By Amna Karimi and Pushkala Aripaka
(Reuters) -Britain's Avacta Group is halting sales of its COVID-19 rapid antigen lateral flow test to replace antibodies in the device and boost its ability to detect the Omicron variant, the biotech firm said on Monday, sending its shares plunging nearly 27%.
The London-listed company's test, AffiDX, can detect the Omicron variant when the virus is present in high numbers in samples, but tests carried out by Avacta found AffiDX is less sensitive to Omicron at lower viral loads versus other variants.
Scientists and governments are scrambling to bolster defences against Omicron with testing, shots, therapies, and by decoding the viral genomes to try and measure how far it has spread as the variant threatens to become dominant globally.
"Our determination to only provide ... high performance diagnostic tests has led us to the ... decision to pause all marketing of the AffiDX lateral flow antigen test," Avacta CEO Alastair Smith said, urging others to also assess the sensitivity of their products to Omicron.
Experts and health authorities have warned https://www.reuters.com/business/healthcare-pharmaceuticals/rapid-nose-swab-tests-covid-may-not-detect-omicron-quickly-enough-expert-says-2022-01-07 that COVID-19 rapid antigen tests - which rely on nose swabs - may not detect Omicron quickly enough since people can transmit it in early stages of the infection before the virus reaches their nose.
The tests are popular for home and travel checkpoints for their quick results and cheaper prices compared with other elaborate tests.
While Avacta did not say when it expects to resume sales of an AffiDX test better-suited to Omicron, it said COVID-19 testing "remains a long-term commercial opportunity" for the company.
Shares in the company slid 26.5% to 85.25 pence in morning trade in London, erasing the roughly 11% gains it recorded in 2021.
Avacta and other test makers also had to pull some of their COVID-19 tests from the British market after a new review system came into force, which has not yet granted approval for their previously accepted products.
(Reporting by Amna Karimi and Pushkala Aripaka in Bengaluru; Editing by Subhranshu Sahu, Shounak Dasgupta and Emelia Sithole-Matarise)