Blogs: The Official Team behind ASU's COVID-19 Saliva Test

Within the first few days of 2020, the World Health Organization announced a new coronavirus-related virus that originated the previous month in Wuhan, China.¹ In the same month, a Washington resident was diagnosed with the first case of COVID-19 in the United States. By the end of January, WHO issued a public health emergency, which the US followed shortly after announcing the public health emergency on Feb. 3, 2020. Nearly two months after the first confirmed case of COVID-19 in China, WHO declared the COVID-19 outbreak a pandemic.²

However, months before the official declaration, Arizona State University's President Michael M. Crow started discussing the need for a quick, accurate COVID-19 test with ASU Biodesign Clinical Testing Lab (ABCTL) members, including Joshua LaBaer and Dr. Vel Murugan, about the possible need for a COVID-19 test. By March 2020, when the WHO declared the COVID-19 outbreak a pandemic, ABCTL created a saliva test and started taking samples from ASU students.

The need to develop a new diagnostic test for COVID-19 took priority in ASU Biodesign facilities, which are overseen by LaBaer. It led to recruiting other research centers within Biodesign, such as the DNASU Plasmid Repository. DNASU Plasmid Repository receives, grows, stores, and distributes plasmid clones and collections, providing the ABCTL with tools to advance research into the human proteome. With an all-hands-on-deck approach, DNASU provided tools and expertise to help create a new test as concerns of a pandemic rose. Joining the effort, the DNASU team "developed a set of clones of every coronavirus and some of the mutants," Mitch Magee, a DNASU researcher, explained. Each of these plasmids holds a single gene of coronavirus, which will provide human cells necessary information to initiate the production of coronavirus proteins and prompt an immune response against the virus.³

Following the development of these plasmids, the team tested over 3,000 ASU students to assess their ability to recognize coronavirus. Within a month of the COVID-19 test development and testing, "we were registered with the clinical testing services...and at the peak, we were doing over 20,000 tests a day," Magee said

The team created a polymerase chain reaction (PCR) test for COVID-19. These tests require a sample of the testes's nasal swab, nasopharyngeal swab, or saliva.⁴ With this material, the test detects genetic material from the coronavirus by amplifying "small amounts of RNA from specimens into deoxyribonucleic acid (DNA), which is replicated until SARS-CoV-2 is detectable if present" (PCR Test for COVID-19: What It Is, How Its Done, What The Results Mean, 2021).

This type of test reflects similarly to the loop-mediated amplification reaction (LAMP) test, which also works by detecting genetic material from the coronavirus, however, only through a nasal swab sample.⁵ Therefore, the PCR test offers scientists, doctors, and patients the gold standard test for diagnosing COVID-19. But how does the test identify this genetic material when it continues to mutate?

Everyone has become aware that SARS-CoV-2 mutates easily, leading to new variations,including the Delta and Omicron variants. These mutations occur when the virus replicates and experiences random "copying errors," resulting in genetic variation among viruses. However, despite its ability to mutate, the SARS-CoV-2 virus mutates four times slower than seasonal flu.⁶

Despite the slowed mutation rate, plasmids played an essential role in creating and maintaining the success of ASU's saliva-based COVID-19 test due to the virus's likelihood to mutate. The availability of diverse plasmids containing coronavirus genes, including mutants, enabled the test to identify multiple sections of the SARS-CoV-2 genome.⁷ This adaptability ensured the test's continued accuracy, even in the face of new variants such as the Delta and Omicron variants. As a result, the test retains its effectiveness, can detect emerging variants, and provides accurate results.