- Rapid antigen tests, which can be performed at home to check for COVID-19 infection, may not be keeping up with developing SARS-CoV-2 strain variants.
According to a recent study, rapid antigen tests, which may be used at home to check for COVID-19 infection, may not be keeping up with evolving variants of concern that differ from the initial SARS-CoV-2 strain.
Students from Harvard T.H. Chan School of Public Health and Beth Israel Deaconess Medical Centre (BIDMC) discovered that some fast antigen testing might be ineffective at detecting distinct COVID-19 variations.
While quick antigen testing is still useful for detecting COVID-19 infections, the study’s findings suggest that these tests will need to be “continuously assessed” and updated to account for virus variations.
The results were issued in the Journal of Clinical Microbiology on Thursday.
The biggest problem with quick testing, according to scientists, is that they were created using the original SARS-CoV-2 virus strain, which surfaced late in 2019. Since then, the virus has evolved countless times, and several dangerous viral strains have appeared.
In a news release, co-corresponding study author and BIDMC clinical director James Kirby remarked, “Unlike sensitive molecular tests that detect numerous SARS-CoV-2 genes, fast antigen testing target a single viral protein.” “However, as the pandemic progresses, some speculate that the performance of available antigen tests may differ across the COVID types of concern.”
Using live virus culture strains, the researchers evaluated how effectively four commercially available fast antigen tests could detect two COVID variants of concern — the highly infectious Delta and Omicron variants.
The researchers compared the variations in the Binax, CareStart, GenBody, and LumiraDx fast tests’ detection limits, which is the least amount of viral antigen detectable with 95% certainty.
In all four experiments, researchers discovered that the Omicron version was just as sensitive as the original SARS-CoV-2 strain. Only the CareStart test revealed “equal detection” of Omicron, Delta, and the original virus, whereas three of the four tests showed poorer sensitivity to the Delta strain.
Given the discrepancies in the tests’ detection thresholds, Kirby, a professor at Harvard Medical School, believes cases may have been missed during the pandemic’s last two waves.
“We believe that the observed decrease in Delta sensitivity resulted in a 20% or more loss of detection in potentially infectious persons – nonetheless, the most infectious individuals should have been caught,” Kirby said.
“However, our findings imply that antigen test performance for evolving variants should be re-evaluated to ensure that they continue to achieve the pandemic’s intended public health testing purposes,” he added.
Experts have previously urged Canadians to undergo two rapid tests to confirm whether or not they are infected due to the unclear sensitivity of rapid tests regarding COVID-19 variations.
Source: CTV News