Developing a Covid-19 testing strategy with local, national and global impact

Dr Bob Klaber is a consultant paediatrician and the Trust’s director of strategy, research and innovation. Alongside Dr Fran Cleugh, he has led the Trust’s efforts to develop a Covid-19 testing strategy that meets the needs of our staff, patients and wider community, bringing in innovations and learning from the rest of the NHS and worldwide. Here, he sets out our strategy for testing and how it fits with the government’s testing ambitions, making sense of the different types of test available along the way.

When the new coronavirus first became part of our lives in early 2020, we knew little about it. We’re still trying to deepen our understanding of how it is transmitted and how it affects us, including the full range of impacts it can have on different individuals. As the whole world grapples with how to cope with Covid-19, it is clear that an effective approach to testing is going to be key for managing the disease over the coming months and, potentially, much longer.

However, rolling out a large-scale testing approach has proved challenging, both nationally and locally. Early on, as we learned more about the potential and limitations of various testing approaches, global demand for existing Covid-19 tests exploded and key components, such as reagents, grew scarce.

Some hospitals struggled to maintain enough supplies to meet essential testing demand. This became frustrating for staff who also worried about their own health and the possibility of passing the virus on to those closest to them. Large-scale, dedicated staff testing programmes were established centrally but these also proved challenging to access for many. Clinicians and researchers were already working to improve testing, but it didn’t feel fast enough to keep up with the way the coronavirus was spreading in the UK.

In this context, we set out to develop our own local strategy – for patients and staff – while fostering innovation and research that can make a difference in the national and global fight against coronavirus. Our approach has drawn heavily on the skills and resources of North West London Pathology – a collaboration between our Trust, Chelsea and Westminster and Hillingdon Hospitals – as well as Imperial College. We’ve also been careful to coordinate with NHS partners across our north west London sector.

Though the testing picture is still complex, we believe we’ve developed an innovative, adaptable approach for our Trust that we can build on, helping to improve our understanding of and response to the virus while also keeping our patients and staff safe.

PCR testing to inform our clinical pathways

The viral polymerase chain reaction (PCR) test for coronavirus is the most common in current use. A sample is taken by placing a swab into your nose and/or throat, then placing it in a test tube and sending it to a lab to be analysed. The PCR test looks for evidence of the virus in your body right now, by detecting the presence of genetic material in the virus called RNA. The PCR test can therefore only tell us if the virus is currently present in the body.

This is what we have used most in our hospitals. In the early days of our response, we used a combination of symptom identification and testing to help us to diagnose Covid-19 in individual patients and guide us on where they would be best cared for in our hospitals.

As we move into the next phase of our Covid-19 response, we’re reviewing all of our clinical pathways to determine how we can best resume our wider services – planned and urgent and emergency – while keeping everyone as safe as possible. We need to protect patients who definitely do not have coronavirus from becoming infected (Covid-protected pathways) and to minimise risk when we don’t know whether or not patients are infected (Covid-risk-managed pathways). We will, of course, also need to continue to care for patients who are definitely positive for coronavirus in single rooms or in ‘cohorted’ wards. A comprehensive and regular testing programme is essential to making this work. We’re already testing all inpatients on admission and regularly testing patients who are receiving on-going treatment, such as renal dialysis or chemotherapy. We are now working up a process for testing patients before they come into hospital for when we resume planned surgery and other procedures in order to ensure we are able to protect some areas of our hospitals from Covid-19 completely.

Developing rapid PCR tests

We always aim to identify what’s causing our patients to be unwell as early as possible. An early diagnosis allows us to get each of our patients onto the best possible treatment as quickly as possible. It also gives us greater clarity on what is going on, allowing us to offer clear options to each individual. This helps us make decisions together, ensuring everyone can play a part in developing their own care plans wherever possible.

The most commonly used viral PCR test takes 12 to 24 hours to process and deliver results. If we can get results to inform decision making within the first couple of hours of seeing a patient, we can start treatment and management earlier in the disease’s progression and hopefully prevent patients from deteriorating.

We are working with Imperial College London to stand up a PCR testing programme that will help deliver results more quickly and we’ve already implemented this for patients in some areas. The DnaNudge test can be undertaken in the hospital, at the point of care, by simply loading a sample in to a cartridge system. It provides results in around 90 minutes and, for some areas, such as maternity and A&E, where patients are usually unable to predict their visit, this could have a huge impact on patient care.

PCR testing for staff

We recognised early on the importance of providing tests in-house for symptomatic staff as well as for symptomatic members of their household. Having – or living with someone with – symptoms triggers self-isolation, of at least seven or 14 days, respectively. Not only does testing provide reassurance to our staff and help them get the care they need, it also enables staff to return to work as soon as they are ready, minimising disruption due to staff absence.

From the outset of the pandemic, we’ve worked hard to increase our testing capacity. This has included significant extra resource at North West London Pathology as well as setting up an additional lab in partnership with Imperial College. This meant that, as soon as we were able, we launched an on-site testing programme for staff displaying symptoms of coronavirus, as well as any member of their household displaying symptoms. This testing programme continues and we encourage any staff with symptoms, or with a member of their household who has symptoms, however mild, to request a test.

When we paused some of our clinical services to respond to the virus, a wonderful group of staff were redeployed to support the testing programme. They helped launch testing points at our three main sites, enabling colleagues showing symptoms of coronavirus to get tested on their way home to self-isolate as well as to come in for testing.

Importantly, our staff testing programme helps us build a picture of infection rates among our staff, contributing to our understanding of the transmission of the disease in our community and who is vulnerable. It can also help us as we move through our response, for example informing self-isolation guidance and identifying areas or groups with a higher than average rate of infection for further investigation. It will also be able to link into local and national efforts to trace and isolate contacts, following a positive test.

One of the biggest challenges with Covid-19 is understanding the spread of the disease among people who do not show symptoms – either because they have a mild reaction to the virus or because symptoms from a stronger reaction have not yet developed. This is also a priority for us and, again, is essential to being able to separate our clinical pathways and keeping key areas completely protected from Covid-19. We were already beginning to develop our asymptomatic testing programme when, at the end of April, the Department of Health and Social Care asked us to test asymptomatic staff as part of a national pilot.

We quickly stood up a two-day testing programme to try to understand prevalence in our staff community. We tested more than 2,000 staff and found that about three per cent had coronavirus RNA present in their bodies at the time of testing. Staff who tested positive self-isolated immediately and their colleagues were informed so that they could monitor themselves carefully for possible infection.

The pilot was a snapshot in time that provided some incredibly helpful insights that are now informing the development of widespread PCR testing for both staff and patients:

  • Asymptomatic staff were offered a retest on day eight or ten following their seven-day isolation – almost all of those who were tested again had a negative second result, so we were able to confirm that a seven-day isolation is adequate for asymptomatic staff with a positive test.
  • We asked staff to administer the tests themselves, to help us improve the self-swabbing guidance that will support at-home testing in general. We found that supervised self-swabbing was successful as a technique, so this will help to inform our future approach, not least with the potential for home swabbing for people on pre-operative elective care pathways.
  • Cases were spread relatively evenly across the Trust with no significant differences identified between males and females or between black and minority ethnic (BAME) staff and white staff.
  • The test does not provide us with any information about how or where someone has been infected and, interestingly, we did not pick up any significant differences between staff working in Covid patient areas compared to non-Covid areas, or even clinical staff compared to non-clinical staff.

Antibody testing

Antibody tests, also known as serology tests, have been widely covered in the media because they have the potential to tell us a lot about who might have previously been infected with coronavirus. An antibody test, which is best taken as a blood sample from a vein, detects the presence of the antibodies that are produced as a result of the body’s response to coronavirus. If antibodies are present in your blood, this suggests that you may have previously been exposed to or infected with coronavirus. This test can’t tell you if you are currently infected with coronavirus.

The accuracy and validity of antibody testing has improved exponentially over the last few weeks, thanks to concentrated efforts from researchers across the world and they are beginning to be used within the general population. This includes research some of our staff have volunteered for as part of the REACT study. As scientists continue their work to understand more about immunity and to develop a vaccine, antibody testing will be an important part of our national response, giving us valuable information about previous infection rates.

We know from the study of other viruses that antibodies are often quite specific to the type of virus that triggered their production and their presence indicates a degree of immunity against catching that same virus again. Scientists are hopeful this is the case for this new coronavirus but, because it is so new, there are some things about the antibodies that we don't know for certain yet:

  • we do not currently know how long coronavirus antibodies stay in our bodies
  • we do not know for certain if antibodies provide any degree of immunity from further coronavirus infection
  • we do not know whether or not having these antibodies makes you any less infectious to other people 

The only fact that a positive antibody test can confirm at the moment is that you are very likely to have previously been exposed to or infected with coronavirus. Therefore, we cannot currently use individual antibody test results to guide clinical decisions, but the results will give us a sense of how many people across our workforce and wider communities have previously been infected.

To be very clear, antibody test results – whether positive or negative – will not change patient pathways or, for staff, working practices or areas of work. They also do not change the requirement to follow national advice on social distancing and isolation in case of contact with people infected with coronavirus.

As we start to learn the answers to these questions, data we already have from antibody testing will be vital. The government recently announced the start of a major new national antibody testing programme, with plans to provide them to NHS staff in England from the end of May. Clinicians will also be able to request antibody tests for patients in hospital if they deem it to be clinically appropriate. We are continuing to work closely with colleagues in North West London Pathology and Imperial College to implement an antibody testing protocol that we believe offers the most accurate test available.

Our own antibody testing programme is being piloted now and we roll out fully in the first week of June. This will be a formal programme that will initially run over 6-8 weeks and will be available to all of our staff and many of our inpatients.

Research and innovation

We’re working very closely with Imperial College London on lots of research around coronavirus and so we know how important innovation will be to tackling it in the long term. Testing is no exception. We’re constantly evaluating our existing testing programme for staff and looking at ways to develop new approaches that could lead to us getting faster, more reliable results.

But we’re also contributing to innovating testing and, as part of an academic health science centre, it’s important that we share our knowledge, expertise and experience nationally and even globally. One programme, commissioned by the Department of Health and Social Care and led by colleagues at Imperial College London with Ipsos MORI, involves 100,000 at-home test kits being sent to randomly selected individuals from 315 local authorities across England to get a sense of how many people are currently infected with the virus.

The Trust is heavily involved with the second part of this programme which will see researchers start to investigate the accuracy and usability of at-home antibody testing, so this can be validated for wider use. More than 250 of our staff who have had a positive test for Covid-19 have volunteered to participate in this trial to help establish the accuracy of the test. We appreciate all of the many volunteers who are helping across all areas of research.

Engaging and communicating with staff, patients and our local community

Our understanding of the virus is evolving very quickly and, with all the information around testing and potential treatments, it can be hard to keep facts straight. We are committed to proactively working with our staff, patients and local community to help everyone understand our strategy for testing as well as for treating Covid-19. We are working hard to provide clear and up-to-date information on the latest developments and how we’re working with local, national and international clinicians and researchers to develop the best testing and treatment solutions.

Learn more about Covid-19 innovations as well as tests available to our staff and patients and share this post on social media to help raise wider awareness.