People with AIDS are not allowed to donate blood because there is a large amount of HIV virus in the blood of people with AIDS. Even if a person with AIDS is in the asymptomatic HIV infection phase, the HIV virus is still present in the blood and it is only in an inactive state. If the virus is activated, it can immediately induce a systemic immune system collapse. Therefore, if the blood of HIV patients is offered to other people for use, it can cause HIV transmission. In clinical practice, there have been many people who have gone through blood transfusions that have led to the spread of AIDS. Therefore, before donating blood the CDC will test the patient’s blood for HIV, and if an AIDS patient is found to have participated in a blood donation, the use of his or her blood products should be terminated immediately.