Kathimerini Greece Newsroom
The rapid coronavirus antigen tests, which have the great advantage of being effective within minutes, are less sensitive to the Omicron mutation than previous ones, US health officials warned on Tuesday.
This means that tests of this kind may give false-negative results, even if someone is infected with the new variant.
Antigen tests look for antigens on the surface of the virus; molecular tests look for its genetic material. The former was already less sensitive than the latter.
"Preliminary data suggest that antigen tests do detect the Omicron variant, but have reduced sensitivity," said a statement from the US Federal Drug Administration (FDA).
However, the FDA noted that it is important to continue their recommended use within the correct guidelines. "If a person gets a negative result after an antigen test, but there are suspicions that he is infected (…), for example, if he has symptoms (of COVID-19) or a high probability of infection due to exposure, it is important to do a molecular test (PCR test)".
Antigen tests look for antigens on the surface of the virus; molecular tests look for its genetic material. The former was already less sensitive than the latter, the FDA recalled.
The sensitivity of these tests is further reduced due to the multiple mutations of the Omicron variant. However, rapid tests are considered useful by experts in general, as they can often be done at home, at low cost, helping to control the pandemic.
In the US, home screening kits, which are becoming increasingly popular, are now running out, in part due to the rapid rise in infections attributed mainly to Omicron and in part due to the end-of-year holidays.
Last week, President Joe Biden announced the purchase of 500 million quick home tests. Americans will be able to order them through a special website that will be operational from January.
