Will rapid COVID tests detect new variants?

New research is assessing how quickly tests can perform when faced with future variants of SARS-CoV-2.

The availability of rapid antigen tests has led to a significant advance in efforts to contain the spread of COVID-19. But each new type of concern raises questions about whether diagnostic tests will still be effective.

The new study in cell He tries to answer these questions.

Researchers have developed a new method for assessing how mutations SARS-CoV-2 can affect the recognition of antibodies used in rapid antigen tests.

Since most rapid antigen tests detect the SARS-CoV-2 nucleocapsid protein (N protein), the team directly measured how mutations in the N protein affected the diagnostic antibodies’ ability to Get to know their target.

“Based on our findings, none of the previous and current major variants of SARS-CoV-2 contain mutations that would affect the ability of current rapid antigen tests to detect antibodies,” says first author Philip Frank, associate professor at Department of Biochemistry at Emory University. “Moreover, this data allows us to look a step further and predict test performance against almost any variable that may arise.”

The study used a method called deep mutational scanning to assess all potential mutations in protein N in a single high-throughput experiment. The researchers then measured the effect of the mutations on their interaction with antibodies used in 11 commercially available rapid antigen tests and identified mutations that might allow the antibodies to escape.

Says senior study author Eric Orlund, professor in the Department of Biochemistry. “The results shown here could allow us to quickly adapt to the virus as new variants keep appearingrepresenting an immediate impact on clinical and public health.”

The results show that it is relatively rare for variants to have N-protein mutations that allow them to evade diagnostic tests, but that there is a small percentage of sequences that can affect detection. Researchers, public health officials, and test manufacturers can use this data to determine whether a diagnostic test needs to be evaluated for its ability to detect these mutations or to inform future test design.

“Considering the endless cycle Of the new variables, the data from this study will be useful for years to come,” says Bruce J. Tromberg, MD, director of the National Institute of Biomedical Imaging and Bioengineering (NIBIB) and leader of the Rapid Technology Accelerator for Diagnostics (RADx) Program at the National Institutes of Health.

While many variants of concern harbor multiple N-protein mutations, the study authors note that their method does not assess how multiple mutations might affect diagnostic antibody recognition, which is a limitation of the study.

Support for the project came from NIBIB as part of the RADx initiative.

source: Emory University