Sunday, May 13, 2007

Sex for Health Part II

The author is correct in his assumption that more sex can indeed bring down the growth of STDs in society:
I did some more math work, taking into account that that STD carriers theroetically have more sex, and the original author may indeed be correct (under one circumstance, anyways)

The number of new infection=p*c*f*i
p=probability infecfted sleeping with uninfected person
c=chance of it spreading per contact
f=frequency: number of times infected person has sex compared to uninfected
i=number of infected people

f and p are related inversely. If f increases, then p decreases...the more often infected people sleep (as a whole), the less likely an individual infected person sleeps with an uninfected person.

I modelled this with:
where x is the total number of people in the population. x-i is the number of times uninfected people have sex per f times for an infected person.
IE, if there are 10 infected people and 30 uninfected, and the infected sleep 3 times for every 1 of the uninfected, then the probability of sleeping with an uninfected individual is 1/2 (40-10=30, divided by f*i=30+30=60)

This is the chance of any individual sleeping with an uninfected on any given time.

SOOOOO, putting it all together:
divided by
is the number of new infections

Put random numbers in for c, x, and i, and let f be favorable. As f increases, the number of infections increases. f=number of times infected people have sex/number of times uninfected people have sex.
So, the author is right: Holding ALL ELSE EQUAL, if uninfected people have more sex, the number of infections is wrong.

Yes, I was wrong

No comments: