Researchers in Vancouver report that those infected with strains of HIV already resistant to some antiretroviral medications can still exhibit resistance to the drugs as long as three years after infection, AIDSmap.com reports. The study undermines a widespread belief that HIV typically reverts to a more drug-sensitive, wild-type strain in the body when antiretroviral drugs are not being taken. The researchers followed two newly infected patients, one of whom contracted HIV through intravenous drug use and remained off treatment for nearly three years, and another infected through unprotected sex. The first patient maintained virus with genetic mutations conveying resistance to protease inhibitors and several reserve transcriptase inhibitors three years after infection. The second patient maintained a reverse transcriptase inhibitor mutation.
The researchers theorize that drug-resistant virus persisted in the bodies of the study subjects because there was no initial wild-type virus pool in their bodies and therefore no hidden wild-type reservoirs to reseed the body with HIV in the absence of drug therapy. Because of this, they recommend resistance testing for all newly diagnosed patients. Previous studies have shown that HIV typically reverts to a wild-type strain when all drugs are stopped in patients initially infected with wild-type virus but who develop drug-resistant virus while taking anti-HIV medications.