Not that I want to be, also I’m not looking for medical advice, I have what I believe is a factual question, which has been stuck in my mind for years.
Some back ground: I was sexually active from the age of 21 to 39. Depending on how you count things, I was inmate with about 25 men, not every encounter lead to an exchange of bodily fluids. Too many of them were anonymous encounters that were not planned for and safe sex was not followed. In ‘93 I met Lincoln, who was HIV+ at the time, and I knew this from the start. In the six years of our relationship we were safe about 97.5% of the time. I late had sex in October of 2000, just before GWB was elected, I have been blaming him for my lack of sex, but I simply don’t want sex any more.
The TMI part: I was often the receptive partner in anal sex and during oral sex, I… um… swallowed.
So why am I not HIV+? It only takes one time, right?
The fact that A can happen after one occurence of B doesn’t mean that A will happen after one occurence of B. Sometimes Lady Luck is a bitch and sometimes she is a sweetheart.
The probability of HIV from one instance of unprotected sex of any kind is very low. See here for figures, or just click here for a simple infographic summary.
Here’s a table giving the probability of HIV infection based on particular acts.
The odds of infection for receptive anal intercourse are 138 per 10,000 acts, while the odds for oral sex are “low” (that is, so low they can’t be calculated). That works out to only about 1.4%, or one chance in about every 71 encounters where safe sex was not practiced. If your partner was on antiretroviral medication that would reduce the odds even further, reducing the already fairly small risk by 96%.
Also, some people have much higher natural resistance to HIV infection than others. A very few people have been identified that are effectively immune to HIV.
Prior to meeting my partner in 1987, I had sex with well over 1,000 men, over a 24 year period (including several years of celibacy). I have to assume that many of them were poz. With only one exception I was the “orally insertive” partner. So the exchange of body fluids involved my semen and the other guys’ saliva.
Since 1987, my partner and I have been monogamous, and neither of us is poz. His sexual history is actually MUCH more varied than mine, and his HIV status defies explanation. It has to involve much more than luck. All things considered, he must have a natural immunity to HIV.
In addition to natural immunity involving your immune system, you may have some natural resistance to the transmission path of HIV. The reason that unprotected anal sex is dangerous, is that there is usually some small tearing, and the virus gets in through tears in the skin of the rectum. Maybe yours is more resistant to tearing than most people. You also may have mucous membranes that are more resistant to allowing stuff in than average. I’m prone to allergies, that give me mucous membranes that are often irritated, and I have thin mucous, so I get colds, eye infections, and sinus infections easily. There’s bound to be a bell curve for this sort of thing, and someone’s got to be on the other end of it. If you don’t tend to get throat infections, and have healthy teeth and gums, then the virus probably won’t get in during oral sex, because skin and mucous will block it, and the enzymes in saliva, as well as the acid in your stomach will make short work of it. It’s a pretty vulnerable virus, really. If it doesn’t find an entrance right away, it doesn’t get to hang around and try to infect you after several hours. It either gets in quickly, or it dies.
IANAD, but I interpreted a few times for a safe sex program. My info is pretty out-of-date, but what I posted is some stuff that I’m assuming doesn’t change.
And then, as others have said, you can’t discount the luck factor. If you don’t want to call it luck, call it statistics. Some people get infected after a single exposure. Some people are in long-term relationships with people they don’t realize are positive, and aren’t being safe-- heck, I know of one woman who got pregnant by an HIV+ man, and neither she nor the baby ended up positive-- they are outliers on the bell curve. Somebody has to be there. You are not even the most out outlier there is, but you aren’t up on top of the curve. You’re somewhere on the “resistant,” or “lucky,” side of the curve, though.
I once saw a documentary about hemophiliacs who, in the days before effective HIV screening, were using “clotting factor” made from blood from many, many donors. The numbers were staggering. I seem to remember that a single vial of the clotting factor could contain material from as many as 10,000 donors. So, the horrific choice before them was to either be exposed to HIV or bleed to death. Nice. Of course, many, many of these people died.
But, one did not. His unexpected survival interested the scientific community. Eventually, it was discovered that he has a genetic abnormality that makes him immune to HIV. The rest of the documentary went on to say that after further research, it was discovered that this genetic irregularity was last “important” in Europe back during the Black Death. The documentary ended with the hope that this could lead to new drugs or therapies.
My partner who, before we met, had an enormously varied sexual history (in the 70s-80s), is the healthiest person I know. In the over 27 years we’ve been together, I don’t remember him even having a cold. He must have been exposed to the virus hundreds of times, but his body always rejected it. Back in the 80s, he participated in a study of people who’d been exposed, yet were still HIV-, but I don’t know what was learned from it.
Swallowing is near the bottom of the list of HIV transmission methods, risk-wise, but it’s been suggested that something as innocent as recent vigorous brushing and flossing can leave the gums more “porous” and receptive to infection than normal, so there’s no way to give an absolute answer. As said above, you probably have just been very lucky.
For panache45 - It’s entirely possible that your partner is what’s been called a long-term non progressor or “elite controller.” These are the roughly one in 300 people who have a variety of genetic surprises that inhibit HIV growth in their bodies. It’s worth noting that while LTNPs / ECs are controlling the virus in their body, they can pass the full-strength virus to other people.
