Rapid antigen tests are failing to detect the first few days of COVID-19 infections, a period when people are already capable of transmitting the virus, according to a prominent German virologist.
The shortcoming could undermine efforts to use these fast and cheap tests, already widely deployed across Germany, the U.K. and the U.S., to determine if someone can safely enter a place where people are congregating, Christian Drosten, head of the virology department at Berlin’s Charite hospital, said on a podcast.
It will probably take months before this phenomenon is backed up by clinical data in scientific journals, he said. That’s because, for now, few people who believe they are healthy are subjecting themselves on the same day to both a rapid antigen test and a molecular test, such as one based on the reverse transcription polymerase chain reaction (PCR) method, the gold standard for accuracy.