A low-cost CRISPR-based paper-strip test distinguishes between influenza types and can be reprogrammed to recognise different viruses including H5N1 bird influenza. A recently published paper describes the development of the new test that could allow more patients to find out which type of influenza they have and get the right treatment.
The test, developed by a team from the Broad Institute of MIT and Harvard and Princeton University, and supported by the US Centers for Disease Control and Prevention, uses CRISPR to distinguish between the two main types of seasonal influenza (A and B), as well as seasonal subtypes H1N1 and H3N2. It can also identify strains that resist antiviral treatment, and with further work, could potentially detect swine and avian strains, including H5N1, which is currently infecting cattle.
Appearing in The Journal of Molecular Diagnostics, the results could help improve outbreak response and clinical care by bringing tests that are accurate, low-cost, and fast to doctors’ offices and laboratories across the US and in other countries.
“Ultimately, we hope these tests will be as simple as rapid antigen tests, and they’ll still have the specificity and performance of a nucleic acid test that would normally be done in a laboratory setting,” said Cameron Myhrvold, co-senior author on the study along with Pardis Sabeti, an institute member at the Broad and a professor at Harvard University and the Harvard T.H. Chan School of Public Health, as well as a Howard Hughes Medical Institute investigator.
The test is based on a technology called SHINE, which was developed by Sabeti’s laboratory in 2020 and uses CRISPR enzymes to identify specific sequences of viral RNA in samples. The researchers first used SHINE to test for SARS-CoV-2, and later to distinguish between the Delta and Omicron variants. Then, in 2022, they began adapting the assay to detect other viruses they knew were always circulating: influenzas. They wanted to create tests that could be used at the point of care rather than hospitals or diagnostic laboratories with expensive equipment.
Typical diagnostic approaches such as polymerase chain reaction (PCR) require lengthy processing times, trained personnel, specialised equipment, and freezers to store reagents at -80°C, whereas SHINE can be conducted at room temperature in about 90 minutes. Currently, the assay only requires an inexpensive heat block to warm the reaction, and the researchers are working to streamline the process with the goal of returning results in 15 minutes.
The researchers also adapted SHINE to distinguish between different flu strains. In the future, they say the assay could be adapted to detect two different viruses with similar symptoms, such as influenza and SARS-CoV-2.
- Zhang YB, Arizti-Sanz J et al. CRISPR-based assays for point of need detection and subtyping of influenza. J Mol Diagn. 2024 Jul;26(7):599-612.. doi:10.1016/j.jmoldx.2024.04.004.