Small U.S study raises doubts about rapid Covid tests’ reliability in early days after infection

Study raises doubts about rapid Covid tests’ reliability in early days after infection A new study raises significant doubts about whether at-home rapid antigen tests can detect the Omicron variant before infected people can transmit the virus to others. Matthew Herper STAT

A new study raises significant doubts about whether at-home rapid antigen tests can detect the Omicron variant before infected people can transmit the virus to others.

The study looks at 30 people from settings including Broadway theaters and offices in New York and San Francisco where some workers were not only being tested daily but were, because of rules at their workplaces, receiving both the antigen tests and a daily test that used the polymerase chain reaction, or PCR, which is believed to be more reliable.

On days 0 and 1 following a positive PCR test, all of the antigen tests used produced false-negative results, even though in 28 of the 30 cases, levels of virus detected by the PCR test were high enough to infect other people. In four cases, researchers were able to confirm that infected people transmitted the virus to others during the period before they had a positive result on the rapid antigen test. ...