Modeling Epidemics

Question 1

SIR

Answer 1

• model for a small, contagious epidemic
• consider:
  1. N - size of size
  2. S - population with large number of susceptible people
  3. I - a small number of infected people
  4. R - number of recovered people

• assume no births and deaths (which implies that infectious disease doesn’t cause death, and that there are no natural births and deaths- meaning it is a short period of time)

Question 2

Beta depends on:

Answer 2

1. The rate at which susceptible and infected people come into contact
2. Probability of the transfer of infection in the event that susceptible and infected come into contact

Question 3

The basic reproduction number

Answer 3

Ro
•so far we’ve been dealing with Ro>1
- the greater the Ro is, the more rapidly the epidemic spreads

Question 4

Prevalence

Answer 4

(More specifically point prevalence) is defined in the context of an epidemic model as the number of existing infected cases of this disease at any tine instant, per unit population size (often expressed per 100 000 of the population).
- prevalence per 100 000 people = 1/N x 100 000

Question 5

Incidence

Answer 5

Rate of new cases

Question 6

Prevalence

Answer 6

Number of actual cases