Dynamics
 Vaccination Dynamics
 Disease Diffusion Dynamics
Global Epidemic Spreading Dynamics
Disease Diffusion
Dynamics
Local-Global
Relationship
Individual State
Change
Social Contact Network
Individual Vaccination Choice
Individual
Decision Making
Local
Interaction
History Records
History Records
Environment
Evaluation
Individual
Decision Making
Disease
Infection
Individual State Transition
Page 2/17
Environment
Evaluation
Global Epidemic
Spreading Dynamics
Local Behaviors
 Social Contact Network
 Entities Infection Model
 Decision Making
Background:
 Epidemic Spreading

Virus Infection:
Individuals’ pathological infection.
 Virus Transmission:
Individuals’ contact relationship.
 Epidemic Interventions

Vaccine Immunization:
Individual immunized from virus infection.
 Contact Limitations:
Population’s contact landscape reconstructed.
Page 3/17
Research Concerns:
 Simulation Model of Infection Dynamics

Pathological Infection:
Heterogeneity of individual’s infection vulnerability.
 Contact Transmission:
Heterogeneity of Individuals’ contact frequency.
 Evaluation of Vaccination Deployment

Vaccine Availability:
 Total amount of vaccine doses.
 Starting time of vaccine releasing.
 Vaccine Distribution:
Vaccination priority of each population group.
Page 4/17
S-I-V Model
Virus Infection Model:
 Model of Simulating Virus Infection Dynamics
 Infection Status Label
Three status labels: Susceptible (S), Infected (I), Vaccinated (V).
Host Population Structure:
Population are divided into 6 Age Groups.

Heterogeneity of Vulnerability
Differentiation of Infection Rate and Recovery Rate for individual
in each age group.
 Heterogeneity of Transmissibility:
Contact Frequency within and cross each Age Groups.
Page 5/17
(Ref. 1)
Virus Infection Model (Con.)
I
V
S
I
I
V
Contact
Activities
Group 1
(0-4)
V
S
Contact
Activities
Group 3
(15-24)
(Ref.3)
S
Group 5
(45-64)
I
I
V
V
Contact
Activities
S
Group 2
(5-14)
I
S
Group 4
(25-44)
V
S
Group 6
(65+)
Page 6/17
(Ref. 2)
Vaccination Deployment:
Factors in Vaccination Deployment Plan
 Vaccine Availability
Total Amount of Vaccine
The proportion of vaccinated population of the host.
 Releasing Time
The time of first batch of vaccine being released.
Vaccine Distribution
 Vaccination Priority for each age groups.
 Vaccination by Vulnerability.
 Vaccination by Transmissibility.
Page 7/17
Vaccination Deployment (Con.)
Settings of Vaccination Deployment
1. The amount of total vaccine doses:
Low Quantity
5 million
8%
Middle Quantity
10 million
16%
Ample Quantity
20 million
32%
2. Vaccine Releasing Time:
Pre-epidemic spreading
T = 0 day
Incipient Infection Stage
T = 50 day
Infection Mass Spreading Stage
T = 100 day
Infection Stable Stage
T = 150 day
3. Vaccine Distribution Priority
Vaccination by Vulnerability
Group 1(0-4) & Group 6 (65+)
Vaccination by Transmissibility
Group 3 (15-24) & Group 4(25-44)
Vaccination by Random
All 6 Groups
Page 8/17
Simulation of Infection Dynamics
Three Stages of Infection Dynamics without Vaccination
Virus Infection Dynamics without Vaccination
S1
S2
S3
S1: Incipient Infection Stage
S2: Mass Spreading Infection Stage
S3: Stable Infection Stage
Page 9/17
Simulation of Infection Dynamics

Incipient Infection Stage
 The total percentage of infections is relatively low.
 The speed of newly increased infection is slow.
 Infection Transmission is confined within initial groups.
 Infection Mass Spreading Stage
 The number of newly increased infection are increased sharply.
 The infection positive feedback through cross group contact.

Infection Stable Stage
 The total number of infection is high.
 The increase of newly infection is stagnant.
 The cross group infection keep at a high level.
Page 10/17
Simulation of Vaccination Deployment
 The impact of the Amount of Vaccine
Page 11/17
Simulation of Vaccination Deployment
 The impact of the Vaccine Releasing
Page 12/17
Simulation of Vaccination Deployment
 The impact of the Vaccine Distribution
Page 13/17
Simulation of Vaccination Deployment
 The Impact of three Vaccine Deployment Factors
Risk of Infectious
Contact
Total Amount
Releasing Time
Increase vaccine
amount
Earlier
Releasing Time
Lowered
Vaccine Distribution
Randomly
Transmissibility
Vulnerability
Lowered: T>R>V
Risk of Successful
Infection
Lowered: V>R>T
Tipping Point of Phase
Transition
Delayed
Delayed
Infection Rising Time
Prolonged
Prolonged
Prolonged: V>T>R
Slowed
Slowed
Slowed: V>T>R
Speed of Convergence to
Stable Infection
Stable Infection
Percentage
Page 14/17
Decreased
Decreased: V>T>R
Conclusion:
 SIV Model

Pathological Infection:
Heterogeneity of individual’s infection vulnerability.
 Contact Transmission:
Heterogeneity of Individuals’ contact frequency.
 Evaluation of Vaccination Deployment Factors

Vaccine Availability:
 Total amount of vaccine doses.
 Starting time of vaccine releasing.
 Vaccine Distribution:
Vaccination priority of each population group.
Page 15/17
Reference:
1. C. Wroth and A. Wiles. Key population and vital statistics. Technical report,
Office for National Statistics, 2007.
2. J. Mossong, ect. Social contacts and mixing patterns relevant to the spread of
infectious diseases. PLoS Medicine, 5(3), March 2008.
3. E. Miller, K. Hoschler, ect. Incidence of 2009 pandemic influenza a h1n1 infection
in england: a cross-sectional serological study. The Lancet, Early Online
Publication.
Page 16/17
Q&A
Thank You Very Much!