The isolation of HIV has been demonstrated according to Koch's postulates, which are a set of criteria used to establish a causal relationship between a microbe and a disease. The isolation of HIV was first reported in 1983 by researchers at the Pasteur Institute in France, who used a technique called co-cultivation to isolate the virus from patients with AIDS. Since then, HIV has been isolated and characterized using a variety of methods, including virus culture, electron microscopy, and molecular biology techniques.

Computer modeling is not the sole basis for the link between HIV and AIDS. While computer models have been used to predict the course of the HIV epidemic and to evaluate the effectiveness of different treatment strategies, the link between HIV and AIDS is based on a large body of experimental and clinical evidence. This evidence includes the isolation and characterization of HIV, the observation that HIV-positive individuals are at increased risk for developing AIDS, and the effectiveness of antiretroviral therapy in preventing the progression of HIV infection to AIDS. Similarly, the link between SARS-CoV-2 and COVID-19 is based on a wide range of clinical and epidemiological evidence, including the isolation and characterization of the virus, the observation that COVID-19 is caused by SARS-CoV-2 infection, and the effectiveness of vaccines and other interventions in preventing and treating COVID-19.