Drive by the Teton County Fairgrounds and you might notice a pair of tents next to the green metal Exhibit Hall. The temporary set-up houses Teton County Health Department’s surveillance testing program for COVID-19.
Asymptomatic carriers of SARS-CoV-2, the virus that causes COVID-19, have been well documented, with the Centers for Disease Control and Prevention estimating that up to 40% of people might show no symptoms. A majority of people who do show symptoms will have a mild case, meaning they also might not realize they have the disease.
For those people, many of whom are younger, COVID-19 could end up being a mere inconvenience, if they notice it at all. However, they could be vectors that spread the virus to more vulnerable populations.
“First you see the spike in younger adults, then you see that spike distributing across the age spectrum, then you see hospitalization rates increase, then you see deaths increase,” Teton District Health Officer Dr. Travis Riddell said at the July 10 community update.
Surveillance testing is meant to catch asymptomatic cases before they begin that domino effect, and the Health Department hopes to test 1,000 people a week by the end of the month. Businesses sign up, then employees can elect to be tested using a cheek swab test, rather than the invasive nasopharyngeal swab that must be inserted deep into the nasal cavity.
Federal stimulus money covers the testing, so it is free for both employers and workers. Anyone who wants can opt out of being tested.
Public health coordinator Rachael Wheeler said Tuesday that 1,194 people were tested in the last three weeks, with nine being positive. That’s a 0.75% asymptomatic positivity rate, but that doesn’t necessarily indicate that the community as a whole has the same level of asymptomatic carriers.
Some people are what is referred to as “presymptomatic,” meaning they start showing symptoms after testing.
“So I think it will be really hard to extrapolate” about communitywide asymptomatic spread, Wheeler said.
Just like COVID-19-positive people who are tested at a clinic because they started having symptoms, a case turned up by surveillance testing initiates a 10-day self-isolation period and a contact tracing investigation.
Those found through surveillance testing might have eventually started showing symptoms and gone in for testing on their own. However, by finding them when they are asymptomatic or presymptomatic, officials hope to limit the number of community members an infected person might interact with.