UW Health: Omicron exposure takes seconds, addresses nose vs. throat testing

MILWAUKEE, Wis. (CBS 58) - This week, the United States FDA cautioned against using at-home COVID-19 tests to collect samples from the throat instead of a nasal sample, as the tests instruct. 

"FACT: When it comes to at-home rapid antigen #COVID19 tests, those swabs are for your nose and not your throat," it said Friday on Twitter. 

CBS 58 spoke with Dr. Jeffrey Pothof, Chief Quality Officer, at UW Health about the matter. 

"I think where this comes from is there are some small studies, omicron hasn't been out there that long, that suggest that higher concentrations of omicron can be found in the oral pharynx which would suggest the spit might have viral concentrations that are higher before you see it in the nose or the nasal pharynx. 

Pothof says anyone taking an at-home COVID test has to be careful in the way they take the sample. 


"A lot of these tests, the way they design them are for a very specific collection process. What sometimes starts to go awry when we do an alternate collection process is sensitivity and specificity," said Pothof.

He says that using a nasal test kit for a throat swab, could provide a higher rate of a false positive or a false negative. 

"We switched from nasopharyngeal swabs to saliva for folks that were going to undergo surgery. We do something called validation and that has not yet been done on the rapid tests, taking an oral sample. What you want to do is take your best test which is nasal PCR pharyngeal and say you'd test 30 people and say we know 20 of them are positive, when we test them with a rapid test and we use the mouth are 20 of those positive? We can kind of prove to ourselves how good this alternate test process works compared to the gold standard," said Pothof. 

He went on to say he believes if the data holds that manufacturers could create a new test for an oral swab but for now, they simply don't have the data. 

When the pandemic began, the CDC said COVID exposure was considered as 15 minutes or more less than six-feet away from someone infected with the virus. Health experts at UW Health say omicron doesn't follow that rule. 

"It was under 15 minutes you were unlikely to get infected but I don't think that message has necessarily been updated as we've had more contagious variants so like 15 Minutes is no longer at all pertinent. Right now, with omicron we don't measure contact times in minutes it's in seconds. If you're around someone for 10-30 seconds who has omicron you're exposed enough to get infected," explained Pothof. 

It's an infection people continue to be tested for at Hayat Pharmacy. Some, unsure what to think about omicron. 

"It's not necessarily fearful but I've heard that this variant isn't as bad as the others more like a common flu," said Laquon Triplett. 

But doctors want to clarify, omicron isn't to be taken lightly, even if it is considered a less severe form of COVID. 

"It's so contagious. So, instead of 100 people 1000 people are now infected. So, now it doesn't matter that as a percentage it sends less people to the hospital the huge denominator, the huge number of people is actually driving hospitalizations up," said Triplett.  

Hospitalizations doctors say you can prevent by wearing a mask, being vaccinated and getting tested to keep others safe. 

"Everybody has their own perspective on things but it's always good to know especially if you're going to be around a lot of people just to get tested just to make sure you're not spreading it more than it already is," said Triplett.   

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