How HIV turns an infection into a hidden genetic record
HIV arrives with its genetic instructions written in RNA, but a human cell stores its own genes as DNA. After entering a cell, the virus uses an enzyme called reverse transcriptase to copy its RNA into DNA. A second viral enzyme, integrase, inserts that DNA into one of the cell’s chromosomes—the long, packaged strands of DNA that hold the cell’s genes.
Once inserted, the viral sequence is called a provirus. It is copied along with the cell’s DNA whenever that cell divides. The virus has not merely left material behind: it has made part of its life cycle a durable feature of the infected cell.
Why the viral instructions can go quiet
Integration does not mean the cell immediately produces new viruses. In some infected immune cells, the provirus becomes latent: the cell remains alive, but the viral genes are largely switched off. The infected cell can look much like an uninfected one, so the immune system may not recognize it as a target. Some such cells can persist for years, and dividing cells can pass the inserted viral DNA to their descendants.
Other infected cells actively read the provirus, make viral RNA and proteins, and assemble new virus particles. HIV’s ability to occupy both states—active and quiet—helps it persist even when its replication is controlled.
Why suppression is not the same as removal
Antiretroviral medicines interrupt steps HIV needs to make copies of itself. With treatment, the amount of virus in the blood can fall to very low levels, but a quiet provirus does not need to make new virus for its DNA to remain inside a cell. Most treatment therefore controls ongoing infection without excising every integrated copy.
That is why stopping treatment can allow HIV to rebound: a latent cell may become active again and restart production. The enduring challenge is not simply to block the virus while it is making copies, but to find and eliminate—or permanently silence—the infected cells carrying its hidden genetic record.
