Study: Those on drugs 92 percent less likely to infect partner

[DanKenny]

Meds sharply cut HIV transmission risk // Study: Those on drugs 92 percent less likely to infect partner


http://www.msnbc.msn.com/id/37367084/ns/health-aids/

[WhySoUnfair]

Meds sharply cut HIV transmission risk // Study: Those on drugs 92 percent less likely to infect partner


http://www.msnbc.msn.com/id/37367084/ns/health-aids/

When it happens, it's either 0% or 100%!!

[Hellraiser]

When it happens, it's either 0% or 100%!!

Debbie Downer Strikes again

[Boze]

When it happens, it's either 0% or 100%!!

I actually bothered to read the story and cut out the relevant bit:

"The team analyzed 3,400 couples from seven African countries. In each couple, only one partner was positive for the human immunodeficiency virus, or HIV, which causes AIDS. The team tested couples because they were easier to keep track of.
All of the couples were given counseling on HIV prevention methods, and some were offered HIV drugs when they became available.
During the study, 349 HIV-infected partners were started on HIV drugs. Of the 103 people who became infected during the study, only one caught the virus after the infected partner started taking the drugs.
Donnell said the drugs cut the concentration of HIV in the blood to very low levels, which may make people less infectious. In people who took the drugs, the virus was suppressed to very low levels in nearly 70 percent of cases."

So - 1 (one) person was infected (out of 103 - not clear) and only 70% of cases reached UD. So I have no idea where 92% comes from. Most likely that one person's partner was not UD (since 30% of the group was not UD). So i'd rephrase the headline - 100% reduction in transmission for Undetectable Viral Load.

[Hellraiser]

You misunderstand...


3400 couples where one partner is hiv positive.

103 of the negative partners became infected.

349 of the positive partners were STARTED on drugs during the study.

Of the 103 infections only 1 person was infected after their partner started taking drugs.

70% of the people on ARVs (no idea how many of the total couples were on drugs before the study began) had an Undetectable viral load.

There are too many numbers and unknowns for me to figure out which hat they pulled the 92% reduction rate out of.  There will most likely never be a 100% number given for infectious of anyone who is HIV+ as in the science community there is usually at least a little wiggle room given for doubt.  It does bode well though that perhaps if a link can be made between meds and lowered transmission the meds will be more widely available at a reasonable cost.

[Boze]

349 of the positive partners were STARTED on drugs during the study.

Of the 103 infections only 1 person was infected after their partner started taking drugs.

So sounds like 1 transmission out of 349 couples on ARV?

I remember Dr. Gallant stating that there has not been a known case of UD person transmitting (http://www.google.co.uk/search?sourceid=chrome&ie=UTF-8&q=dr.+gallant+ud+infect). So this 92% headline actually bothers me as it implies an 8% risk.

[Hellraiser]

So sounds like 1 transmission out of 349 couples on ARV?

I remember Dr. Gallant stating that there has not been a known case of UD person transmitting (http://www.google.co.uk/search?sourceid=chrome&ie=UTF-8&q=dr.+gallant+ud+infect). So this 92% headline actually bothers me as it implies an 8% risk.

I'm guessing it's the number of transmissions that occured amongst the 3400 who were on ARVs is the 8% number, there is no mention of viral load as a mitigating circumstance though aside from the 70% number.  1 out of 349 is lower than 1% though obviously.

[Boze]

I'm guessing it's the number of transmissions that occured amongst the 3400 who were on ARVs is the 8% number, there is no mention of viral load as a mitigating circumstance though aside from the 70% number.  1 out of 349 is lower than 1% though obviously.

So retarded journalism basically.

[Hellraiser]

So retarded journalism basically.

They are being very very vague with the details, I'm not certain if it's on purpose or they just felt they gave us enough information.

[Boze]

They are being very very vague with the details, I'm not certain if it's on purpose or they just felt they gave us enough information.

True - but even going by the details provided 8% makes no sense.

[Hellraiser]

True - but even going by the details provided 8% makes no sense.

8% while one partner was utilizing ARVs not while one partner was on ARVs and undetectable.

[Boze]

8% while one partner was utilizing ARVs not while one partner was on ARVs and undetectable.

What is the nominator / denominator to get 8%?

I understood that "Of the 103 infections only 1 person was infected after their partner started taking drugs."

[Hellraiser]

What is the nominator / denominator to get 8%?

I understood that "Of the 103 infections only 1 person was infected after their partner started taking drugs."

They do not tell us how many of the epople in the study were on ARVs only how many began ARVs once the study commenced. So there may have been a number of these couples on ARVs before the study began or none at all.

[Boze]

They do not tell us how many of the epople in the study were on ARVs only how many began ARVs once the study commenced. So there may have been a number of these couples on ARVs before the study began or none at all.

Ahh, I see, thank you.

It gives me great pleasure to find myself in agreement (on unrelated topics) with someone who sees things more clearly than I do

[Assurbanipal]

Just looking at the numbers above

3400 - 349 = 3051 , presumably the number not on ARV's

103 partner infections, 1 of which is was infected by a partner on ARV's

102/3051 = 3.34% of partners infected by those not on ARV's

1/349 = 0.29% of partners infected by those on ARV's

.29/3.34 = 8.5% hence only 8.5% as infectious as those not on ARV's -- pretty close to a 92% reduction in infectiousness

One assumes (hopes) that the numbers are weighted by duration on meds as well...


*Edit -- accidentally posted while still typing

[Boze]

Excellent work, Assur!

But then it raises the question - did non-ARV couples use condoms?

"All of the couples were given counseling on HIV prevention methods, and some were offered HIV drugs when they became available." It sounds like they had to tell people to use protection.

However once on meds people might stop using condoms? The reason I am suspicious is that 3.4% transmission risk sounds incredibly low.

[Assurbanipal]

Someone who read the study said:

All of the couples were given counseling on HIV prevention methods,...

 

[Cerrid]

Of the 103 people who became infected during the study, only one caught the virus after the infected partner started taking the drugs.

That's a pretty good result on the basis that they apparently did not take into account the VL, the effectiveness of the drugs, the compliance, the presence or absence of other STDs, the sexual activity with the same or other partners, or the positioning of the partners - all factors which play a role in the transmittability.

[tednlou2]

This is why I love you guys.  Most of you are able to read this stuff and make sense of it.  I read many of these studies and get a headache.  I have to read, re-read, and read again.  Even then, I often can't make sense of it.  I think people who are good and math are able to read these things better.  I sucked at math.