Database Reference
In-Depth Information
The VACCINE flow is specified as
VACCINE = NON IMMUNE
∗
(
1
−
CONTRACTION
)
(2.9)
and contains the number of people vaccinated. A flow from IMMUNE to NON-
IMMUNE, captures 1.5 percent of immune people that lose their immunity
(Figure 2.15).
Consistent with the models of Sections 2.1 and 2.3, there are a series of epi-
demic outbreaks (Figure 2.16). Due to the additional features of this model, how-
ever, the numbers of immune and nonimmune people tends to stabilize and so does
the number of sick. Even though an effective immunization program is in place,
NONIMMUNE DEATH
CONTAGIOUS DEATH
NAT DEATH RATE
~
POPULATION
NONIMMUNE
CONTAGIOUS
CONTRACTION
BIRTHS
BED RATE
~
BIRTH RATE
IMMUNE LOSS
BETA
VACCINE
UNAWARE I
SICK DEATH
IMMUNE DEATH
SICK
IMMUNE
RECOVERY RATE
~
NAT DEATH RATE
POPULATION
POPULATION
NONIMMUNE
CONTAGIOUS
SICK
IMMUNE
UNAWARE I
Fig. 2.15
