These graphs show when the coronavirus peaked in Ada, Blaine and Canyon counties
Most data tracking for Idaho’s battle with the coronavirus has focused on the rise and fall in new confirmed cases, which was the best number publicly available.
Earlier this week, Blaine County released a better representation of the progress of the COVID-19 disease in the state’s hardest-hit area per capita — an epidemic curve based on the date that symptoms began for each confirmed case.
The Idaho Statesman reached out to Central District Health in Boise and Southwest District Health in Caldwell to ask for similar curves for Ada (541 confirmed cases) and Canyon (179) counties, which rank first and third in the state in total confirmed cases. Blaine (467) is second.
CDH provided an epi curve for its region Thursday — covering Ada, Boise, Elmore and Valley counties. The other three counties have 20 confirmed cases combined.
Southwest District Health provided a Canyon curve Wednesday.
Those charts, along with the Blaine chart released Tuesday, can be viewed below.
CDH made its chart based on the week that symptoms began instead of the day.
“The reason that I opt for weekly versus daily graphics has to do with the incubation period of the virus, which is roughly five days on average,” Christine Myron, the spokeswoman for CDH, wrote in an email. “By keeping the data grouped by week (close to the average incubation time), we have a better opportunity to see trends over time.”
Recent days aren’t included in these charts. The people who began experiencing symptoms those days likely haven’t been through the testing process yet.
The charts show Central District Health’s coronavirus cases (primarily in Ada) peaking in the last two weeks of March and falling off in early April; Canyon’s cases peaking March 16-17 with a mostly flat curve since; and Blaine’s cases peaking March 13 (the day the first case in Idaho was announced) with significant improvement beginning the last week of March.
By contrast, Idaho’s peak for new cases reported was April 2 — a couple weeks after the peak in symptom onset.
This story was originally published April 16, 2020 at 3:17 PM.
