Information Technology Reference
In-Depth Information
Our model is based on HPV transition between people due to heterosexual
contact. We assume that women infected by HPV could recover and acquire
temporal immunity or could be long-term colonized by the virus and could then
develop cancer. The model helps us understand the process and predict possible
realizations and allows us to give suggestions on how to cope with an outbreak.
We test the following scenarios:
a) no obligatory vaccination or vaccination of 14 years old girls (before sexual
debut - the optimal srategy according to [4], [4],[3], [1], [16]);
b) with 50% or 75% of sexuality (linear) increase;
c) for different health care progress in effective screening frequencies of testing
for cell pathology until frequency up to every 2
.
5or7
.
5years.
3 Methods and Model Design (Code Is Available [20])
−
We model part of Polish population which is sexually active (15
64 years old).
We assume a temporal naturally acquired immunity and lifelong vaccine acquired
immunity, with given e
cacy. Male population is divided into 3 stages: Suscep-
tible (Sm), Infectious (HPVm), Recovered (Rm) and population is dynamic due
to natural birth and death rates. For women, apart from Sw, HPVw, Rw, ad-
ditional stages Long-term colonized (StageIIw), Vaccinated (Vw) and Having
cancer (Cancer), are allowed and all except Cancer are divided into different
age groups. We also introduced changing of society by aging, birth and death
(which was set to affect older groups much more than younger ones). We assume
that around the age of 65 people are not changing partners, so death rate means
not natural death, but rather removing from sexually active society. We are still
tracing women above 65, who were already infected (in stage HPV or StageII)
and can develop the cancer. We also allow dying in sexually active lifespan due
to some other cause, with age-dependent death rate. Birth, which is actually to
be understood as turning 15 years and potentially beginning a sexual life is in-
terpolated from register data for time up until 2013 (now) and extrapolated for
near future. In our model, Polish society is slowly aging in waves (as it seems to
be happening in reality, due to specific demographic structure (Figure 4(a),4(b)).
Medical properties of cancer developing are known to be age-dependent as well
as sexual activity, so we decided to choose age groups with respect to data form
reports. We used reports of Finish sexuality, in which the society is divided in
groups of 5 years intervals. Cancer development properties were set up seperatly
for all age-cohorts. As a trade-off for having the smallest numbers of groups,
but caching main differences in behavior, we choose to devide women into the
following age cohorts.
1) 15
−
19 (initiation of sexual live)
2) 20
−
24 (most active sexual group)
3) 25
−
34 (stabilization of sexual live)
4) 35
−
64 (sexual stagnation and stronger susceptibility to cancer)
5)
≥
65 (no sexuality and cancer development)
