The antiviral pills used in the study do not target the spike proteins that the immune system uses to recognise the virus.
They instead interfere with the molecular machinery that the virus uses when replicating, which has not been significantly altered in the Omicron variant.
This also allows it to potentially impact other coronaviruses than SARS-CoV-2.
One of the active ingredients, ritonavir, has seen success as a HIV treatment.
Data from Pfizer’s phase 2 study indicates their Paxlovid pill can reduce risks of hospitalisation and death by 89 percent in high-risk patients.