PEP works by inhibiting entry of HIV into susceptible cells. Once the body's immune system cells are invaded by HIV, there is no cure. Cell entry is believed to occur within 72 hours. In animals exposed to HIV-like viruses, treating more than 72 hours after exposure does not prevent infection.
As to the second question, I don't understand why you "remain confused". But the facts are these: Oral sex is not just a theoretical risk. It is a real risk, but the efficiency of transmission is low. Most people infected by oral sex are the oral pertners who perform fellatio on HIV infected men. Transmission in the other direction by fellatio, or by cunnilingus in either direciton, is so rare that it could be considered theoretical; some experts believe it doesn't occur at all.
Children with HIV are infected during birth or by nursing, and people used to catch HIV by blood transfusion or organ donation, although those routes now are rare. Occupational infections in health care workers are rare. Therefore, among all HIV infected adults in the world, probably over 99% were infected by vaginal or anal sex or shared injection equipment. (There is some controversy about medical injections as a source in some developing countries, but most experts do not believe that's a common route of infection.)
Best wishes-- HHH, MD
A follow-up question-
I performed oral exactly 2.5 weeks ago. A week later I had several days of night sweats. Exactly two weeks later I developed a single pronounced cold sore on my tongue. Today I began feeling severe pain in my thigh muscle. I know ARS symptoms are unreliable but it seems like I have a series of them. Any guidance you could provide on my symptoms as it relates to ARS would be appreciated.
ARS can cause night sweats (with fever) and the timing is right. Still, ARS is statistically far less likely than a garden variety virus. Cold sores (herpes) generally don't occur inside the mouth; sounds like a canker sore. Thigh muscle pain doesn't suggest ARS.
If your symptoms concern you, see a health care provider. You can be tested for HIV if you want to reassure yourself.
Two more quick questions--I know I cant determine my situation by symptoms but i still have a several more weeks of my window period and I am very nervous. I am now about 3.5 weeks since exposure. I am still feeling the muscle pain, could it be ARS related myalgia?
Is ARS related myalgia widespread throughout the body or can it be localized in one place?
Also, would the canker sore, one of them, a few weeks back be related?
Sorry for al lthe questions, I am very scared. Thank you.
Muscle aches in ARS typically occur as the body's reaction to fever, and muscle aches by themselves do not suggest ARS. When it occurs, it involves muscles throughout the body. The canker sore undoubtedly is unrelated.
There is no basis for being scared. You can expect a negative HIV test result. You don't need to wait any longer; testing will be valid now. Although it takes up to 6 weeks for some newly infected persons to develop positive tests, those with symptoms always have positive tests within ~10 days after symptoms start. So a negative result now will prove your symptoms aren't due to HIV, and will be 90% reassuring you weren't infected. You can then have a second test at 6 weeks, if you wish.
Just for clarity. I am taking your advice. I am trying to be calm. Today is the 4 week period of my window period. I know my exposure was lower risk. I know that I still have a few more weeks on my window period and will get retested just for safety reasons.
The reason I got tested today--negative, was because I was having 'symptoms'. Does your previous comment (I just want to make sure I understand it) mean that while the window period is still open, and most likely that my risks are low, the one thing we can tell is that the 'symptoms' however false they might be, are definitely NOT ARS related because of my negative results.
I hope that makes sense. Thanks for your guidance.
Probably it is not possible to have HIV symptoms and still have a negative test result at 4 weeks. The negative 4 week test proves your symptoms are not due to HIV.
That will have to be the end of this thread. You can be sure that any future tests, if you do them, will also be negative.