What is the first stage of human immunodeficiency virus (HIV) infection characterized by high viral replication?

The first stage of HIV infection, known as acute HIV infection, is characterized by high viral replication. During this phase, which occurs within 2 to 4 weeks after the initial exposure to the virus, individuals may experience flu-like symptoms as the immune system begins to respond to the infection. This period is marked by a rapid increase in the viral load, which is the number of viral particles in the bloodstream, leading to a significant drop in CD4 T cell counts.

During acute HIV infection, the virus replicates aggressively, which can result in high levels of HIV in the blood and other bodily fluids. This high viral load makes this stage crucial for transmission, as the risk of spreading the virus to others is at its peak. The immune response continues to develop concurrently, and some individuals may progress to the next phase, clinical latency, where the virus is still present but replicates at much lower levels, often without causing any symptoms. This cycle is an essential part of understanding HIV's behavior and the immune response it elicits.