4 ms·

> and results published Wednesday show it worked nearly as well in men. So not as well? Is there a biological reason for this? Also, is it typical to do such

> and results published Wednesday show it worked nearly as well in men. So not as well? Is there a biological reason for this? Also, is it typical to do such studies on single genders rather than on a mix of humans?

a_t48 2y ago
Receptive PIV sex has 2% transmission rate, PIA is 20%. Cis men don't have a vagina, so...
- t-writescode 2y ago
  There's also a chance that the countries they were able to / encouraged to test in are quite hostile to LGBTQ+ people
  - saagarjha 2y ago
    This is mentioned in the article.
- bobthepanda 2y ago
  To further elaborate, the anal mucous membrane is thinner than that of the vagina, so it’s easier for HIV to transmit that way.
- perching_aix 2y ago
  could you undo the abbreviations please?
  - dhaugshs 2y ago
    Penis in vagina. It's a specification. It's like "birthing parent", to be clear what hardware is being used. Given that HIV infection rates are very variable (over an order of magnitude, sometimes two) by subpopulation, clarifications detailing what hardware is doing what are very necessary.
    - IshKebab 2y ago
      We already have words for that: anal/vaginal sex.
      - a_t48 2y ago
        Yeah you’re right, I’m not sure why I wrote it that way.
  - deleted 2y ago
    [deleted]
- ProfessorLayton 2y ago
  Your numbers are way, way off [1]. Receptive vaginal sex: 0.08% (1 transmission per 1,250 exposures) Insertive vaginal sex: 0.04% (1 transmission per 2,500 exposures) Receptive anal sex: 1.4% (1 transmission per 71 exposures.) Insertive anal sex: 0.11% (1 transmission per 909 exposures) [1] https://stanfordhealthcare.org/medical-conditions/sexual-and-reproductive-health/hiv-aids/causes/risk-of-exposure.html https://stanfordhealthcare.org/medical-conditions/sexual-and...
  - a_t48 2y ago
    Ah, I didn't read carefully - https://stanfordhealthcare.org/medical-conditions/sexual-and-reproductive-health/hiv-aids/causes/risk-of-exposure.html#:~:text=Therefore%2C%20unprotected%20sex%20with%20an,exposures)%20for%20receptive%20anal%20sex https://stanfordhealthcare.org/medical-conditions/sexual-and.... is my source, this was for acute infections. Regardless, it's still more than an order of magnitude of difference. Sadly too late to edit.
Fomite 2y ago
A few reasons: - Women and girls make up the majority of HIV cases, especially in the developing world - If you're estimating the effect in both men and women, you're reducing your power to detect an effect in either group. If you have a limited budget, it's going to be hard to recruit, etc., you may well be better off powering your study for the group you think is going to be the most impactful, then going back. We saw this with the HPV vaccine - getting it going in the highest impact groups, and then going back later - Preventing HIV in women also prevents maternal to child transmission - "Men with HIV" are actually two different groups - men who have sex exclusively with women, and men who have sex with men. You then also need to power your study for both sub-groups.
- mike_hearn 2y ago
  That's inaccurate. The vast majority of all cases are in men. For instance in America only 22% of HIV+ people are women. Our World In Data has a map that shows this visually: https://ourworldindata.org/hiv-aids https://ourworldindata.org/hiv-aids The only place this isn't true is sub-Saharan Africa. As there's no biological explanation for that discrepancy it's been hypothesized that it's because in Africa a lot of reported HIV cases are fraudulent, due to the large amount of AIDS/women specific foreign aid money and weak auditing standards.
  - foldr 2y ago
    It's not inaccurate. More than half of the people currently living with HIV worldwide are women: https://www.unaids.org/en/resources/infographics/girls-and-women-living-with-HIV#:~:text=Girls%20and%20women%20make%20up,the%20centre%20of%20the%20response https://www.unaids.org/en/resources/infographics/girls-and-w.... https://www.hiv.gov/hiv-basics/overview/data-and-trends/global-statistics https://www.hiv.gov/hiv-basics/overview/data-and-trends/glob...
    - mike_hearn 2y ago
      The phrasing "majority of all cases, especially in the developing world" implies that it's true everywhere. Even putting that aside, it's only the bizarre situation in Africa makes the statement technically true. If we interpret it in the way it was meant to be interpreted then the statement isn't really true because everywhere that has reliable data shows the opposite: men get it the most.
9x39 2y ago
HIV has heavily…gendered outcomes. Others have mentioned infection rates, there’s also sheer exposure rates to consider. https://www.cdc.gov/hiv-data/nhss/estimated-hiv-incidence-and-prevalence.html https://www.cdc.gov/hiv-data/nhss/estimated-hiv-incidence-an...
- bobthepanda 2y ago
  This varies between countries. In South Africa, the country with the largest HIV positive population, women have double the HIV incidence of men. https://sph.brown.edu/news/2024-11-07/south-africa-hiv-obstetric-care https://sph.brown.edu/news/2024-11-07/south-africa-hiv-obste...
  - 9x39 2y ago
    That’s interesting that the gendering is reversed in Africa. Why do you think that is? The linked article didn’t try to explain it. The OP article covered Mexico which remains closer to the US in outcomes being heavily male-gendered. https://www.unaids.org/en/regionscountries/countries/mexico https://www.unaids.org/en/regionscountries/countries/mexico https://www.statista.com/statistics/941203/distribution-individuals-registered-hiv-mexico-gender/ https://www.statista.com/statistics/941203/distribution-indi...
    - bobthepanda 2y ago
      my understanding is that * condom use is much lower in sub-Saharan Africa * polygamy, specifically a man with multiple wives, is also more common in sub-Saharan Africa
ChrisRR 2y ago
When you're trying to limit the variables on a study, yes. HIV reception between men and women has many differences so it can be better to limit your study and get twice as much data
astura 2y ago
The receptive partner in sexual activity is at much higher risk of infection than the penetrating partner.
- hackernewds 2y ago
  Soooo we should've seen the opposite outcome given that fact?
BrouteMinou 2y ago
[flagged]

a_t48 2y ago

Receptive PIV sex has 2% transmission rate, PIA is 20%. Cis men don't have a vagina, so...

t-writescode 2y ago
There's also a chance that the countries they were able to / encouraged to test in are quite hostile to LGBTQ+ people
- saagarjha 2y ago
  This is mentioned in the article.
bobthepanda 2y ago
To further elaborate, the anal mucous membrane is thinner than that of the vagina, so it’s easier for HIV to transmit that way.
perching_aix 2y ago
could you undo the abbreviations please?
- dhaugshs 2y ago
  Penis in vagina. It's a specification. It's like "birthing parent", to be clear what hardware is being used. Given that HIV infection rates are very variable (over an order of magnitude, sometimes two) by subpopulation, clarifications detailing what hardware is doing what are very necessary.
  - IshKebab 2y ago
    We already have words for that: anal/vaginal sex.
    - a_t48 2y ago
      Yeah you’re right, I’m not sure why I wrote it that way.
- deleted 2y ago
  [deleted]
ProfessorLayton 2y ago
Your numbers are way, way off [1]. Receptive vaginal sex: 0.08% (1 transmission per 1,250 exposures) Insertive vaginal sex: 0.04% (1 transmission per 2,500 exposures) Receptive anal sex: 1.4% (1 transmission per 71 exposures.) Insertive anal sex: 0.11% (1 transmission per 909 exposures) [1] https://stanfordhealthcare.org/medical-conditions/sexual-and-reproductive-health/hiv-aids/causes/risk-of-exposure.html https://stanfordhealthcare.org/medical-conditions/sexual-and...
- a_t48 2y ago
  Ah, I didn't read carefully - https://stanfordhealthcare.org/medical-conditions/sexual-and-reproductive-health/hiv-aids/causes/risk-of-exposure.html#:~:text=Therefore%2C%20unprotected%20sex%20with%20an,exposures)%20for%20receptive%20anal%20sex https://stanfordhealthcare.org/medical-conditions/sexual-and.... is my source, this was for acute infections. Regardless, it's still more than an order of magnitude of difference. Sadly too late to edit.

Fomite 2y ago

A few reasons: - Women and girls make up the majority of HIV cases, especially in the developing world - If you're estimating the effect in both men and women, you're reducing your power to detect an effect in either group. If you have a limited budget, it's going to be hard to recruit, etc., you may well be better off powering your study for the group you think is going to be the most impactful, then going back. We saw this with the HPV vaccine - getting it going in the highest impact groups, and then going back later - Preventing HIV in women also prevents maternal to child transmission - "Men with HIV" are actually two different groups - men who have sex exclusively with women, and men who have sex with men. You then also need to power your study for both sub-groups.

mike_hearn 2y ago
That's inaccurate. The vast majority of all cases are in men. For instance in America only 22% of HIV+ people are women. Our World In Data has a map that shows this visually: https://ourworldindata.org/hiv-aids https://ourworldindata.org/hiv-aids The only place this isn't true is sub-Saharan Africa. As there's no biological explanation for that discrepancy it's been hypothesized that it's because in Africa a lot of reported HIV cases are fraudulent, due to the large amount of AIDS/women specific foreign aid money and weak auditing standards.
- foldr 2y ago
  It's not inaccurate. More than half of the people currently living with HIV worldwide are women: https://www.unaids.org/en/resources/infographics/girls-and-women-living-with-HIV#:~:text=Girls%20and%20women%20make%20up,the%20centre%20of%20the%20response https://www.unaids.org/en/resources/infographics/girls-and-w.... https://www.hiv.gov/hiv-basics/overview/data-and-trends/global-statistics https://www.hiv.gov/hiv-basics/overview/data-and-trends/glob...
  - mike_hearn 2y ago
    The phrasing "majority of all cases, especially in the developing world" implies that it's true everywhere. Even putting that aside, it's only the bizarre situation in Africa makes the statement technically true. If we interpret it in the way it was meant to be interpreted then the statement isn't really true because everywhere that has reliable data shows the opposite: men get it the most.

9x39 2y ago

HIV has heavily…gendered outcomes. Others have mentioned infection rates, there’s also sheer exposure rates to consider. https://www.cdc.gov/hiv-data/nhss/estimated-hiv-incidence-and-prevalence.html https://www.cdc.gov/hiv-data/nhss/estimated-hiv-incidence-an...

bobthepanda 2y ago
This varies between countries. In South Africa, the country with the largest HIV positive population, women have double the HIV incidence of men. https://sph.brown.edu/news/2024-11-07/south-africa-hiv-obstetric-care https://sph.brown.edu/news/2024-11-07/south-africa-hiv-obste...
- 9x39 2y ago
  That’s interesting that the gendering is reversed in Africa. Why do you think that is? The linked article didn’t try to explain it. The OP article covered Mexico which remains closer to the US in outcomes being heavily male-gendered. https://www.unaids.org/en/regionscountries/countries/mexico https://www.unaids.org/en/regionscountries/countries/mexico https://www.statista.com/statistics/941203/distribution-individuals-registered-hiv-mexico-gender/ https://www.statista.com/statistics/941203/distribution-indi...
  - bobthepanda 2y ago
    my understanding is that * condom use is much lower in sub-Saharan Africa * polygamy, specifically a man with multiple wives, is also more common in sub-Saharan Africa

ChrisRR 2y ago

When you're trying to limit the variables on a study, yes. HIV reception between men and women has many differences so it can be better to limit your study and get twice as much data

astura 2y ago

The receptive partner in sexual activity is at much higher risk of infection than the penetrating partner.

hackernewds 2y ago
Soooo we should've seen the opposite outcome given that fact?

BrouteMinou 2y ago

[flagged]