This Commons Library briefing paper provides an overview of testing for Covid-19 in England. It covers the different types of test that are in use and in development, as well as testing capacity and the criteria for being tested.

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The World Health Organization (WHO) has strongly encouraged countries to test suspected cases of Covid-19 disease to disrupt the transmission of the SARS-CoV-2 virus and slow the rate of infection. Testing can also help support public health efforts to ‘characterise‘ the disease, so that health authorities can understand its severity, prevalence and how it is evolving.

The NHS is using an RT-PCR test to identify cases of Covid-19 in the UK. This relies on collecting genetic material (RNA) from the suspected case via a nose and/or throat swab to detect nucleic acid from the virus. The PCR test can only detect the virus while it is present in the person; it cannot tell if the person has had the virus but has since recovered. The test may also not identify those cases where the person is infected but is not showing symptoms.

‘Serological tests’ for Covid-19 are currently in development. These tests aim to identify whether the individual has previously had the virus – even if they have not shown symptoms – through using a blood or plasma sample to detect if the patient has antibodies to the virus. The Government is reported to have bought options on up to 17.5 million antibody tests, of different types, that could be used ‘at home’ rather than in a clinical setting. The effectiveness of the ‘at home’ serological tests is currently being evaluated. To date, they have not performed well, generating both false negatives and false positives.

Testing capacity for Covid-19 in has increased during the course of the outbreak, rising from 2,000 tests per day on 5 March 2020 to 12,799 by 4 April 2020 and to over 100,000 by 1 May 2020. The approach to testing has also shifted from a centralised system (where tests were processed by Public Health England laboratories) to a more distributed approach that relies on NHS laboratories, private industry and academia/research institutes. On the 2 April, the Health Secretary pledged that the UK would carry out 100,000 tests a day by the end of the month; a target which the Government announced it had met, although the inclusion of home testing has been contested.  The Government subsequently committed to increase testing capacity to 200,000 tests per day by the end of May.

The Government has been subject to criticism for not scaling up the UK’s testing capacity earlier, and more rapidly, and for failing to prepare sufficiently for the pandemic. Several reasons have been cited as to why testing capacity is not higher, including shortages of the key materials that are needed to perform and run the tests.

At the start of the outbreak, the UK pursued a testing and contact tracing policy which aimed to ‘contain’ the virus and disrupt transmission through testing suspected cases and following up with the close contacts of those who tested positive. As the UK moved from the ‘contain’ to ‘delay’ phase of its response to the virus on the 12 March, the criteria for testing narrowed to only the most severe cases. Following criticism that NHS staff were not being tested, the Government announced on the 27 March that testing would be extended to frontline NHS staff in England. On 15 April, the Government pledged that staff working in care homes in England requiring a test would be able to access one and that all symptomatic care home residents will also be tested for Covid-19.

Eligibility for testing was subsequently expanded again on 28 April 2020 to include anyone over 65 with symptoms, anyone with symptoms whose work cannot be done from home as well as social care workers and residents in care homes (with or without symptoms). On 18 May 2020, the Health Secretary announced that everyone aged 5 and over with symptoms of Covid-19 was now eligible to be tested.

The Government is also developing the UK’s contact tracing capabilities and has recruited 21,000 ‘manual’ contact tracers in England, while also developing an NHS contact tracing app. The app is expected to be rolled out in mid-May 2020, as part of a wider ‘test and trace’ programme.

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