Umatilla County is in the middle of one of the worst outbreaks of COVID-19 in Oregon. Since the beginning of July, the county has registered more than 17 cases per 1,000 people. But data released Friday by Oregon State University suggest the rate of coronavirus infection could actually be significantly higher in places.
A door-to-door testing initiative called TRACE (Team-based Rapid Assessment of Community-Level Coronavirus Epidemics) in Hermiston found that nearly 17% of the city’s population is infected. That’s 169 infections per 1000 people in the city.
Project co-director Ben Dalziel calls the infection numbers “very high,” the highest yet detected by TRACE after testing in several cities around the state.
“It’s not only high prevalence, but it’s widely distributed. And a majority of the participants who tested positive did not report symptoms. So widespread and largely asymptomatic,” Dalziel said.
Of those infected, 80% did not show symptoms of COVID-19. The door-to-door testing was conducted Sunday.
This kind of community-wide testing has an advantage over the traditional ways the state and local health agencies are tracking the virus. Statewide testing is still largely focused on individuals who display symptoms of COVID-19.
“By doing a random sample, we get a representative estimate across both asymptomatic and symptomatic individuals regardless of whether or not they’ve had access to a test. So it provides a different type of information than the case-count data or hospitalization data,” he said.
On Thursday, Gov. Kate Brown ordered the county to re-institute the restrictions on non-essential businesses and public gatherings that the rest of the state lived under early in the pandemic.
“If we do not act immediately, we could see the virus spread even more rapidly, infecting and killing more community members,” Brown said in a statement.
The results from the TRACE testing are being bolstered by another coronavirus detection initiative out of Oregon State University that quantifies the amount of the virus present in wastewater to get an even broader sense of how prevalent the virus is in a community. Researchers analyzed samples of wastewater collected at different sewer locations around Hermiston.
“Looking throughout the community, it appeared to be pretty widespread. We didn’t find isolated hot spots. Every location we sampled, we found virus signatures,” said Tyler Radniecki. “The concentrations we were seeing (in Hermiston) are the highest we’ve seen so far in the state.”
Both OSU programs were invited in to sample by local health officials and the state during a known upswing in COVID-19 cases. But both TRACE and the sewer surveillance programs have the potential to be even more helpful if deployed as the outbreak wanes.
“TRACE essentially had bad news to share (this time around). We’re just the messengers. We just report what’s happening ... but we can also provide, when prevalence is lower and we’re able to ascertain that, it can help counties make the decision to reopen at the appropriate time,” Dalziel said.
The sewer testing also has the potential to detect the beginnings of an outbreak in a community before cases are identified by health officials. Radniecki says his program has a new agreement with OHA to begin weekly coronavirus monitoring at wastewater treatment plans in 45 different Oregon communities. That surveillance will continue for 2.5 years.
