Can gene editing drive out HIV and hepatitis viruses from inside cells?

A gene-editing therapy based on CRISPR–Cas9 designed to eliminate HIV-1 infection has rekindled hopes among scientists that it may be possible to eradicate the virus and cure the infection. In an in vivo editing study in non-human primates conducted by scientists from Temple University and Excision BioTherapeutics, a single dose of a CRIPSR therapy excised the simian immunodeficiency virus (closely related to HIV-1) from the DNA of infected animals with no observable off-target effects or other safety problems. The equivalent human therapy, EBT-101, is undergoing a phase 1/2 clinical trial in people infected with HIV-1.

This CRISPR therapy is part of a wave of sophisticated genetic approaches targeting difficult-to-treat chronic infections (Table 1). In addition to gene editing, therapies, including antisense oligonucleotides, short interfering RNA (siRNA), gene therapy, therapeutic vaccines and chimeric antigen receptor (CAR)-T cell therapies, are being brought to bear on a range of pathogens, but most prominently on HIV-1 and chronic hepatitis B virus (HBV) infection.

Once a person is infected and after the acute stage resolves, these viruses can persist indefinitely — in CD4 T...