The two-week infection rate for COVID-19 is calculated from the point at which a positive sample is drawn, not the date on which a case was reported to the public, Clallam County Health Officer Dr. Allison Unthank said.
Clallam County’s 53.9 per 100,000 population infection rate was derived from samples collected from July 26 through Sunday, Unthank said Tuesday.
“They standardize by the date the lab was drawn,” Unthank said, “because if you look across Clallam County, most of our labs come back within about two days, but in the far West End, sometimes it’s like seven days.”
“So in order to keep a consistent metric, it’s when the lab was done is what we measure by,” she said.
Jefferson County had a 15.7 per 100,000 infection rate based on having five new cases in the past 14 days, Jefferson County Health Officer Tom Locke said.
The statewide COVID-19 transmission rate was 127.6 per 100,000 for the two-week period ending Aug. 4.
As of Tuesday, the state COVID-19 risk assessment dashboard listed 30.3 cases per 100,000 in Clallam County for the past two weeks.
Unthank said the disparity comes from the state using older data — 30.3 per 100,000 was Clallam County’s infection rate for the two-week period ending Aug. 4.
To find the new data, click on the “COVID-19 Disease Activity,” tab on the dashboard, click on Clallam County and use the mouse to hover the over the line graph.
“We use an adjusted population of 77,000, so the formula is that total number of reported cases who had labs drawn in that time period divided by 0.77,” Unthank said.
“It won’t always match the total number (of cases) reported.”
Clallam County had 47 new cases of COVID-19 reported for the two-week period ending Tuesday — 89 as of July 28 and 136 as of Tuesday.
That equates to 61 cases per 100,000 without the formula that is applied.
Jefferson County had five new cases for the two-week period ending Tuesday — 50 as of July 28 and 55 as of Tuesday.
That equates to 15.7 per 100,000 population based on Jefferson County’s 31,900 population in 2019.
“We were using the 2020 county population of 32,800 last week but switched to the 2019 population of 31,900 to be consistent with the state calculations,” Locke said Tuesday.
A rate below 25 per 100,000 is considered low risk, according to a measurement provided from the state last week. Between 25 and 75 cases per 100,000 is moderate risk. High risk is over 75 per 100,00, as computed by the formula.
Gov. Jay Inslee and other officials announced the infection risk parameters when recommending that most schools consider online learning only this fall to slow the spread of COVID-19.
In moderate-risk counties, he said distance learning should be considered for middle and high school students. In-person learning could be an option for elementary students and those with special needs.
In low-risk counties, school districts should consider a hybrid distance/in-person schedule for older students and in-person learning for elementary school students.
Unthank said a data malfunction at the state level caused a lag in COVID-19 cases appearing on the dashboard.
“I’m hoping once they get that fixed, they’ll start updating it daily again, and then we’ll be able to see our numbers in real time,” Unthank said.
“In order to keep a consistent metric,” she added, “it’s when the lab was done.”
Reporter Rob Ollikainen can be reached at [email protected].