Interview: Prof. David Denning discusses DenScreen and antibody testing
Prof. David Denning is professor of infectious diseases in global health at the University of Manchester and the chief medical adviser at DenScreen, a company providing a new screening system for dental patients developed during the COVID-19 pandemic. Here, he discusses the principles underpinning DenScreen and explains how its antibody testing can provide benefits to dental practices and patients alike.
Prof. Denning, thank you for taking the time to talk with us. Could you please walk us through how DenScreen works in the dental practice?
With DenScreen, two main things happen before the patient arrives. The first is that we offer a complete training package for all practice staff regarding the SARS-CoV-2 virus, how it’s transmitted, what things they can do to reduce the risk of transmission in the dental theatre, and so on. That has been lacking a bit, I think, as there’s been a lot of instruction from dental authorities, but not much in the way of training.
The second thing is that there is a triage system set up to deal with patients before they enter the dental practice. There are three main elements of this triaging: ascertaining whether the patient has previously had COVID-19 or COVID-19-like symptoms; establishing what their specific dental need is; and measuring their vulnerability if they were to contract the virus based on risk factors including sex, age, weight and the presence of pre-existing conditions.
Once the patient arrives, his or her temperature is measured and medical history and triage records are checked. If the patient has had any exposure to SARS-CoV-2 in the past, the dentist is then able to do an on-site antibody test to see if the patient has already had COVID-19. The test takes just 10 minutes and if this test result is positive—if the patient has the immunoglobin G antibody—then not only has he or she almost certainly had COVID-19, but he or she is now also at a non-infectious stage and can potentially be treated without the need for additional personal protective equipment (PPE) and fallow time on top of universal precautions.
Does the antibody test work for patients who have had COVID-19, but were asymptomatic?
It’s not as sensitive for these patients, but it’s very difficult to get extremely accurate numbers regarding this patient group. It’s also dependent on the timing of the test in relation to when the patient was ill, and sometimes you don’t know when the illness occurred. If you test for antibodies within the first two months of a patient having contracted COVID-19 in an asymptomatic manner, it’s probably going to be sensitive 75% to 80% of the time. If it’s more than three months later, this figure probably goes down to about 50%.
Your background is in infectious diseases, not dentistry. So what motivated you to co-found DenScreen?
There were a number elements to it. I have many friends and colleagues in dentistry, and when I spoke to them during this pandemic, it was quite clear that life was going to be very difficult for them, since dentists are in an occupational group that is at a very high risk of contracting the virus. We considered the fact that about 20 million people visit the dentist each year in the UK, and that, if dentists could do this antibody testing on a large scale, not only would it help to make patients and dentists feel safer, but the data gathered could also eventually become quite helpful to the national response to COVID-19.
“If dentists could do this antibody testing on a large scale [...] the data gathered could also eventually become quite helpful to the national response to COVID-19”
Is DenScreen based on any pre-existing screening systems that have already been developed?
No, we built the whole thing from scratch. We developed the triage system and relevant questions, sourced the antibody test—which was quite difficult and took a number of months—and developed DenScreen from the ground up.
You’re someone who stays abreast of the latest scientific findings and developments regarding SARS-CoV-2. Is it likely that DenScreen will be adapted as more knowledge is gained regarding this virus?
I think the basic system won’t change in its approach, and the antibody test that we’ve chosen isn’t likely to change, since it’s highly accurate and effective. As I see it, the only thing that could really change the way DenScreen is integrated into dental practices would be the widespread introduction of a SARS-CoV-2 vaccine.
Most of the scientists who are working on these vaccines around the world think that the vaccine won’t be 100% effective. This is based on prior experience with developing vaccines for other difficult diseases—for example, the typhoid vaccine is 60% to 80% effective, whereas the cholera vaccine is about 50% effective. So if we end up with a vaccine that is in this effectiveness range, it’s likely that the success of the vaccine will be measured by the antibody response, because measuring a T-cell response for a large population is a very difficult thing to achieve. In these circumstances, it would be a challenge for everybody to know whether or not they’re protected from contracting the virus, even if they’ve had the vaccine. It seems to me to be quite likely that the antibody test that we’ve got will be able to help tell if a vaccinated patient has been successfully protected.
“Most of the scientists who are working on these vaccines around the world think that the vaccine won’t be 100% effective”
Is DenScreen in place in any dental practices yet?
We have a number of practices that are using DenScreen routinely at this point. Some are using it purely for triage purposes, some are using their own triage system with DenScreen’s antibody testing, and some have taken the educational components on board while still maintaining the government’s PPE recommendations regardless of what the patient’s COVID-19 status is.
One challenge that we have in the UK is that a lot of dentistry is performed with the assistance of NHS funding, and you can’t combine a charge for an antibody test with an NHS charge. So any patients who are purely undergoing NHS-funded dental procedures are not being offered this treatment option, and as a result, it’s being offered solely in the private dentistry sector.
What has the patient response been like?
One of the things that we’ve found patients really appreciating about DenScreen is that it provides them with this antibody test to see whether or not they’ve had COVID-19 already. Here in the UK, you can’t just get this type of test at the doctor’s office, as they’ll only test to see whether patients currently have COVID-19, and so to be able to get antibody testing conducted within 10 minutes is a clear benefit.
DenScreen conducted its first continuing professional development webinar at the end of June, followed by another one on 13 August. Are there plans to make this a regular feature through the DenScreen website?
Yes, our plan is to run a webinar every month or so, when there’s new information and data that we think is worth communicating to dental professionals. Generally speaking, dentists don’t need to know the ins and outs of advances in immunology, and so these webinars are focused on providing them with learning materials that will be useful in the dental practice.