Paula Barker MP, Wavertree
Ian Byrne MP, Liverpool West Derby
Dan Carden MP, Walton
Maria Eagle MP, Garston and Halewood
Kim Johnson MP, Liverpool Riverside
05 November 2020
Asymptomatic covid-19 screening in Liverpool
We are writing to you in response to the apparently hurried decision to begin population-wide testing in Liverpool, as part of the £100 + billion ‘Operation Moonshot’, in order to “find positive cases and to break chains of transmission” (Government press release, 03 November 2020).
This announcement is inconsistent with the SAGE advice at its 56th meeting on 10 September 2020 that it had “high confidence” that “Prioritising rapid testing of symptomatic people is likely to have a greater impact on identifying positive cases and reducing transmission than frequent testing of asymptomatic people in an outbreak area”. This chimes with WHO guidance to focus on contact tracing and identification of clusters, and which does not recommend mass screening. Proposals for mass screening in their current form will undermine this priority.
Searching for symptomless yet infectious people is like searching for needles that appear transiently in haystacks. The potential for harmful diversion of resources and public money is vast. Also of concern are the potential vested interests of commercial companies supplying new and as yet inadequately evaluated tests. If the programme is to proceed, then the contracts awarded, or advertised, should be made public, including their cost to the public purse. (The government is already facing a judicial review for failing to publish covid-19 contracts, brought by your fellow MPs Debbie Abrahams, Layla Moran and Caroline Lucas with the Good Law Project.)
There is currently no evidence demonstrating that SARS-CoV-2 screening can bring benefit cost-efficiently, and experience shows that unless screening is delivered as a systematic programme with quality assurance for every step of the pathway then any theoretical benefit will not be realised in practice, even where a benefit is possible.
We would like to ask you what has been decided, and how were decisions reached, regarding the types of tests to be used, what exactly are they aiming to detect, and how has their accuracy been evaluated? We understand that the Liverpool pilot is likely to use a direct LAMP test (Optigene) and a lateral flow assay (Innova). Currently there is little or no evidence of the accuracy of either of these tests from their use in presymptomatic and asymptomatic cases, or in field settings. There is substantial uncertainty as to whether they can detect the lower viral loads that are likely in symptomless people, which appears to be the aim of this mass pilot. If the tests fail to detect cases, then the programme will waste resources and time, and give people false reassurance which could increase transmission. Similarly, the false positive rates of these tests have not been established in community use and neither have the implications for contact tracing services. Evaluations of other similar tests by the WHO has suggested between 1% and 5% of people without infection may get false positive findings. This means that if 1 in 100 people tested in the pilot have asymptomatic infections, as few as 1 in 5 of those getting positive results will actually have Covid-19 – and 4 out of 5 would be false positives and they and their contacts would unnecessarily be told to isolate.
The accuracy of tests for identifying symptomless infection in a healthy population need to be evaluated in a pilot study with proper research design to assess the extent to which asymptomatic people contribute to overall case-loads, whether they play a significant role in transmission, and whether screening can help. We see no evidence that the Liverpool project has such a research design.
It appears unclear what will happen when people test positive, and negative, whether there will be clinical oversight in interpretation of the results and whether the results will be sent to patients’ GPs and integrated with medical records. What will people be offered? What will they be instructed to do? What support structures are in place to achieve this? It is also unclear how this programme will be integrated into, and affect, the track and trace system, which is already performing poorly.
Are all the above considerations documented in a format suitable for the lay public to understand as part of an opt-in informed consent process? Is there an option to withdraw from the scheme at any stage, including freeing people of any study requirements? Are participants afforded the right to access their information, to know with whom it is being shared, and to request its deletion – in line with GDPR and the Data Protection Act?
These are just some of the questions and issues that are concerning us and that need to be pursued, along with asking the government to explain why they are acting inconsistently with SAGE’s advice. We urge you to do so as soon as possible.
If we can be of any assistance, please do not hesitate to contact us.
Professor of Public Health, Newcastle University
Anthony J Brooks
Professor of Genomics and Bioinformatics, Leicester University
General Practitioner and Academic Fellow in General Practice, Glasgow University
Angela E Raffle
Consultant in Public Health, Honorary Senior Lecturer in Public Health, University of Bristol
Lecturer, University of Cambridge
Response from Kim Johnson MP
Thank you for your e-mail. The testing pilot in Liverpool is a matter between the Government and the local authority, so I am unable to answer your questions. I have, however, passed this across to our Director of Public Health who may well have the information you seek on what is a pilot project.
Kim Johnson MP