If herpes transmission rates are low without symptoms, why do so many people have herpes?

[sprantil]

Hi all! I have still a few things I'm insure of about herpes transmission. If someone without condoms or suppression can transmit it to someone by 4% if you're a female and 10% if you're a male, which are kind of low numbers, why is herpes so common?

[CityofAngels]

I believe the logic might go something like this:

 

Firstly, the odds of a woman contracting genital herpes are significantly higher than that: around 10% without either suppressive therapy or condom usage. Consequently, many more women have genital herpes than men. For women of any ethnic group, around 25% will have genital herpes. For men of any ethnic group, the figure is roughly 10%.

 

There are many factors that go into determining someone's overall risk to genital herpes, among them immune system function and prior exposure to HSV-1 (although those are only 2 such factors).

 

The transmission rate of 4% per year from man to woman is admittedly low--for any individual given year. However, the probabilities are cumulative, meaning that they increase from year to year. Think of it this way: if you flip one quarter once, the probabilities are 50/50 that it will come up heads or tails. Let's say it comes up tails. Flip it again. The odds are still 50/50 that for that individual instance, it will come up tails. But the odds of getting a *sequence* of tails-tails are only about 1/4. Same with genital herpes. The probability that a man will contract it in any given year are only about 4%. Yet the probability that he will have a *sequence* of year after year in which he does not contract it, is somewhat less.

 

Now, people will tell you they have know individuals who have been together for what, years and decades, who have never contracted it from their partner. That is not a counterargument to my point. The fact that some individuals can go years or even decades without contracting herpes from their partner can be entirely accommodated within the concept of mathematical probability. In fact, according to statistics it is bound to happen. Yet the point is, such occurrences are extremely rare, as are the occurrences in which a person contracts herpes from a one-time occurrence, or a small but fixed number of sexual encounters.

 

Hope this helps.

 

[CityofAngels]

Also please note this is a simplified treatment of the issue purely based on considerations from mathematical probability. As I said above, the reasons why some individuals contract herpes after a relatively short amount of time, and while others can go years without contracting it, are myriad.

[WCSDancer2010]

Actually, the rate will stay at 4% (or 10%) per year no matter what. Statistics of this sort don't change. Just like every time you flip a quarter, your odds of getting Heads or Tails will ALWAYS be 50% no matter how many times you flip the coin. The stats are based on a couple having sex 2 times a week.

 

The reason for the numbers is 2-fold.

 

80% of people with H don't know they have herpes .. so many of them may not realize that the "little rash" they have is H when they have sex. I was one of those people and I gave it to my (then) husband about 2 years into our marriage. :(

 

The other reason is that MILLIONS of people are having sex every day ... There are about 500,000 new cases of Herpes each year in America ... so when you think about it, the numbers are not *that* high. ;)

 

Just looked it up... there are 208 million people aged 16-64 ... who on average are having sex about 118x/yr (figure is for age 16-45 but it's what I could find) = 24,544,000,000 sex acts/yr ... give or take a few million ... so that 500,000 new cases is pretty damn small if you think about it ;)