HIV prevalence in blood only 2-4%?

[Common_ground]

Ive been reading about the amount of HIV in the bloodstream which to me seems just to be a small part, so then how do docs and scientists knows if the meds are
really working by just being able to look at the blood? Is there are facts on "how much" HIV the meds are being able to surpress/delete from the body?

[newt]

how do docs and scientists knows if the meds are
really working by just being able to look at the blood

An important question.

Blood tests are convenient for doctors and patients and therefore used for lots of things medical. Much effort goes into making sure they are reliable and reflect what they are trying to measure.

You can test HIV in other parts of the body, for example spinal cord fluid, genitals, gut, but the tests are inconvenient and sometimes carry risks (biopsy, spinal tap anyone?).

There's lots of research on viral load in the gentials and central nervous system, and these show that viral load in the blood and other parts of the body are the same after a few months of treatment (there are sometimes modest but usually unimportant variations).

I'd post some links to the research but have to go pick the broad beans, maybe if people want these will do so when I'm back from the fields.

- matt

[Common_ground]

I was hoping to get an answer from you Newt.

If you find the time, please post some links, thx.

The question originally came up when I read up on the "blood brain barrier" thing and meds able to cross that barrier. Made me think of choosing another regimen than Atripla even thou getting UD. Any thoughts?

[eric48]

Current CNS Penetration-Effectiveness (CPE) 2010 ranking

can be found here
http://www.natap.org/2011/CROI/croi_139.htm

(you will have to scroll down)

Atripla has a score of 7 (which is not bad).

hope this is what you where looking for

Eric

PS :
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3227164/

is good reading too...

[newt]

Overview from a lay perspective of the topic in general (not a study).

http://i-base.info/ttfa/section-2/211-compartments-and-sanctuary-sites

While many studies show in some populations HIV viral load is 1 log higher in the genitals this still is probably not important (esp given the error or margin on viral load tests is 1 log), eg in gay men (v up to date this article and one of many and also shows importance of other things on localised viral load eg inflammatory infection in your gentials):

http://journals.lww.com/aidsonline/Abstract/publishahead/Highly_active_antiretroviral_therapy_does_not.98952.aspx

Also on this topic is a news item from a while ago on this topic from AIDSMEDS (or course it helps if you are on treatment and take your pills)

http://www.aidsmeds.com/articles/hiv_semen_transmission_1667_22190.shtml

This shows lower viral load in the genital tract. I include this link just to how the story is not clear cut:

http://jcm.asm.org/content/38/4/1414.full

This is a biggie for me, cos viral load relates to transmission and here low blood viral load = low/0 transmission (or thereabouts), therefore low blood viral load = low viral load elsewhere:

http://journals.lww.com/aidsonline/Fulltext/2009/07170/Sexual_transmission_of_HIV_according_to_viral_load.13.aspx

The whole blood/brain barrier penetration thing being important is unproven, in the short term yes, perhaps, but I personally think it;s the length of therapy that counts here.

- matt