The COVID-19 test using a nasal swab or antigen swab is claimed to be unable to detect the Omicron variant in the first few days of infection, according to new research in the United States (US).
According to infectious disease experts in the US, to accurately detect the Omicron virus, it is advisable to carry out a swab test that also takes a sample from the throat.
"People can transmit Omicron to other people when it has infected their throat and saliva, before the virus reaches their nose. So a nostril swab test too early in the infection process will not detect it," said Dr Michael Mina of the Harvard TH Chan School of Public Health. and Chief Science Officer at eMed, quoted from Reuters, Monday (10/1/2022).
A study Wednesday (5/1) in medRxiv looked at 29 Omicron-infected workers in high-risk professions who performed PCR and antigen tests simultaneously over several days. This test proves that people infected with Omicron will take longer to detect using an antigen test than a PCR test.
So, when an Omicron patient is tested using an antigen the result can be negative. However, he turns out to have or still has the virus in his body.
"When people test negative with rapid swab antigen, they can still have a highly contagious viral load and pass it on to other people," said study leader Blythe Adamson of the New York-based risk reduction firm Infectious Economics LLC.
Research shows that COVID-19 symptoms appear earlier with Omicron than with other variants.
"When you feel symptoms, assume you are positive, but if you want to use an antigen swab test, wait until a few days have passed," advises Mina.
