Despite the difficult circumstances, we have begun our extraordinary year with only some general glitches to be resolved. All around the building, I’m hearing the joy in the voices and hearts of children as they reconnect with their friends, their teachers, their learning. As I said to all the Upper School assemblies, I missed you all terribly and it’s so good to have you “home.”
We are doing everything we can to work out the remaining glitches in various systems, but the core is working well and most are finding success with the various controls. From remembering that all temperatures should be in Celsius to the daily routines, I can sense that we are settling into some degree of stride, absorbing new practices as we go. Students are already starting to think creatively about how we can all contribute further to the PROTECT portion of our model and I’ve seen good attention to hand washing and appropriate practices throughout the building. There is a powerful understanding of our limits and the value of taking care of each other.
My thanks to all parents for your patience and I hope that our process has been helpful while making sure it’s not too daunting. It is change after all and change is always hard.
In terms of keeping you further informed, the following is a weekly feature from EpiXpert that will come occasionally and as needed to give you more information on their process.
Testing protocol
We have gone through the first round of testing during which we are using anterior nare swabs and antigen tests. Antigen tests detect the viral protein on the surface of the virus (vs PCR which detects the inside of the virus – its genetic material). As mentioned before, our tests have demonstrated 96+% sensitivity and 99+% specificity, with very narrow 95% confidence intervals (this is the range in which 95% of results fall into, the narrower, the more consistent the performance). These results are on par with PCR tests. The biggest advantage is speed and simplicity. They are also well suited for pooling because their sensitivity and specificity are not affected by pooling (samples are direct swabs so undiluted by transport medium). Antigen tests are being touted as the future of population-based screening – dependent on their availability.
Independently, we are working on validating RT-LAMP tests for use with saliva. RT-LAMP tests are a modern and simpler version of the “dinosaur” PCR method (PCR has been a novelty since the 1980s). We will provide an update on this within the next 2-3 months as this would further simplify the sample collection.
To ensure completeness of the process, if a pool comes out positive, we will isolate and retest each individual in the pool — and whoever tests as positive will be isolated and quarantined.
Swabbing technique
There are now four places accepted as equal for sample collection – nasopharynx, oropharynx, mid-turbinate, and anterior nares. We chose the anterior nares because it is less invasive for children and for more efficient for sample collection in populations. There are studies that actually demonstrated higher sensitivity of anterior nare samples as compared to the nasopharynx. Additionally, children have been shown to have 1000 times higher viral loads as compared to adults when shedding. We have also validated our tests on anterior nare samples. Hence, until we have validation of the RT-LAMP tests on pooled saliva samples, we will continue the current approach.
Even with the anterior nare swabs, there is an odd chance of discomfort or even minor irritation of the nasal mucosa. However, this is the only risk of the testing and is rather transient.