Truvada & re-infection: answer to JP's post in another thread

[newt]

In another thread JP wrote:

"I came here tonight doing some research on the general consensus regarding re-infection and/or superinfection and came across this particular thread.  So, let's assume, for the sake of argument, that Truvada does have some effectiveness in preventing HIV infection.  Two questions:

1.  What if one were to be exposed to a strain that was resistant to the drugs in Truvada?
2.  If one is on Truvada anyway (as I am), would that imply that you might be even less at risk of re-infection??

Discuss."

Discussion

1. You are at risk of acquiring a resistant strain and compromising your use of Truvada, and perhaps other similar drugs.

2. If you are on treatment you are probably at lower risk of re-infection (but see 1 above).

Acquisition of resistant strains of HIV by re-infection is rare.  There are a handful of document cases.  Even if there are, say, 1,000 times more cases than are recorded, it's still rare. 

Infection requires quantity, quality and opportunity.  Treatment reduces quantity and quality of the virus therefore reduces the chance of infection and re-infection.  Studies suggest that in some cases - steady straight couples - HIV will not be transmitted if viral load is below 1,500.  Whether this is true for (a) casual partners (b) gay men (ie anal sex - can we have a study please) is unknown.  But in any case treatment reduces viral load which reduces infectiousness.  Re-infection, whether with a resistant or non-resistant strain seems most likely in the 1st 3 years after initial infection. 

The closer your HIV infection and treatment history to the other person the less likely unprotected sex will result in a second HIV infection.  If you and the other person have the same HIV sub-type, have an undetectable viral load, use the same treatment and have the same treatment history then the chance is prob. ZERO.  The risk rises as you and the other person's HIV situation start to differ.  The biggest factor here is viral load.

For a good overview of the science to date see HIV Superinfection vs Dual Initial Infection: What Clinicians and Patients Should Know (Medscape article, require free registration).

Different people will fairly draw different conclusions based on the same evidence.

My doc is fairly strong on this, his view is that to people with undetectable viral load regardless of treatment pose each other no risk.  He is also strong on the view that HIV-positive men screwing (other HIV-positive men) without condoms should be more concerned about getting Hep C than a second HIV infection.

- matt

[jp in la]

Great info.  Thanks Newt.  I've been reading a lot of your posts.  You're a real asset to this board.

[lydgate]

Yup, I don't worry about re-infection/superinfection, but I do worry about Hep C. (Vaccinated for Hep A and B.) My doctor said essentially the same thing as Matt's.

This is a digression from the main topic (in other words a sort of hijack); I can re-post in another thread if necessary.

The Aidsmeds lesson on Hep C transmission:

http://www.aidsmeds.com/OIs/HCV2.htm

Article read last year:

http://www.aidsmap.com/en/news/F741093C-4F71-4684-8119-C5753CDB611C.asp

Not sure I understand this article completely, clarifications appreciated. And any other studies that people should know about?

Jay

[Cliff]

To me it reads that while HCV can be transmitted sexually, it's not very common, (especially if you don't practice fisting).

[lydgate]

http://www.aidsmap.com/en/news/D80C71D1-7F71-41F0-9A90-5A1BE542973D.asp

[cjc]

yes, i thought that was very interesting and I agree that Newt is a great asset to these forums.  Thanks.   Cristy