COVID 19 antibody test using saliva

Despite global efforts to determine human antibody levels, current IVD or ELISA strategies still don’t have sufficient sensitivity against SARS-CoV-2. Here we propose a novel assay, NEPPA to improve the sensitivity and reduce the overall cost for COVID-19 diagnostics. The assay can be used to test sera or saliva at an earlier time point compared to ELISA-based tests, potentially enabling city-wide at-home saliva tests. Our assay can also offer information on whether the antibody level in a patient is sufficient to provide protection from SARS-CoV-2.

SARS-CoV-2 originated from Wuhan, China in December of 2019 and has resulted in over 3.6 million confirmed cases and over 255 thousand fatalities globally. Because many infected individuals are asymptomatic, efforts to contain the virus have been less efficient and have made it difficult to determine the chain of transmission and perform subsequent contact tracing. It is also critical to determine the immune responses such as antibody levels to examine effective vaccination strategies against COVID-19. The current diagnostic strategy to determine COVID-19 infection is using PCR-based tests. It includes a series of highly labor-intensive processes that require significant training to perform. Combining the labor-intensity and the continuous increasing demand for tests, has led to an overwhelming burden for COVID-19 diagnostics. In addition to the PCR-based tests, antibody-based tests using IVD or ELISA have also been used widely. However, the lack of sensitivity using IVD or ELISA limits the use of these tests to only weeks after the symptom onset.

The Development of NEPPA with SARS-CoV-2 specific antigen: It has been recently shown that detecting antibodies in the spike protein from patient serum can be translated to antiviral immunity in patients. To explore this diagnostic strategy, we will first generate the carrier carrying the DNA sequence using SARS-CoV2 peptides and also express the same peptide on its surface. This strategy enables us to detect antibodies via the binding between the peptide and the antibody, but we can quantify this interaction using RT-PCR, which can provide 10x more sensitivity when compared to traditional ELISA. The format of this assay is designed as a reversed direct-ELISA, where the capture antibody were coated onto an ELISA plate to capture the antibody from human serum or saliva samples. The peptide carrier is then added and incubated at the last step. The carrier that remained intact after the washes will be chemically dissociated and subjected to RT-PCR using specific primers. Using peptide carriers can also significantly reduce the cost each sample since no protein purification is required. 

Unique advantages of NEPPA diagnostic strategy is that it can provide higher sensitivity and more accurate level of protection against COVID-19. It can be scaled to evaluate any population from their home.

•10x more sensitivity when compared to COVID19 ELISA or IVD approach
•Enabling at-home saliva tests
•Less than $0.5 test/person (compared to $6-12 test/person using commercial COVID19 ELISA kit).
•Able to provide workers more accurate “back-to-work” status against SARS-CoV-2.

The current IVD or ELISA strategies still don’t have sufficient sensitivity against SARS-CoV-2. Especially when testing antibody levels using highly diluted samples such as human saliva. The reliance of using sera is highly inefficient and can be difficult to test large populations. Our assay can improve sensitivity and reduce the overall cost for diagnostics. The assay can be used to test saliva, after infection or vaccination, potentially enabling city-wide at-home tests, which aligns with challenge by providing both short and long term solutions to the current COVID 19 pandemic.

How many people does your solution currently serve? 

0

How many will it serve in one year? 

Potentially 1000+/day/machine

There are three phases for this project. Phase 1: is to prototype and optimize the assay, it will require two additional full-time scientist to complete, all current lab equipment are sufficient. Phase 2: is to customize the diagnostic system by using automated systems, which will require the purchase of additional machineries. Phase 3: is to scale up, depending on the needs and the availabilities of the supply chain, a single set of machine can test ~1000 samples per day. 

Although we will have a strong scientific advisors, we have limited exposure to the potential laws, finances and operational issues that may arise through this operation.

We plan to work with industry leaders to solve these issues.

I have been studying virology, epidemiology and building in-house ELISAs for viral diagnosis for many years. I have contributed scientific findings including diagnostics assay, therapeutics and vaccines to several recent outbreaks including Influenza and Zika viruses. Since the early January 2020, our lab has conducted comprehensive bioinformatics analyses to track inheritable mutations and the divergence of SARS-CoV-2 from its related coronaviruses. Further studies using SARS-CoV-2 peptides demonstrated that serum samples from patients infected with SARS-CoV-2 containing antibodies can be directly linked to overall disease severity and fatality.

I have also worked at local COVID-19 diagnostic centers. Where I help to 1) developed the SOPs and trained scientists for handling human serum and saliva samples; 2) determined guidelines for deactivating SARS-CoV-2; 3) setup laboratory spaces for effectively test specimen in a BSL2+ setting; 4) determined the effectiveness of all commercialized ELISA kits; 5) developed novel in-house ELISA systems to effectively determine antibody levels in serum and saliva; 6) provided protocols to potentially scale up a test using automated systems. After a few weeks of efforts, I completed the testing for three distinct in-house ELISAs for potential scaling-up. More importantly, these kits can be used to detect antibody levels from serum, at 3-5 weeks from patient’s symptom onset. These works have provided me with first-hand experience with COVID-19 diagnostics, and how to effectively manage a team of scientists to communicate, optimize and scale novel testing strategies.

The Elevate Prize can provides us with continuous financial support, which is valuable to actualize our goal of testing for COVID19 to the mass.