Immunology (including AIDS)/inquiry


I've heard that GAY men cannot get HIV if cum is swallowed during oral this true?

It doesn't matter if you are gay or not, first of all.  It's the behavior.   

While there are a lot of sites on the internet who will tell you this is true, no responsible government agency would say this.   The people on this site typically with cite a study (or two) when it didn't happen.   However, there have been studies that it did happen.  And this is easy to understand.   If something doesn't happen often or requires special circumstances then in a specific study it may not happen.  Whereas those things might in a separate study.   So these people simply don't know their statistics.

Consider this as an example, you do a study with a 100 people.  Each time there is a thunderstorm you ask them to stand out in the rain with an umbrella.   After some time you stop your study and you see that no one in the study got hit by lightning.  So you erroneously conclude that people cannot be hit by lightning.   Would you believe that?

Let me give you another example, the Conference for Retroviral Infectious disease is reporting on a study of men who have sex with men.  It's been going on for about 6+ months.  There are no rules for using a condom or not.  No use for drugs.  Simple one person in the study is HIV+ and the other is HIV-.    So far, not one of the HIV- men has contracted HIV.   Would you believe that HIV cannot be transmitted?

So you have to do  more home work.   And what is that?

First you have to determine if it is even possible.  The answer is "Yes".    Animals have been infected with HIV by placing HIV in the mouth.  So this rules out the theory that saliva will always kill it.   Animals have saliva also.

Second, you have to look at reports.  While they cannot be accepted on their own, you have to include them in your determination.   Just like you have to include reports of people who are hit by lightning world-wide in your determination.   There are many people who insist that their only exposure was oral sex.   

You can read this woman's story:

And while this is anecdotal, Governments such as the UK government did a 5-year study and determined that it happened at least 40 times.  It's a small number in part because it doesn't' happen often and because in these limited cases they were able to very clearly rule out any other route of transmission.   Based on this they have stated that from a single exposure the risk is about 1/5000 or less.  Other governments have said it's 1/10000.   But all government bodies throughout the world have accepted it as a possibility, even if it's a low probability.    And low probability events do occur.

So in short, we conclude that it can happen from animal models (i.e. the assertion that saliva will always kill is not true),  we consider the mix results of studies which can be explained by assuming a low probability, and we have to consider epidemiological studies conducted by reportable government bodies.   After this, you'll see that the medical experts on the same sites (e.g. and others) that lay people on these sites will say "no risk," "can't happen" etc, will tell you that its possible but it's a low risk.   The problem is that these lay people take the phrase "low risk" and jump to "no risk" and "not possible" because they are not familiar with animal models show that it can happen even in the presence of saliva.

In a particular situation, a major website had an MD who they used as their source for "no risk" comments.  After talking to him personally and showing him the epidemiological studies and the animal model results, he finally admitted it might happen.   Unfortunately, while the MD has changed his mind, the lay people on the site continue to insist it's no risk.

Also keep in mind that people who operate some of these sites who insist HIV cannot be transmitted orally will delete the accounts of anyone who says otherwise.  So you will not always hear the complete story.   They will not only delete the account they will delete all messages of this sort.

Having said this let me be clear,  there have been cases where a person giving oral sex to a man has contracted HIV.   There has not been based on my research a case where the person receiving oral sex who has gotten HIV.   But the common view is that getting HIV by giving oral sex to a man is about 1/2500 - 1/10000 (depending on which government body) and 1/20000 for receiving oral sex.

Feel free to write back.  

Immunology (including AIDS)

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sam williams


I'm an expert in HIV/AIDS.


Mostly in testing and prevention. I have some limited knowledge of post HIV infection testing protocols e.g. CD4, CD8, etc. I also have some knowledge about HIF drugs. But most of that comes from my knowledge of PEP and PrEP. Where I'm different from other websites, and believe this is important, is that i admit the possibility of HIV via oral transmissions. All medical experts agree with this as a possibility. There are animal model studies that show this is possible. However, laymen who answer questions at sites like the,,, etc will insist that oral sex carries zero risk. Ironically, when medical professionals answer questions on these sites, they all admit that oral sex is a risk. I stick to what medical professionals and government bodies say on this and other HIV information. My other area of expertise is PEP (HIV drugs to prevent HIV). And PrEP.


I'm a layperson. I have only training through volunteer work. I also do extensive reading on the subject. I read source throughout the world, since I find that the CDC and FDA are woefully behind. For example, 4th generation testing has been available in Europe for 15 years. FDA approved it 5 years ago. The CDC only made a favorable statement about it last year. In my own study of this, I find that <1% of MDs in the US are using 4th generation testing.

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