About the Breeder's Question (RISK OF HIV AS A TOP, 2010) (ANAL MUCOUS, ANAL FLUIDS, RECTAL SECRETIONS, 2010)


Dr. Bob,

I'm glad you clarified something about the risk for tops. You stated the CDC says the risk of an unprotected, insertive partner with a bottom known to be HIV poz is 6.5 per 10,000 exposures. You said that was a very high relative risk. Whenever I've seen those numbers before, I always thought fairly low risk. It proves I need to do my homework.

The whole risk thing is interesting to me. I know tops get infected. However, every total top I know keeps testing negative after years of bareback sex. I guess they have just been lucky. It seems everyone I know who is poz got it by bottoming. If the risk is that high for total tops, I would think there would be more than one million HIVers in the U.S. I always thought straight guys got it because vaginal fluid carried HIV better than the anus.

I know you've probably talked about this before, but I'm always curious--

Would you mind explaining the difference between putting your penis in someone's mouth and their butt? What is happening in the butt? Does there have to be blood involved in the butt to infect the top? Or, is HIV just present in the anus in fluid? That fluid/blood would have to make its way up the uretha or a sore on the penis? If the top ejaculated, would that force everything out?

My negative partner keeps telling me he could top, because it is a very low risk. I don't even like the idea of letting him perform oral on me.



The CDC statistical estimate of risk provides information about relative risk rather than actual risk applicable to a specific encounter. Unprotected insertive anal sex with a poz partner (6.5 per 10,000 exposures) is, for example, much riskier than unprotected receptive oral sex with a poz partner (1 per 10,000 exposures), but not as risky as unprotected receptive anal sex with a poz partner (50 per 10,000 exposures). There are many confounding variables for a specific encounter, both viral (viral strain, viral load, etc.) and host (immune integrity, concurrent illness, trauma during sex, etc.).

As for knowing total tops who keep testing negative, even after barebacking, yes, they are lucky. Also, would you really expect HIVers who become infected from voluntarily putting themselves at risk (when they obviously should have known better) to broadcast the news they lost their game of sexual Russian Roulette? I can assure you after caring for a great many HIVers I've personally known many total tops who became infected. (See below for an example.)

Next, you want me to explain the difference between putting your penis in someone's mouth and in his butt? Dude, I've known guys who were a bit confused about anatomy, like not knowing which side their liver was on, but not knowing the difference between one's mouth and butt???? Now that's a bit worrisome!

As for HIV risk, saliva does contain components that inhibit HIV. Also, there is much less risk of local trauma from oral as compared to anal sex. Blood does not have to be present for a top to be infected during anal sex. (See below.) The urethra is lined with a mucous membrane. HIV can be absorbed across a mucous membrane without cuts, sores or trauma. Ejaculation does not "force everything out," as infected fluids merely need to come into contact with the mucous membrane; they don't have to travel all the way up the nine-plus inches (if you're Italian) of your Mr. Happy.

Regarding your negative top gun, I'd suggest you have him read the information on this site, in its archives and on the related links. We have an entire chapter on magnetic couples in the archives.

Dr. Bob

Re: risk of HIV as a TOP May 15, 2010

I've always been an exclusive top, a medical professional who couldn't believe you could get HIV from just topping. I figured the worst that could happen would be the usual STD's and I would self medicate

Well here I am HIV positive

Don't top with out protection. I've known others just like me.

Response from Dr. Frascino

Hello Medical Professional,

Thank-you for your honesty and taking the time to write in. I'm confident your testimonial will save lives. See below.

I'm here if you ever need me. Let's get through this together as positively charged medical professionals dedicated to helping others stay HIV free.

Be well.

Dr. Bob

HIV transmission thru urethra Feb 16, 2010

Hi there,

about 4 weeks ago I had some contact with the anal fluids of another guy. I was going to top him, but decided I wouldn't. I just fingered him and sort of penetrated him without going all the way in. I doubt this guy is HIV+ but there's always that chance. A few weeks later, I got a urinary tract infection - the whole works, diarrhea and everything, and took antibiotics which cleared it up. I was really startled to learn that HIV can enter through the urethra. But it makes no sense to me how anal "fluids" (whatever they might be...sweat or just ordinary liquid secretions?) could have a sufficiently high concentration of HIV to infect someone? It seems like nowadays it's just better to avoid sex altogether...everyone just seems to be a germ farm nowadays. Last year I had a really nice session of kissing with a guy, which resulted in a 6 week long upper respiratory infection (which he came down with too, but he didn't know it while we were making out.) Anyhow, any light you can shed on my urethral contact with anal fluid would be appreciated. Thanks for your time, -Andy

Response from Dr. Frascino

Hello Andy,

The rectum is lined by a mucous membrane. Mucous membranes secrete mucous ("anal fluid"). Your nose and mouth also are lined with mucous membranes and they too are always "wet," right? HIV can permeate across mucous membranes (but not intact skin). As it turns out, the urethra is also lined with a mucous membrane. Consequently, if your unprotected tallywhacker's urethra comes into contact with infected anal fluid, HIV can be absorbed across the mucous membrane and result in HIV transmission/acquisition.

Why consider give up sex? Isn't it easier just to put a latex condom on your big bopper?

Dr. Bob

insertive issues (Rectal secretions from men who have sex with men contain more HIV than blood or semen) (ANAL MUCOUS, RECTAL SECRETIONS, 2010) Mar 30, 2010

I have a hard time believing as an exclusive TOP that I contracted this virus through anal juice sneaking up my urethra while servicing a bottom. I'll bet one way a top more likely gets infected and probably what happened to me was topping a guy who had just had sex with someone else (yes there are actually places where that might occurr!!) and had someone else's infected semen still in his rectum, and that's what snuck up my urethra, semen having a much higher viral load than anal secretions. Theoretically, therefore I could have been infected by some one I literally did not have sex with and the bottom might not have even been poz. What do you think? I'll bet this happens more often than believed.

Response from Dr. Frascino


What you choose to believe or "have a hard time believing" is, of course, totally up to you. However, it really doesn't change scientific fact. Do I think your hypothesis is correct? Nope. Sorry, Charlie, I don't. You can read a great deal about the biology of HIV transmission in the archives and related links if you so desire.

Dr. Bob

Hello Dr. Frascino, I was wondering if you could actually explain this post considering I am currently on PEP for having sex with a HIV negative bottom but who I think had an unknown person's ejaculate in his anus when I topped him. If this doesnt seem like a reasonable route for transmission, I will most likely stop the PEP, considering the bottom is negative. Could you please shed some light..thank you for your help.

Response from Dr. Frascino


Dude, it really doesn't matter what you personally believe or what wild notions you might concoct about your cock and acquisition of HIV. The reality of your situation is that you became infected with HIV because you unwisely decided to have unsafe sex with your Brokeback Mountain buddy. Top-gun or bottom-boy unprotected anal sex is risky business. I should also point out several studies have found very high levels of HIV in rectal mucosa secretions (anal mucous). (See below.) Heads up top guys! Shield your rocket or keep it in your pocket!

Dr. Bob

Rectal secretions from men who have sex with men contain more HIV than blood or semen Chris Gadd, Wednesday, June 16, 2004 Levels of HIV RNA in rectal mucosa secretions from men who have sex with men (MSM) are higher than those in blood and semen, according to a study presented in the July 1st edition of The Journal of Infectious Diseases. The results suggest that unprotected insertive anal intercourse may involve exposure to higher levels of free virus than previously believed, even where the receptive partner's plasma viral load is undetectable on HAART.

In contrast to previous studies, which have examined HIV levels in rectal biopsies (tissue samples) or swabs from the anus in men with suppressed viral loads, this study looked at secretions from the rectum in a group of men with varying degrees of viral suppression and antiretroviral drug exposure.

"HIV RNA was often found at high levels in rectal secretions, even in men receiving antiretroviral therapy, and paired HIV RNA levels in rectal secretions were greater than those in either the blood or seminal plasma among HIV-infected MSM," state the authors. Furthermore, "antiretroviral therapy had a greater direct effect on levels of HIV in seminal plasma than in rectal secretions."

The investigators recruited 64 HIV-positive MSM from sexually transmitted disease clinics in Seattle, USA, and Lima, Peru between December 1999 and January 2001. Twenty-seven (42%) of the men had been on a stable antiretroviral regimen for at least 30 days, and the remainder were drug-naive.

HIV viral loads were measured two to three times over four weeks in swabs taken from the rectum, and in the blood and semen. Because the samples were diluted at different ratios, the lower limit of detection was not equal in the three samples (rectal secretions: 8000 copies/ml; blood: 400 copies/ml; semen: 800 copies/ml). However, the authors used a mathematical correction to estimate the distribution of viral loads in samples below the limits of detection.

Overall, HIV viral loads were higher in rectal secretions (median 91,200 copies/ml) than in blood (median 17,400 copies/ml; p < 0.05) or semen (median 3550 copies/ml; p < 0.05). Nevertheless, HIV viral loads in the blood were correlated with those in the rectum (p < 0.001) and the semen (p < 0.001).

A similar pattern of viral loads was observed in the men who were taking antiretroviral therapy. Rectal secretions contained a median of 3980 copies/ml, compared with 200 copies/ml in blood (p < 0.05) and 1000 copies/ml in semen (p < 0.05). Ten (37%) of 27 rectal samples from these men had detectable viral loads, nine (35%) of 26 blood samples, and eleven (55%) of 20 semen samples, a much higher level than observed in most other studies, the authors note.

In the men who were not taking antiretroviral therapy, HIV viral loads differed significantly among all three samples, with rectal secretions containing the highest viral loads (median 316,000 copies/ml), compared with a median of 63,100 copies/ml in the blood and 12,600 copies/ml in semen (p < 0.05 for all comparisons). These men also had higher rates of detectable viral loads in the rectum (35 [95%] of 37 samples; p < 0.05), and blood (37 [100%] samples; p < 0.05), but not in the semen (28 [78%] of 36 samples; p = 0.08).

Using mixed-effects model analysis without controlling for blood viral loads, the authors demonstrated that the use of antiretroviral therapy caused a 1.3-log10 reduction in rectal viral loads (p < 0.001) and a 1.4-log10 reduction in seminal viral loads (p < 0.001). Lower CD4 cell counts were also associated with higher viral loads in both samples (p = 0.03 and 0.004 respectively).

When blood viral loads were included in the model, the authors found that a one-log10 reduction in blood viral loads caused a 0.5-log10 reduction in both rectal and seminal viral loads (p = 0.006 and 0.02 respectively). However, use of HAART was found to reduce viral loads in the semen, but not rectal secretions (p = 0.003 and 0.5 respectively).

This leads the authors to suggest that the effect of HAART on rectal viral load occurs as a result of viral load reductions in the blood. In contrast, antiretrovirals may affect viral levels in the semen directly. This "may be due to differential levels of antiretroviral drugs or to anatomic and immunologic differences in the male genital tract versus rectal mucosa."


Zuckerman R A et al. Higher concentrations of HIV RNA in rectal mucosa secretions than in blood and seminal plasma, among men who have sex with men, independent of antiretroviral therapy. J Infect Dis 189: 156-161, 2004.