What is a COVID Rapid Antigen Test and should Australia be using them?

As Greater Sydney's COVID outbreak continues to worsen, calls are growing for Australia to introduce rapid antigen testing in an effort to keep pace with the virus, and curb the spread of the highly infectious Delta variant. But what is rapid antigen testing and how does it work?

This illustration shows a Rapid Antigen Test kit at Pharmacy Servais in Jodoigne, some 45kms south-east of Brussels on July 12, 2021 Source: AFP