A group of Boston researchers have designed a postcard-sized test that can detect both a SARS-CoV-2 infection and the presence of antibodies as a result of recent infection—providing a two-in-one punch that can both diagnose active COVID cases (including specifying which variant is responsible), as well as how well protected someone might be from future infections, thanks to antibody levels. The researchers hope their new portable device, which tests a patient’s saliva sample within two hours, could be used as a valuable tool to help clamp down on spikes in new cases caused by the emergence of new variants over time. Preliminary findings from the device were published Monday in the journal Nature Biomedical Engineering.
“In the early days, everyone was working on developing diagnostics that could detect either the SARS-CoV-2 virus or antibodies against it, but not both,” said co-author Helena de Puig, a bioengineering researcher at Harvard’s Wyss Institute for Biologically Inspired Engineering, in a press release. This new test, she added, is all-in-one.
The test combines two existing COVID technologies developed by Wyss Institute researchers. The first, a variant-specific diagnostic test detailed last August in a paper published in Science Advances, looks for RNA common to all coronavirus variants as well as segments specific to each one. The other test measures COVID antibodies by sandwiching them between two probes that create an electrical signal.
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Using samples from 19 COVID-positive patients and 11 negative ones, the researchers found that their diagnostic was 100 percent accurate at detecting viral SARS-CoV-2 RNA and IgG antibodies produced in response to infection.
That’s encouraging news, but the researchers made it perfectly clear the results are hampered by the small number of saliva samples that were available to them. Nor is the device in its final form: Future tinkering could improve its electronics and make it reusable, rather than single-use.
“Being able to easily distinguish between different types of antibodies is hugely beneficial for determining whether patients’ immunity is due to vaccines versus infection, and tracking the strength of those different immunity levels over time,” said co-author Sanjay Sharma Timilsina, currently a lead scientist at biotech startup StataDX, in the press release.
The researchers see use for this test outside of COVID, too. The RNA- and antibody-sensing technologies could theoretically be applied to any flavors of those molecules, meaning we could be able to respond more quickly to future pandemics.
“What excites me about this diagnostic device is that it combines a high level of accuracy with a flexible design that could make it a major tool in our arsenal for addressing future pandemics,” co-author James Collins, an MIT bioengineering researcher, said in the press release.
