Share a cold knowledge of AIDS, just for science popularization without any guidance What are the probabilities of 0.04% and 0.08%? This is a rough estimate of the single exposure risk given by the CDC based on unprotected status if the sexual partner is confirmed to be HIV positive and has no effective treatment or unknown viral load. If you have unprotected sex with a patient with AIDS, the probability of male infection is 0.04%, and the traditional probability of female infection is 0.08%. Actually, a more accurate statement would be the probability of HIV infection. HIV is a viral infection, and AIDS is a serious immunodeficiency stage that may develop after HIV has not been treated for a long time. This probability is not to give everyone a sense of luck, but to truly recognize the risks they may face. The transmission of HIV requires several conditions to exist simultaneously. There should be enough virus in the opponent's bodily fluids, and the virus should enter their mucous membranes, damaged skin, or blood circulation through blood, semen, vaginal secretions, rectal secretions, etc. Common high-risk scenarios include unprotected anal sex, unprotected vaginal sex, and sharing injection needles, especially when the other party is HIV positive, untreated, and the viral load is unknown. Ordinary handshakes, hugs, shared utensils, sweat, urine, full skin contact, and regular kissing are unlikely to transmit HIV. The CDC also states that the chance of contracting HIV through oral sex is very low, and daily contact with saliva usually does not pose a risk of transmission. From the perspective of single exposure risk, unprotected passive anal sex, which refers to the party being penetrated, has the highest risk. The CDC's estimate is that if the other party is HIV positive and does not have condoms, pre exposure prophylaxis, or effective treatment, the risk of passive anal sex infection is approximately 1/72. Active anal sex is approximately 1/909. In unprotected vaginal intercourse, the inserted party is approximately 1/1250, and the inserted party is approximately 1/2500. The risk of sharing injection needles is also relatively high, about 1/159. This is also why the probability of gay men being infected with HIV is the highest, especially for the affected party, which is about 17 times higher than the probability of female infection and 36 times higher than the probability of male infection. Of course, these numbers are only group average estimates and do not mean that everyone's real risk is the same. The real risk will be influenced by many factors. If condoms are used correctly throughout the entire process, or if the other party regularly takes medication and maintains undetectable virus levels, the risk will be significantly reduced. There is a very important concept in HIV science popularization now, which is that not being detected means not spreading. If HIV infected individuals receive regular antiviral treatment and maintain undetectable virus levels for a long time, the risk of HIV transmission through sexual activity can be considered zero. This concept is important because many people's fear of HIV still lingers in the past. Today's HIV can be stably controlled through long-term treatment, early detection and treatment, and many infected individuals can live a normal life for a long time. Some partners may ask, if the probability of transmission of sexual contact is so low, is sexual contact the main channel of AIDS transmission? In fact, sexual contact is indeed the largest channel of AIDS transmission, because the probability of a single act of infection is low, and the main way of transmission at the population level, these two things are not contradictory. The low probability of HIV infection during single sexual intercourse appears to be due to the fact that HIV is not a virus that is particularly easily transmitted through daily contact. HIV cannot be transmitted through air, water, sweat, or ordinary saliva, nor can it penetrate intact skin. To be infected, there must be a sufficient amount of blood, semen, vaginal secretions, rectal secretions, etc. that come into contact with mucous membranes, damaged tissues, or directly enter the bloodstream. A low single probability does not mean a low long-term probability. Low individual probability does not mean low overall social quantity. A single risk of less than one thousandth may seem low. But if it is a long-term sexual partner, the risk will continue to accumulate if it occurs repeatedly dozens or hundreds of times. Assuming a certain behavior has a single risk of 0.08%, which is indeed low once, but after 100 occurrences, the cumulative risk will become approximately 7.7%. If it is unprotected passive anal sex, the single risk itself is significantly higher, estimated by the CDC to be about 1.38%. The cumulative risk after 10 times is close to 13%, and the cumulative risk after 50 times can be close to 50%. This principle is like buying lottery tickets. The probability of winning a single ticket is very low, but if the whole society buys tens of millions of tickets every day, someone will definitely win in the end. 99.99% of the probability is zero if it is not duplicated, and 0.001% of the probability is correct, which is 100%. At present, HIV cannot be completely cured by ordinary drugs, but it can be treated and controlled well in the long term. The CDC has revealed that most people can control their viral load within 6 months after receiving treatment. Although HIV cannot be cured, it can enable infected individuals to live a healthy life in the long term. And if the virus level cannot be detected for a long time, it will not be transmitted through sexual activity, which means that when HIV infected individuals receive regular treatment and maintain undetectable virus levels, the risk of transmission to their partners through sexual activity is zero. Of course, the development of AIDS will be much more serious, but it does not mean that there is no cure at all. It's just that the difficulty will be much greater. At the end of this tweet, the core purpose of science popularization is not to tell everyone that the probability is low, so there is no need to be afraid, but to turn the risk of HIV from scaring others and scaring oneself into a more scientific understanding. Bitget is here, VIP! 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