Welcome to the forum.
Reacting first to the title you chose, before reading the question itself: Fingering has never been known to transmit HIV, and presence or absence of menstrual blood is not likely to have any effect.
Now I have read the question. First, it is statistically unlikely your fingering partner has HIV; even among the most sexually active heterosexual women in the US and other industrialized countries, on average fewer than 1 in 1,000 have HIV. Second, fingering has never been known to transmit HIV, and it is fair to assume there have been billions of fingering episodes in the presence of menstrual blood, with and without hangnails, finger cuts, etc. Third, cuts and nicks on the hands are potential entry points for HIV primarily if the cut is fresh (actively bleeding) and deep.
So for sure you do not need PEP; based on the information here, you wouldn't be able to find a doctor or clinic willing to prescribe it anyway. From a medical standpoint, you don't need HIV testing either -- but of course you are free to do that, if my words do not completely resolve your concerns and you would feel better having a negative test result. Anyway, all people who are sexually active and not monogamous should have HIV testing every year or two -- so perhaps it's time on that basis. But not because of this particular event.
Finally, have you spoken with your partner? Why not just ask her if she has HIV or other STDs? She'll probably say no, which might also help reduce your anxiety about it.
Regards-- HHH, MD
Hi Dr. Handsfield,
Thanks for your response, an expert's view really does put things into perspective. Conceptually I still find it difficult in biological terms, how a microscopic virus couldn't find entry via some form of liaison new - or old on the finger given it was being moved around the inside of a partners vagina. But perhaps I am over-thinking this? But it's very reassuring to know there are few [if any] cases of this happening.
If you could humor me though, if a healthcare worker such as a Doctor/Nurse/Phlebotomist got a substantial amount of blood on their hands from a patient, would this not be a serious occurrence?
Thanks again for your council, I won't have any more follow up queries.
You are indeed overthinking things somewhat, but you're not alone. Many people incorrectly assume that "just one virus" is enough for transmission. But thanks for asking it. Although the answer isn't new, it bears repeating from time to time -- so this gives me an opportunity for a blog-like answer so I can bookmark this thread for future replies to similar questions.
In fact, HIV transmission is inherently inefficient. Large amounts of the virus must have direct contact with substantial numbers of susceptible cells. Think of it like the egg and sperm: remember those biology or health education pictures in junior high? it takes thousands of sperm trying to fertilize the egg for one to be lucky enough to get in. A normal sperm count is around 15 million per ml (that's 1/5 of a teaspoon). While in theory a man with a low sperm count could father a child, since only one sperm has to get into the egg, in fact men with counts of under 1 million usually are infertile, and those at 100,000 are never successful without special procedures (like in vitro fertlization with sperm concentration techniques).
HIV transmission is biologically different than fertilization, but the numerical analogy is appropriate: it requires exposure to large amounts of virus to create a significant risk of transmission. This is why even with unrpotected vaginal sex with an infected male partner, the average HIV transmission risk for the woman is around once for every 2,000 exposures -- and that's with large amounts of virus deposited deep in the body.
For the same reasons, a medical worker with the exposure you describe would not be considered at risk. To my knowledge, every known HIV transmission to a health care worker resulted from a physical injury (usually a deep needle wound or an overt scalpel slash) in the presence of HIV contaminated blood; or a large exposure to the eyes of contaminated blood or body secretions.
These are also the reasons that HIV is not transmitted in the environment. No cases have ever been known to be acquired, for example, by hand shaking, contaminated door knobs, shared eating utensils or bathrooms, etc. Even when the virus is present in moist blood or secretions left on such objects, there is too little of it, and too little exposure to susceptible cells, for transmission to occur. (On top of that, HIV dies rapidly when infected fluids dry out.)