How might mass testing work in Lancashire - and is it accurate enough?

It remains unclear what kind of support Lancashire will receive to implement a Covid mass testing programme after it falls under the toughest Tier 3 restrictions next week.

By Paul Faulkner
Saturday, 28th November 2020, 3:37 pm
Updated Saturday, 28th November 2020, 3:40 pm

When the government pledged that areas subject to the most stringent post-lockdown rules would be enabled to create a rapid-result community testing regime, speculation grew that it would look like the army-run initiative in Liverpool, under which everybody was encouraged to take a test.

However, with of the country due to enter Tier 3 on Wednesday, questions are now being raised about the capacity for such ambitious programmes to be rolled out in all of the affected areas.

Lancashire last week began to deploy a smaller-scale testing initiative, which will see certain key sectors targeted. So far, staff in council-run day services and Lancashire Fire and Rescue Service are being invited for tests - and the scheme will expand in the coming weeks to those working in other emergency services and also schools.

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Tier 3 areas like Lancashire have been promised mass testing programmes

Under that arrangement, there will eventually be sufficient capacity to test 10 percent of the county’s 1.5 million population each week.

“We are looking to work with the government on the back of the Tier 3 announcement for a whole different scale of mass testing going forward,” Dr. Karunanithi told a press conference.

However, speaking separately to the Local Democracy Reporting Service shortly before that announcement, he explained that the accuracy of the so-called “lateral flow tests” meant that repeat testing was the most effective way to deploy them.

Research by Oxford University and Public Health England found that lateral flow tests detect 76.8 percent of Covid-positive cases when administered by a health professional, although that rate falls if they are carried out by others who have received training. They have a specificity of 99.68 percent - meaning that their false positive rate of 0.32 percent.

“Using it as a one-off test is less accurate than repeat testing for the same individuals. Two or more constituted negative tests will give us much more confidence in saying that an individual isn’t infectious at the time of testing.

“The technology allows us to get the results then and there - and the more we test, the more we will be able to find people with the disease, but also offer reassurance to those without it.

"It also means we can offer the necessary support on the spot, rather than risking delays in the national system," Dr. Karunanithi said.