HIV is not contagious if the number of virus is zero, but this mainly means that it will not be transmitted through sexual intercourse. If you donate blood, it may still be contagious, because it cannot be ruled out that there is a very low level of virus in the blood, which cannot be detected by current testing methods. However, with the current level of medical technology and medical conditions, it is not possible to stop using antiviral drugs, which need to be taken for a long time, because once the drugs are stopped, they may lead to a rebound of the virus. AIDS is an incurable disease, but it can be prevented and controlled. Patients with HIV need to be treated promptly if they have an indication for ART. Most of the patients will be stable after antiviral treatment, CD4 cells will gradually increase and the number of HIV will gradually decrease, even to zero. For such patients, the treatment effect is very good.