HIV Risk Without Ejaculation During Sex

Evaluating the Presence of HIV in Pre-Seminal Fluid

Stack of multi-colored condoms
Stack of multi-colored condoms. Getty Images/Rafe Swan/Cultura

Determining your risk of getting HIV from different sexual behaviors is always a tricky subject. In evaluating your risk, you tend to weigh and pros and cons as to which activities might be safer than others. At times, this can put you at higher rather than lower risk simply because "common sense" assumptions are not often right.

One such assumption is that a person can largely ​HIV if their partner does not ejaculate.

And while it may seem reasonable given that less semen = less virus, does the theory really hold up in practice?

Breaking Down the Facts HIV in Pre-Seminal Fluid

The simple fact is that HIV present in both a male's semen and pre-seminal fluid (also known as pre-ejaculatory fluid or "pre-cum"). While the volume of HIV in pre-seminal fluids is inherently lower, that number can change significantly if a person is untreated. By and large, a person with untreated HIV will have more active virus circulating the blood and other body fluids (as measured by the HIV viral load.)

The same applies to a man who may not be taking his HIV medications correctly and is unable to achieve an undetectable viral load. Moreover, the presence of a coexisting sexually transmitted infection (STI) and even some urinary tract infection can increase a process called HIV shedding where the infection draws more HIV to the male genital tract and, by default, to the man's semen.

Similarly, the amount of pre-seminal fluid can vary from person to person. Pre-seminal fluid is released from a male's urethra (the opening in a male's penis) during sexual arousal and before ejaculation. A male can release up to 4mL of this pre-seminal fluid (a little less than one teaspoon). The longer the sexual activity, the more pre-ejaculate a man is likely to have.

Where is HIV Present: In the Sperm or Seminal Fluid?

The assumption that pre-seminal fluid is not infectious as seminal ejaculate is depending one of two big assumptions:

  1. that HIV is predominant in sperm and not so much in the seminal fluid itself
  2. that there is a certain volume of seminal fluid by which HIV transmission is unlikely

Looking closely at the first assumption, there have only been a handful of studies that have aimed to establish where there is actual sperm in pre-seminal fluid. Most of these studies have been small and showed mixed results

One 2010 study in  Human Fertility showed that, of 27 male participants who ejaculated, 11 produced pre-seminal fluid containing sperm. Of these, 10 had motile sperm in their samples.

The bigger question whether this actually matters. While semen is known to be a dominant carrier of HIV, there has long been debate as to whether the sperm "carries" HIV or whether the virus is just free circulating in the seminal fluid.

Most research today suggests that it's both and then some. In addition to free-circulating virus, sperm interacts with elements on HIV's outer shell, called heparan sulfate and mannose receptors, effectively sticking the two together like velcro.

In this capacity, sperm as a viral carrier and is more easily able to pass the virus to vulnerable white blood cells (called dendritic cells) that are found around microabrasions in the vaginal or anal lining that often form during intercourse.

Moreover, the carrier will have a pH similar to that of the vaginal, suggesting that it may have a greater chance of penetrating the mucosal lining of the vagina.

While this may suggest that sperm plays a bigger part in HIV infection that the fluid itself, there is one spoiler: men with vasectomies can pass HIV to their partners.

As such, it leaves the question as to whether volumes of seminal fluid is key to infection.

And while it certainly seems a fair argument, there can really effective way to know how little is "safe" and how much is"unsafe."

A Word From Verywell

If you are concerned that you may have been infected with HIV, see a doctor for an HIV test. If you have not been infected, protect yourself by understanding the tools of prevention, including safe sex, condoms, and pre-exposure prophylaxis (PrEP).

Sources:

Centers for Disease Control and Prevention. "HIV/AIDS: HIV Transmission." Atlanta, Georgia; updated October 1, 2015.

Killick. S.; Leary, C.; Trussell, J.; and Guthrie, K". Sperm content of pre-ejaculatory fluid."Hum Fertil (Camb).2011; 14(1):48-52.

Tortortec, A. and Dejucq, R. "HIV infection of the male genital tract – consequences for sexual transmission and reproduction." Int J Androl. 2010;33(1): e98-e108.

Maxmen, A. "HIV sticks to sperm." Journal of Experimental Medicine. 2009; 206(12):2578.2.

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