HIV replicates rapidly with several billion new viruses made every day in a person infected with HIV. Its ability to mutate and evolve makes HIV so difficult to stop.
Reverse transcriptase, the enzyme that makes DNA copies of HIV’s RNA, often makes random mistakes. As a result, new types or strains of HIV develop in a person infected with HIV.
Some strains are harder to kill because of their ability to infect and kill other types of cells, while other strains replicate at faster rates. The more virulent and infectious strains of HIV are typically found in people who are in the late stages of infection.
Different strains of HIV can also recombine to produce an even wider range of strains. The constant changes in HIV help to evade the surveillance of immune system. Its ability to evolve rapidly is one of the major reasons why HIV is such a deadly virus. Above all antiretroviral drugs are capable of suppressing HIV, even to undetectable levels in the blood, but they cannot eliminate the virus hiding in these latent reservoirs.