Companies Ditch Plans for Rapid Coronavirus Spit Tests at Home

You won’t be buying a rapid spit test anytime soon. But nose-swab versions might be on the way.


By Katherine J. Wu

For months, public health experts have been eagerly watching the companies developing spit tests for the coronavirus that could be used at home, producing results in a matter of minutes.

If these rapid saliva tests worked, as many news articles have pointed out, they could greatly expand the number of people getting tested. Some experts have even said they could perform as well as a vaccine in curbing the spread of the coronavirus and paving a path back to normalcy.

But so far, the technology is not panning out as some have hoped.

E25Bio and OraSure, two companies pursuing rapid at-home coronavirus tests, have abandoned efforts to use saliva in their products. Their tests, which detect pieces of coronavirus proteins called antigens, will for now rely on shallow nose swabs instead.

“If I was placing a bet — which I am, because I’m leading an antigen-based testing company — I would say it’s going to be very difficult for antigen-based testing to work on saliva samples,” said Bobby Brooke Herrera, an E25Bio founder and its chief executive. The notion that the virus sets up shop in the mouth and produces enough antigen to be picked up by today’s technology, he said, “is far-fetched.”

The two companies pursued saliva (or “oral fluids,” in the case of OraSure) for months in the hopes of their tests being more comfortable than swabs, some of which go painfully deep into the nose, and less reliant on sputtering supply chains that have caused long delays for laboratory tests.

“There’s nothing more convenient than spitting in a tube,” said Dr. Valerie Fitzhugh, a pathologist at Rutgers University.

But as they continued to tinker with their tests, researchers at both E25Bio and OraSure found saliva’s performance to be more lackluster than anticipated, and were forced to pivot.

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