Trini-Screen, Trinity’s own campus-based Covid-19 screening programme, is still in its early days, but with backing from campus residents, it has the potential to change the way we test for the virus in the future.
Plans for on-campus testing were in the works from early in the pandemic. In March, Professor Orla Sheils, the Dean of Health Sciences and now the principal investigator in the Trini-Screen project, was at the forefront of the medical discourse on how to deal with the emerging crisis. Sheils background is in molecular diagnostics and the design of tests for clinical settings, so she had a vital skillset in the early stages of the pandemic and was involved in meetings with other medical leaders, ministers, and then-Taoiseach Leo Varadkar.
Sheils described concerns at the start of the pandemic that the RT-PCR test, which is used in HSE testing, was time-intensive, and that multiple tests were potentially needed. Speaking to Trinity News, Sheils explained that “as the HSE was getting to grips with the scale of the pandemic back in March-April, it seemed giving people a one-stop test wasn’t really going to be enough because there’s a window where you might be infected, but not transmitting the virus. And, equally, you may have been positive but have stopped transmitting.”
To combat this, there was talk of testing twice, seven days apart. But this would have put enormous pressure on a system that was already struggling to find its feet. So, experts like herself were looking for faster alternatives to the standard RT-PCR test if a two-test system was required. One such faster testing method is the LAMP assay, now being utilised by the researchers in Trini-Screen.
It might be useful to the HSE, but more importantly, it will help to keep Trinity students and staff as safe as we can during this pandemic
From this came the two-pronged aim of Trini-Screen: to gauge the viability of the LAMP diagnostic test as a supplementary Covid testing technique and to collect data that might be useful to the HSE, but more importantly “to keep Trinity students and staff as safe as we can during this pandemic”:
“We were looking at ways to try and make college as robust as it could be with regards to opening,” Sheils says. “We were very aware that, as a city-centre campus, we would be asking people who were residents in Dublin to come in using public transport, maybe use coffee shops etc. So we were thinking of things that we could do that would reassure staff and students, but also the population at large, that Trinity wasn’t a risk.”
The current Trini-Screen programme is in a pilot stage and is available only to those in College residence, either on campus or in Halls. This opens the trial up to a possible 2,000 participants but uptake has been unfortunately lacklustre. About 10% of those in residence and eligible for the screening programme are currently taking part. “The uptake hasn’t been very good, I’m afraid, people haven’t been keen to participate. I’m not really sure why because it seemed to me a bit like a no brainer.”
Participants collect their own sample and leave it in a designated collection point.
The screenings are carried out weekly for participants on a designated day. The critical benefit of the Trini-Screen technique and the LAMP assay is that participants collect their own sample and leave it in a designated collection point. They do not come in contact with researchers at all. “The HSE test involves going to a designated centre and having a nasal pharyngeal swab. I thought that would be a bit too onerous. So we’re doing an experiment which is using saliva.”
The saliva is collected by participants using specifically designed collection tubes. These are labelled, placed in a biohazard-grade plastic bag, and deposited into the designated collection box. Then researchers at Trinity Translational Medicine Institute (TTMI) at St. James’s Hospital process all the anonymous, numbered samples.
Sheils acknowledges that the LAMP assay is less sensitive than the gold standard RTPCR test used by the HSE. “To mitigate that, we feel that if we do it regularly, so on a weekly basis, you end up having a system that’s really quite robust.” This is a common practice in medical diagnostics, where less sensitive screenings are carried out more frequently to ensure similar overall accuracy.
“The chemistry of the LAMP assay is different. It’s a type of assay that has been used in healthcare settings, sometimes in point of care where you want a quick result and where there are technical challenges. So a good example would be during the Ebola outbreak, when this type of LAMP assay was used because it could be deployed to field areas and it could be processed quickly.”
With the continuous check-in nature of the Trini-Screen approach, small losses of accuracy are negated by the regularity of testing. Trini-Screen is less of a confirmation test for those showing symptoms or with known close Covid-positive contacts, and more of a test for the asymptomatic or those not yet showing symptoms who have the potential to become super spreaders: “We’re not worrying so much about the people who are symptomatic, because obviously if you have a terrible temperature, or if you’re coughing up a lung, you’re not going to go out and spread it. The concern is that most of the transmission or much of the transmission may be from people who are asymptomatic.”
The HSE testing service does not currently have the ability to test these types of people, because there is no reason to distinguish them from those without the virus. Simply put, we can’t test everyone, as much as we might want to. So this is why quicker, cheaper, more large scale testing methods like those being used at Trini-Screen are needed. Sheil suggests this type of augmented testing could be put in place in known high transmission areas such as meat processing plants or direct provision centres to catch invisible spreaders before serious transmission can occur. This just is not feasible at the moment with the HSE’s gold standard test, and until the research comes back from programmes like Trini-Screen, the HSE cannot implement other methods.
When Trini-Screen researchers detect a positive sample from a participant, they pass the participant number on to the College health service. The medical professionals at the health service can then relate this number to a participant’s contact information and contact the individual with further advice. The individual then follows normal HSE procedures, is tested by the HSE, and goes through the contact tracing process. “The idea is to try and minimise the amount of time a person would have when they don’t know that they’re carrying or transmitting the virus and to try and lock it down as tightly as possible and as quickly as possible,” Sheils says.
The additional HSE Covid-19 test is necessary as a positive using the LAMP testing technique may not guarantee the same result using the HSE’s test. “It’s not a diagnostic test, what we’re doing, so I just wanted to be sure that we have all of the bases covered. It’s a different type of sample, so there could be glitches with the chemistry, that means something looks positive in our test, but to be sure, we then try and make sure that they have a proper HSE test to follow up,” says Sheils.
Besides the obvious advantage of cutting down on the time that asymptomatic spreading occurs for, using the LAMP assay is also significantly cheaper, by a factor of ten, than the HSE method. This could allow it to be used much more widely than the current testing method. “We’re hoping that the Trinity group would be a sort of an exemplar model system that would say, here’s what happens when we test people serially, and you can have that data. And if it helps the country then disperse the testing capacity that it has better than it’s a win-win.”
For any of the important work being done by Trini-Screen to have a real impact, they need a greater uptake from those on campus. Sheils says in theory, there are just under 2,000 residents who could participate in the study, and at this capacity, the lab would process 400 samples a day. The program is prepared and equipped to deal with this volume of testing. Currently, however, Sheils says the most samples they have received to process in a day is around 75. It is clear that the Trini-Screen service is being underutilised, and without the student input, the programme cannot achieve its aims.
Sheils acknowledges that looking past this pilot stage of the screening programme, there are uncertainties. With such poor uptake from residents, the viability of the programme has to be questioned. They may have to move to other subsets of the college community who may be more open to the testing if they even get the go-ahead to continue. “I think if there is an appetite for it and if the results were proving useful, then I’m sure the Provost would be amenable to extending it. And it may be that it’s extended beyond just students and staff in residence. So it could be that there are other targeted groups that will be added in.”
The programme is still open to participants in College residences, and the benefits of participating make it very unclear why the uptake has been so low. On a personal level, participants have increased awareness of their own health and Covid status. Then in the college community, the faster identification of those transmitting the virus can prevent outbreaks in Trinity and help to resume normal college life as quickly as possible. Apart from this, the study could help on a national scale, by providing the evidence needed by the HSE to enhance their current testing facilities by the additional use of more frequent, quicker and cheaper LAMP testing in high-risk areas.
It would be very disheartening to see the Trini-Screen programme, with all its potential for good, fail. I would wholeheartedly encourage those in residence not currently participating in the service to get on board. This is an opportunity for Trinity to make considerable positive change, to protect students and staff, but also to learn how to adapt our testing to return to normal life as quickly as possible. As Sheils says, the decision really is, a “no-brainer”.
