Avacta halts sale of Covid-19 rapid antigen lateral flow test to boost Omicron sensitivity

Britain’s biotech firm Avacta Group on Monday (January 10) announced halting sales of its Covid-19 rapid antigen lateral flow test AffiDX to replace antibodies in the device and increase its ability to diagnose the Omicron variant.

The company stated that AffiDX is capable of detecting Omicron when the virus is present in high numbers in samples, but the sensitivity of the test reduces at lower viral loads.

The performance of all rapid antigen tests came under scanner in wake of a large number of mutations in the Omicron variant.

AffiDX contains both a proprietary Affimer reagent and a commercially available antibody.

The Affimer reagent detects the Omicron variant with the same sensitivity as the Delta variant, and performance of the antibody is paired with the Affimer reagent in the test. This has been affected by the additional Omicron mutations, the firm said.

Alastair Smith, chief executive of Avacta Group, said: “Our determination to only provide high quality, high performance diagnostic tests has led us to the correct decision to pause all marketing of the AffiDX® lateral flow antigen test. We have, of course, been unable to market the product in the UK since October 2021, as the product continues to await approval under the new CTDA regulatory process.

“We believe Covid-19 testing remains a long-term commercial opportunity. We will therefore use the robustness of the Affimer® platform, and what we have learned about the SARS-CoV-2 virus, to generate the next generation antigen test that will be as resilient as possible to any future mutations."

He added that performance of other marketed antigen lateral flow tests may also be affected by the new variant, which is already dominant in several countries.

Smith suggested conducting similar Omicron sensitivity studies on all antigen tests and the results be communicated to the public to generate confidence in the results.