British biotech Avacta is withdrawing its rapid antigen test from the market over concerns that the test isn’t sensitive enough to detect cases of the Omicron variant that now make up the vast majority of infections in the U.K.
The rapid test was able to detect instances of the variant in cases where there was a high viral load. But lab testing showed the diagnostic wasn’t able to pick up cases where there was a low level of Omicron present compared to previous coronavirus variants, the company said Monday.
The decision comes amid concerns that antigen tests developed before the arrival of the Omicron variant aren’t accurate enough with the new variant, which contains a large number of mutations. Antigen tests are less accurate than PCR tests, but can be purchased over the counter and don’t require a lab technician to carry them out.
Several European countries are relying on the quick tests to support their decision to shorten coronavirus quarantine periods, with a negative result enabling people to get back to work a week or less after catching COVID. Health experts worry that “false negative” antigen tests could mean that people are returning to the workplace while still infectious.
Germany Health Minister Karl Lauterbach said on Sunday that the Paul Ehrlich Institute, a health oversight body, was conducting a review of the hundreds of rapid tests on the market to create a list of those that work with Omicron.
In Israel, health authorities are recommending that people swab their throats in addition to their nose when using rapid test kits to increase the chance of picking up Omicron, reports Reuters.
Avacta said that it will pause the sale of its rapid tests as it redesigns the product to make sure it is able to adequately detect cases of the Omicron variant. It did not indicate when the tests might return to the market.