Rapid nasal COVID tests feared to be returning false negatives – Axios

There appears to be yet another layer to America's coronavirus testing chaos: People may not test positive on rapid nasal tests until after they're infectious, which would make the tests an unreliable measure of whether it's safe to gather.

The big picture: Rapid tests have been hailed as a way to weather the Omicron surge without mass disruption to everyday life. But they've been in short supply for weeks, and now new research along with loads of anecdotal evidence suggests there may be significant limitations to their usefulness with this variant.

Driving the news: A small preprint study released Wednesday found that, among a case study of 30 people who took nasal rapid antigen tests and saliva PCR tests at the same time, four of them transmitted the virus following a false negative rapid antigen test.

State of play: The study builds on emerging evidence that saliva swabs may be better for detecting Omicron than nasal swabs.

Our thought bubble: Almost everyone I talk to professionally or personally knows someone who tested negative on a rapid antigen test but positive on a PCR test (the gold standard), or who tested negative on rapid tests while symptomatic for days before getting a positive test, or who attended a gathering where someone had a negative rapid test ahead of time but went on to infect others with COVID.

What they're saying: "We have seen far too many people who are clinically ill who are in their third and fourth day of negative antigen tests but test positive by PCR," said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.

The bottom line: If you can get ahold of a rapid test, and you test negative on it, that may still not mean it's safe to visit your elderly grandparents or that you can go to work without worrying about spreading the virus.

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Rapid nasal COVID tests feared to be returning false negatives - Axios