If Man A use condom for anal sex with Man B who have HIV, and after few minutes/hours, Man A reuse this same condom on Man C. Will Man C contract HIV due to the fact that this condom has come into contact with the anus of Man B?
First, to respond to this question, I will work with the assumption that man A was using a male condom. Either a male or female condom should not be re-used. One condom per ejaculation. This ensures that there is no transmission of sexually transmitted infections and other viral infections. Perhaps, at this moment I would like to understand why man A will consider re-using the condoms is it lack of access or availability? Check out this article: https://lovemattersafrica.com/birth-control/types-of-birth-control/condom
Second, to your question now, while there is no exact time that is documented on how long the virus lives outside the human body, this is because of various factors such as temperature and amount of the virus. It is documented that a virus does not survive for long once exposed to the outside environment because it is not conducive. The same applies for semen (or vaginal fluids, rectal fluids, or breast milk), the virus cannot survive longer outside the body. As soon as any of the fluids that contain HIV leave the body and are exposed to air, the fluid dries up and inactivation of the virus starts.
It is important to note that while the risk of getting infected maybe lower it will be good to be aware of other sexually transmitted infections that can be transmitted. Check out this article for more information: https://lovemattersafrica.com/safe-sex/sti-prevention/re-using-condoms-a...
Be safe and protect your partners!
Love Matters Team