Swabbing the nose with a rapid antigen test will not reliably detect the omicron variant in the first few days of an infection, so manufacturers should seek U.S. approval to allow users to safely collect samples from the throat as well, according to an infectious diseases expert.

The U.S. Food and Drug Administration has expressed concerns over the safety of self throat swabbing.

People can already transmit omicron to others when it has infected their throat and saliva but before the virus reaches their nose, so swabbing the nostrils too early in the course of infection will not pick it up, Dr. Michael Mina, formerly of the Harvard T.H. Chan School of Public Health and now chief science officer at eMed, said during a news conference on Thursday.