Viral Load determining transmission rate..

[richabk]

Here's my next question...

I was once naive and believed that if you EVER had unprotected sex with someone who is positive, you will automatically get HIV. (And that's probably the best mental state to be in to make sure you ALWAYS USE A CONDOM!!)
But I read somewhere that that's not really the case - that transmission depends on viral load. The stat that's in my head is that if someone had a viral load < 1500 then there was < 30% chance of becoming infected.

Does anyone know what the figures actually are? Is there a table/graph somewhere that shows the correlation between the two?

Thanks!
B

[JackBeck]

1. There is a big difference between exposure and transmission.

While I don't have specific % or numbers, a person is most infectious right after they get HIV. In fact, one's viral load is the highest it will probably get right after contracting HIV since the virus is trying to establish itself in the body. During this time, the immune system is trying to figure out a response to the virus. Once it does, antibodies to fight the infection are created (seroconversion).

You are correct that someone who has a viral load <1500 (undetectable viral load) is less infectious. But can they still infect a partner? Absolutely. Remember, HIV is not only in our blood. It's throughout our bodies. Only 5% of HIV is in our blood. The results of a viral load test are a better judgment of whether or not a treatment is working.

[wiley]

2. You would have to factor in co-infections to approach the true rate

None of what I am about to say applies to everyone, but you still can not judge whether someone has a virus by how they look or their lifestyle or sexual orientation or apparent robustness:

Someone co-infected with hepatitis C (HCV) for example, is about 400% more likely to transmit HIV, irregardless of HIV viral load. That's what one long term, well conducted study showed. Remember also that one can have an undetectable HIV viral load according to blood sample, yet have a moderate or even high amount of virus in the semen or other bodily fluids (not really saliva or urine, however) so pull out before ejaculating, don't swallow anything, and don't let anyone come inside you to reduce odds of transmission.

You also have to consider that a person on HIV treatment with a low (i.e. under 1500) viral load can still pass on a virus that is resistant to one or more existing medications, as well as a virus that is susceptible.

It's like with many herpesviruses. You may not have any visible sores (cold sores are a herpes virus) but you can still be shedding infectious viral particles. Will you get herpes? Depends on what you're doing, your host factors, the host factors of another person, etc. Prophylaxis with acyclovir is now considered a way to reduce the chances that you could pass on certain herpesviruses during sex if you are chronically infected with herpes.

With needles, the risk factors increase, and defy any calculation. A person may not even have HIV, but sharing needles having sex with someone who uses needles can get you a nasty case of chronic hepatitis. There's a group of like ten bodybuilders at my gym that recently developed illnesses. Sharing needles and drawing out of the same vial got them all cases of HCV and HIV, even though the index case had no viral load for HIV or HCV, and no symptoms at all.

So basically you should really try to use condoms at all times when penetration is involved (oral sex between men is really not a transmission route for HIV unless there is a situation where you shouldn't be putting anything in your mouth to begin with), but you want to find a guy who doesn't have chlamydia or gonnorrhea.

Get to know your sexual partners, discuss history and risks, have fun. Treating each other with honesty and respect is one of the best prevention and reduction of transmission of disease (if you have a chronic infection) we have.