转帖一篇Medhelp上关于安全套的有效性的专家回复

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confused
by slightlyworried998, Nov 22, 2009 03:35PM

Howdy docs. I am hoping that you can provide some insight into a bit of confusion i have.

I had anal sex with a fellow whose HIV status is unclear. I did ask and the guy said he was neg and only ever played safe but hadnt been tested in over a year.

Well I topped him and used a condom with KY jelly. We didnt do anything else.

So here is my confusion. I went to look up infection info on the CDC and other websites, and they seem to say that there is infection risk even when the top uses condoms (maybe because of breaks?)

When we had sex the condom didn't break or fall off. Does that mean there is still a risk for HIV in this encounter? What about other stds?

Sorry if this question seems stupid, Im trying to understand what condoms do and dont do and different web sites say different things. i just want the straight dope. Thanks for clearing this up, you guys really provide a valuable service to the community.



     医生你好。我希望你们能帮我解答一点困惑。

     我和一个不知道是否感染了艾滋病毒的男人发生了肛交。我问过他，他说他没有感染并且从来只进行安全的性行为，但他已经有一年多没有检测了。

     我戴着涂上了润滑油的安全套插入了他。我们没有做别的事。

     我的困惑就在这里。我在疾控中心和其它的网站咨询过有关感染的问题，他们好像说即使用了安全套仍然有感染的风险（也许是考虑到安全套可能会破？）。

     我们做爱的时候安全套没有破也没有脱落。这是不是意味着仍然有感染的风险？其它性病呢？

     如果这个问题看起来显得愚蠢，我抱歉。我想知道什么是安全套能做的和不能做的，而不同的网站的说法不同。我只想知道确切的事实。谢谢你们的解答，你们确实为这个社区提供了一种非常有价值的服务。


Doctor's Answer


by H. Hunter Handsfield, M.D., Nov 22, 2009 05:53PM

Welcome to the HIV forum. And congratulations on your commitment to safe sex.  If all gay men pursued sexual safety as carefully as you do, HIV would eventually disappear among gay/bi men.

And thanks for asking an important question, which provides me an opportunity to clear up a common confusion about condom effectiveness.

There are two concepts in measuring condom protection:  biological effectiveness and  "use effectiveness".  Biologically, condoms are pretty much foolproof if they don't overtly rupture.  HIV cannot pass through intact latex or polyethylene.  Correct and proper use, without breakage, is virtually 100% protective.

Unfortunately, condoms often are not "correctly and properly" used.  You also need to understand how data on condom protection are collected.  All available information depends on patient recall about whether and when condoms were used.  And human memory is fallible.  And some people overtly lie, because they are embarrassed to admit they didn't follow common sense guidelines.  Other times, condoms in fact break, sometimes without the user knowing it.  Also, often someone doesn't in fact know when s/he caught the virus and from whom, and gives wrong information on that basis.  For example, imagine someone who has a casual sexual exposure with a condom, and gets HIV -- while not knowing that his regular partner has HIV.  His history indicates apparent HIV transmission despite a condom.  And so on -- lots of uncertainty in interpreting past information about condom use and sexual safety in general.

You get the idea.  As a result of these issues, at a population level -- i.e. over thousands of people in a given community of sexually active persons at risk for HIV -- condoms probably are around 90% effective in preventing HIV.  But at a personal level, the bottom line (no pun intended) is that you can consider yourself virtually 100% protected for any particular exposure with a condom, if the condom remains intact. If you continue to combine condom use plus routine exchange of HIV information with partners, your risk for HIV will remain very low.

I hope this helps.  Best wishes, and stay safe--  HHH, MD



     欢迎来到预防艾滋病社区。祝贺你对于安全性行为的承诺。如果所有的男同性恋者都尽可能地追求安全的性行为，那么艾滋病毒最终将在同性恋和双性恋人群中消失。

    感谢你提了一个非常重要的问题，使得我有机会解答一个关于安全套的有效性的普遍的困惑。

   在安全套保护里有两个概念：生物有效性和“使用有效性”。从生物学的角度来看，如果没有明显地破裂，安全套是万无一失、十分安全的。艾滋病毒不可能穿过完整的乳胶或聚乙烯。正确和恰当地使用，无破损，是100%的保护。

    不幸的是，安全套往往并不是被“正确、恰当地”使用。你还需要了解关于安全套的安全性的信息是怎样被收集起来的。所有可用的信息依靠于对于是否和何时使用了安全套的耐心回忆。但是人类的记忆并不可靠。并且有些人公然撒谎，因为他们羞于承认他们没有遵照常识性指南。在其它时候，安全套实际上破了，有时人们却并不知道。同时，经常有人实际上不知道他是什么时候感染上的艾滋病毒，是谁传染给他的，在此基础上给出了错误的信息。例如，假如有人和一个陌生人发生了一夜情，使用了安全套，结果他患上了艾滋——但是他却并不知道他平日的伴侣有艾滋病。那么他的情况就明显不是那次的安全套的问题了。等等。在阐述过去的有关安全套的使用和性行为的安全性上，一般存在着大量的不确定因素。

   你懂我的意思吧。由于这些问题的存在，在群体的层面上——比如，在一个由超过数千人的有感染艾滋病风险的性活跃人士组成的特定社区里——安全套大概有90%的有效性。但是从个人的角度来讲，在任何一次特定的性行为中，如果你使用了安全套，并且安全套在整个过程中保持完整无缺，那么你可以认为你是100%被保护了。如果你继续使用安全套并且经常和同伴们交流有关艾滋病的信息，那么你感染艾滋病的风险一直都会非常低。

   希望以上这些能帮到你。祝福你，希望你一直安全。——HHH, MD