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Comment by jxramos | Hacker News Reader

I always felt like the only way you can eliminate the spread of a highly adaptive std is to develop a low barrier on-the-spot test administered just before intercourse at the latest or some point reasonably earlier in a date or whatever. This would still fail under the dormancy period viruses assume but it should improve the odds I'd imagine for those connected in one way or another to promiscuous sexual networks.

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That assumes a degree of agency in your ability to refuse sex that is not necessarily the case in many high prevalence countries.

It's better to protect one party than neither party...

1. There is no silver bullet to "eliminate the spread of highly adaptive std"

2. Condoms are very effective and can be used in this type of situation.

> 2. Condoms are very effective and can be used in this type of situation.

Availability of PrEP coincides with a drop in condom usage:

https://www.theguardian.com/society/2018/jun/06/rapid-rise-i...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5640310/

A test exists. It's good but not perfect. If you have the disease it will return positive 99% of the time. If you do not have the disease it will return positive about 1% of the time. About 0.1% of the population has the disease. You take the test. It returns positive.

What are the chances you have the disease?

People on HN may be able to work this out, but I guarantee that many people (including doctors and nurses) can't.

See Gerd Gigerenzer's work on this in Reckoning With Risk or Risk Savvy.

We can re-word this to make it easier.

1000 people take a test. 1 of them has a disease, and the test will probably return positive for that person. 999 of them do not have the disease, and the test will return positive for about 9 of them.

That 0.1% includes newborns, the distribution of hiv is definitely not uniform. What are the chances if the person in question is a gay man that uses the test before unprotected receptive anal sex with newly met strangers?

But that scenario makes the test pointless: there are a wide range of things to be prevented and safer sex is a better solution than testing.

That’s sort of what porn industry does with HIV RNA TMA test. I suspect it’s quite effective.

It still has a multiple week delay before it tests positive...

HIV can remain undetectable for up to six months.

Porn industry uses an interesting trick:

since all porn talent on all non-underground shoots is supposed to only engage in sex with others (on and off the set) who tested negative and since the new talent has to test negative first time weeks before the talent enters the pool even the look back tests are very effective.

That's not a bad idea, but how does liability play out on a defective test, or a test used in a manner other than directed?

Would you bet the rest of your life on a casual test like that?

>Would you bet the rest of your life on a casual test like that?

On an individual level, this doesn't guarantee much, but on a population level this could provide a huge benefit. You yourself might not feel confident based on the test, but it would likely severely limit the spread of STDs (as long as treatment is available and accessible).

Even if treatment isn't available.

The main benifit of a bed-side test isn't that it informs the person who is infected. It is that it informs the person who is not infected.

Currently, most people who ask about STD status just take their partners word. Maybe a particuarly paranoid person will ask to see actual lab results, which could reasonably be months or years old at best (how often do you expect people to get tested?) or maliciously forged at worst (hopefully rare enough to be irrelevant at the population level).

With a bedside test, you get up to date information (subject to the quality of the test) on if you are about to get exposed, and can avoid the exposure if necessary.

There is still the cultural issue of needing to test your partner before an interaction, would might come across as prohibitively offensive.

Maybe?

HIV transmission is not so easy; last I checked, the rough odds of transmission from a single act of unprotected vaginal sex with a HIV+ partner was around 1 in 500.

If the test is 99% accurate, and your partner isn't in an obvious high risk group, it may push the odds into "less risky than other behaviors you commonly accept" territory.

For point of reference, condom use only decreases the risk by a factor of 10. Possibly less: https://www.catie.ca/en/fact-sheets/prevention/condoms

What is your source for the 1 in 500? The numbers I found on the same website indicate an even smaller risk https://www.catie.ca/en/pif/summer-2012/putting-number-it-ri... However, "As you can imagine, accurately tracking the number of times a person is exposed to HIV is very difficult".

I don't recall; the numbers on Catie (~1 in 1250) are more modern and certainly a better estimate.

Either way, you only have to add a few more digits of risk mitigation and you're more likely to die in a car accident. A test that had even a 1% false negative rate would cover most of that ground.

In developed countries most HIV transmission is due to anal sex between men who have sex with men, where the odds of transmission per single act are more like 1 in 30. The transmission is much more heterosexual in Africa however, where most of this resistance is happening. [1] I'm kind of confused about the sexual practices that could cause this to happen, but I'm sure prostitution and rape (which increases transmission odds due to trauma) are involved.

[1] https://www.healthline.com/health/hiv-aids/rate-global-diagn...

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