Public Willingness Key In Coronavirus Contact Tracing: Study

SEATTLE, WA — Health officials are touting a new study from the Institute of Disease Modeling which shows that a combination of increased coronavirus testing, effective contact tracing, isolation and quarantine could help the state recover and reopen as the coronavirus pandemic wanes. But the model also warns: the state must remain cautious as it reopens those businesses, or risk a spike in new infections and deaths.

The Institute of Disease Modeling is a Bellevue-based research group that has been studying the coronavirus since the early stages of the outbreak. Their new model is called "Covasim" a contraction of COVID-19 and simulation, because it simulates how individual humans interact and spread the virus to each other.

After applying the model to King County, researchers say there are two key findings that the Covasim model shows. First, social distancing and other safety measures in King County have cut the transmission potential of the coronavirus to about a third of what it was when the epidemic was in the early stages. Health officials say that's in large part because the community has done well following social distancing regulations.

“Our community’s initial compliance with the stay at home directive and other COVID-19 precautions such as physical distancing, avoiding non-essential activities and large gatherings and good hand hygiene has greatly reduced the spread of COVID-19 in King County,” said Dr. Jeff Duchin, Health Officer for Seattle & King County.

The second part of Covasim's findings are less optimistic, showing that reopening Washington's businesses could cause the current transmission rate to double, back to around 70% of what it was in the early stages of the pandemic, unless it is mitigated by effective contact tracing programs.

Researches say that increase could be counter-balanced if three conditions are met:

• Coronavirus testing doubles.
• Contact tracers can effectively quarantine 70 percent of workplaces that have been exposed to the virus within 48 hours of a confirmed case.
• 90 percent of households with a coronavirus patient follow guidelines correctly and enter isolation.

Health officials say the first goal is within reach. At a press conference Tuesday, Duchin said that King County has been able to provide more testing opportunities than there is current demand for tests, and that testing could be doubled if more members of the community step forward to take coronavirus tests. The other two conditions could prove more difficult, and all three will require the public's cooperation.

“To move forward while decreasing risk sufficiently, we need to diagnose people with COVID-19 earlier in the course of illness and ensure that infected people are safely and rapidly isolated from others," said Duchin. "We also need to ensure that the household members and other close contacts of COVID-19 cases are rapidly identified and quarantined."

Washington state first announced the contact tracing program in mid-May. The program works by having volunteers interview confirmed coronavirus carriers, then placing their households in isolation. Tracers then try to identify every person that coronavirus patient may have exposed the virus to, and encourage them to enter quarantine so they don't spread the virus further. Washington significantly expanded the scope of the program a week after it was first announced.

Find the full study on the Covasim model here.