New rapid Covid tests missed more than 50% of cases in UK trial - how do they work?

New rapid coronavirus tests being trialled in Greater Manchester missed more than 50 per cent of positive cases, according to reports.

It was hoped the tests would provide a quick and easy way to find out if people had the virus, with results available in around 20 minutes

However, in a letter seen by The Guardian, scientists working on Greater Manchester’s mass testing expert group (MTEG) expressed concerns about the accuracy and sensitivity of the tests.

Is the test effective?

The test, which is part of the government’s mass-testing strategy, known as Operation Moonshot, only identified 46.7 per cent of infections during the trial in Manchester and Salford last month, according to the Guardian.

Scientists have said they have “significant concerns” after data from the North West pilot showed low sensitivity for detecting Covid.

They said: “MTEG have significant concerns and do not feel the data supported the investment in the large scale rollout of Direct RT-Lamp saliva testing in any of the proposed clinical settings considered (hospital staff, care staff, community settings) at this time.”

The government has disputed the claim that the tests are inaccurate, with the Department of Health and Social Care (DHSC) saying that results from three other trials demonstrate their effectiveness. However this data is not publicly available.