Several rapid antigen tests that are widely used in the United States — Abbott BinaxNow, BD Veritor At-Home and Quidel QuickVue — are effective in detecting the Omicron variant of the coronavirus, according to a new real-world study that eases concerns about possible false negative test results.
The results of the tests for Omicron and Delta variants were similar. However, the study was not published in a peer-reviewed journal. People who tested positive for the virus using a P.C.R. According to the research, which was a collaboration between the National Institutes of Health and UMass Chan Medical School, 61% of Omicron patients also tested positive for the virus within 48 hours. This compares with 46 percent of Delta patients. The statistical differences between variants were not significant.
The tests performed better for people with high viral loads. They detected more than 90% of Omicron and Delta infections in these individuals, the researchers discovered.
“This study adds to the body of evidence that says that Omicron can be detected with the home tests that we have,” said Nathaniel Hafer, a molecular biologist at the UMass medical school and an author of the study.
These rapid antigen tests are less sensitive that P.C.R. These tests detect proteins on the virus’ surface. If genetic mutations alter these proteins, it could affect the tests’ ability to detect the virus. Researchers must reevaluate the tests each time a new variant is discovered.
Early laboratory research suggested that antigen tests might be less sensitive than the previous variants to detect Omicron, which could mean that they might produce more false positives. F.D.A. The F.D.A. warned about this possibility in December.
Experts had pointed out that the tests needed to be evaluated in large-scale, real-world studies.
These findings are part an ongoing U.S. study which began in October. It aims to evaluate the performance and safety of rapid antigen tests in symptomatic individuals.
Participants were provided with P.C.R. Home-collection kits were provided, as well as one of three randomly chosen brands of rapid blood tests. They collected P.C.R. They took samples and ran rapid antigen tests every two hours for 15 days. They sent their P.C.R. They sent their P.C.R. samples to a laboratory for testing and reported the results in a research application. (They were also asked if they wanted to upload photos of the rapid-test results.
Between October and January, almost 6,000 people took part in the study. The new analysis is focused on 153 people who tested positive to the virus at least once during a P.C.R. a test at some time during that period. The researchers concluded that approximately sixty percent of the cases were confirmed or probable Omicron infections. They used a combination sequencing data and information about the date each person tested positive. The rest were believed to have Delta.
The P.C.R. The results showed that approximately half of the 153 participants had high viral loads. This group included 96 percent Omicron and 91 per cent of Delta infection patients. They both tested positive for antigens within two days of their positive P.C.R. result.
“The study showed that when there’s higher amounts of the virus, these antigen tests are going to do a good job in detecting cases,” said Matthew Binnicker, the director of clinical virology at Mayo Clinic, who was not involved in the research. “The real concern of false negatives is when there’s lower levels of the virus.”
Experts advise people who have symptoms of the virus or have been exposed to it to undergo multiple antigen testing over a few days to increase their chances for detecting the infection.
Source: NY Times