Pandemic Response Challenge Program pillar: Rapid detection and diagnosis
Title: Molecular Assay for Instrumentless SARS-CoV-2 Rapid Diagnostic from Saliva
Closed (closing date: June 15, 2020)
The NRC is seeking a solution for a molecular assay allowing a rapid and efficient colorimetric detection of SARS-CoV-2 from saliva without the use of an instrument. The molecular assay will be integrated with saliva collection and processing technology developed by the NRC. The ultimate goal is the creation of a mass-producible, self-contained diagnostic test that will enable rapid identification of COVID-19 infection or immunity at point of care.
Up to 3 projects will be funded for up to $100K to the most promising proposals aiming to demonstrate proof of concept colorimetric detection of SARS-CoV-2 from saliva without the use of an instrument. The goal of this short-term project is to identify the most promising molecular assays. One or more project collaborators may subsequently be invited to submit a proposal for follow-on funding to support further assay maturation and production scale up, as well as the opportunity to work with the NRC research and development teams for its integration in a detection device that will be scaled up with the help of the Canadian industry.
Frequent, pervasive, and timely testing for COVID-19 infection and acquired immunity is key to shaping and directing responses to the current pandemic. While molecular-based detection of the virus is the mainstay of testing, its utility can be hampered by material shortages and delays introduced by centralized lab processing. The availability of a safe and effective diagnostic test, which could rapidly produce a simple result in home and point-of-care settings without need for instruments, would improve the timeliness of both clinical treatment and the public health data that informs adaptive public policies.
A novel solution is sought that can rapidly and accurately, without the need for traditional reagents and highly specialized equipment, detect the virus that causes COVID-19, a component of the virus, or an immune response of an individual recovered from COVID-19 disease. Such a device would facilitate diagnosis in diverse and remote settings, thereby enabling a broader response to the pandemic and its effects. The NRC has pioneered the development of a saliva collection and processing device that can be safely and easily used at home to collect and process saliva samples. The device will deliver a homogenized and filtered saliva sample, and may also perform mixing, filtering, and reagent storage as may be required to integrate with partner technologies. We are seeking both reagent and assay solutions that will be integrated to this saliva processing device in order to provide a sample-to-answer system capable of detecting SARS-CoV-2 or COVID-19 immune response within 30 minutes using only a simple visual result readout.
Desired outcomes and considerations
The solution must meet the following criteria:
- Demonstrate a method for reagent formulation and an instrumentless assay capable of detecting SARS-CoV-2 infection or immunity acquired against SARS-CoV-2
- Upon contact with the collected sample, and gentle mixing provided by the device, the assay should be able to complete without any external instruments or manipulation steps to arrive at a final solution
- Provide results within 30 minutes (at most) from sample collection to diagnosis.
- The sample input must be saliva
- The reagents formulation would need to be compatible with room-temperature storage for up to 6 months allowing for deployment in distributed testing sites
- The assay must be customizable for use in an instrument-free medical device sample-to-answer system—in particular formulation that can be stored in dry and/or liquid formats in polymer devices without loss of sensitivity and selectivity
- The assay must integrate and operate with a saliva collection and processing device developed by the NRC
- The results of the assay must be easily detectable by eye (e.g. colour change, striking by specific optical effects)
- The interpretation of the result should be easy for a lay person (i.e. negative or positive).
- The price of reagents should not exceed $20
- Potential for fabrication of up to 100,000 tests per month
Background and context
As of May 29, 2020, more than 5 million cases of COVID-19 have been reported globally, resulting in more than 350,000 reported deaths. Of this total, Canada has reported more than 80,000 cases and more than 6,000 deaths.
Public health and policy responses to the COVID-19 pandemic can be strengthened by the availability of timely results from frequent and pervasive diagnostic testing. Molecular-based detection of the SARS-CoV-2 virus, which is the mainstay of testing, presently requires the use of instruments which, due to being centralized in Canadian hospitals and diagnostic labs, can contribute to delays in the availability of results. Such limitations in timeliness and availability suggest that there is a significant opportunity to introduce a more rapid, front-line diagnostic test to enable earlier and more widespread detection of infections, asymptomatic carriers, and immunity. The benefits of such rapid detection and reporting could include timelier treatments, strengthened approaches for allocation of scarce public health resources, and adaptive public policies for containment and mitigation of broader pandemic impacts.
The selection of test site for the sample collection is important for obtaining reliable test results. Nasopharyngeal or oropharyngeal samples (NOS) are most commonly used at present for SARS-CoV-2 testing. However, this test method has been affected at times by supply chain shortages that limit availability of reagents and sample collection swabs. Moreover, the use of naso- and/or oropharynx swabs can be uncomfortable for patients, may pose infection risk to healthcare workers, and may be undesirable for self-sampling.
Recent work has demonstrated successful detection of SARS-CoV-2 in saliva specimens with efficacies that match those of nasopharyngeal or oropharyngeal samples. Saliva samples offer a number of advantages: they are less invasive and more convenient as compared to NOS or blood samples; they can be self-administered, thereby minimizing the risk of virus transmission to health care personnel; and, very importantly they can be performed in remote locations or homes. This potential use of saliva seems scientifically reasonable as it has been shown to contain live COVID-19 viruses (To K K-W, Tsang O T-Y, Yip C C-Y. et al. Clin Infect Dis 2020; ciaa149. doi:10.1093/cid/ciaa149), possibly containing a pool coming from the lower respiratory tract, nasopharynx and infected salivary glands. For some coronaviruses, infection of salivary glands occurs very early in the disease process. The content of salivary COVID-19 (viral load) has been shown to be highest during the first week after symptom onset (To K K-W, Tsang O T-Y, Leung W-S et al., Lancet Infect Dis 2020; S1473-). This emphasizes the role of saliva as a potential source of viral transmission and, as it could be detected in the saliva as long as 25 days after the onset of symptoms, suggests its potential use for monitoring viral clearance.
The NRC’s Pandemic Response Challenge Program searches to develop a novel approach to diagnostic testing that can rapidly (in less than 30 minutes) and accurately detect from saliva the virus, or a component of the virus, that causes COVID-19 in saliva without traditional reagents or reading instruments. Such a device can facilitate frontline diagnosis and care while expanding into non-traditional clinical environments or home settings. In order to achieve this ambitious goal, the program seeks research partners in academia and industry to contribute molecular assay solutions that can be integrated with the NRC device technologies and manufactured at scale.