Some good news in the fight against COVID-19: A smaller portion of tests done in King County are coming back positive.

However, several parts of the county have moved in the opposite direction. The two biggest spikes in positivity rate were in Seattle’s Eastside suburbs.

In the 14-day period between July 27 and Aug. 10, the county’s positive-test rate dipped to 3.7%, according to my analysis of data from Public Health — Seattle & King County. Of the nearly 58,000 tests administered in that time, about 2,100 were positive.

That’s a bit lower than the preceding two-week period, July 13-July 27, when 3.9% of tests were positive.

But it’s worth noting that the total number of tests administered declined by more than 7,000.

The data is for King County’s 48 Health Reporting Areas (HRA), which can be as small as neighborhoods or can include whole cities and towns in less populated areas of the county.

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The highest rates of positive tests have been, and remain, in South King County. But that’s also where the greatest improvements are: the four biggest percentage-point declines in positive-test rates are all in this part of the county.

The HRA known as Auburn South, which previously had the highest positive rate in the county, saw the biggest decline — down more than 3 percentage points to a little less than 10%. This area had 67 confirmed cases of COVID-19 out of 685 tests for the two-week period.

The other biggest declines were in the Kent West, East Federal Way, and SeaTac/Tukwila HRAs.

But even with the falling numbers, these areas all still have positivity rates higher than 6%.

In the eastern suburbs, three HRAs whose positivity rates had been higher than the county average now have lower-than-average rates: Bellevue Northeast, Fairwood and Bellevue Central.

It’s not all good news, though.

In the Kirkland North HRA, the positivity rate jumped from 2% to 4.7%, by far the biggest spike of any area in the county. Kirkland North had 35 new confirmed cases between July 27 and Aug. 10, compared with 16 new cases in the previous two-week period.

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The second-biggest spike was in the Bothell/Woodinville HRA, which is adjacent to Kirkland North. This area’s positive-test rate also went from below the county average to above, jumping by 1.9 points to hit 3.9%. The number of new confirmed cases for a two-week period in Bothell/Woodinville rose from 18 to 37.

Two other HRAs saw their positive-test rates jump from below the county average to above: Renton South and Beacon Hill/Georgetown/South Park.

And in South King County, a few areas with already high positivity rates worsened. The Federal Way/Central Military Road HRA went up half a point to 11%, the highest rate in the county. The neighboring Federal Way/Dash Point/Woodmont HRA climbed 1.9 points to hit 9.9%. The Burien and North Highline HRAs also had significant increases.

On a brighter note, four HRAs had positive-test rates below 1%, up from two HRAs in the previous period. They are Vashon Island, which continues to have the lowest rate, plus three Seattle neighborhoods: Ballard, Capitol Hill/Eastlake, and Fremont/Greenlake.

Overall, 29 of the county’s HRAs saw their positivity rates decline, while 17 saw an increase. Two HRAs, both with low positive-test rates, were unchanged: West Seattle and Vashon Island.

All 48 HRAs had at least one confirmed case of COVID-19 between July 27 and Aug. 10. Vashon Island had only one. Federal Way/Central Military Road had the most, with 170.

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The city of Seattle, which includes 13 HRAs, had 516 confirmed cases in this period out of nearly 27,000 tests administered. That pencils out to an overall positive-test rate of 1.9% for the city.

Even so, there is a wide range between the Seattle HRAs with the highest and lowest rates. In the most recent two-week period, the positive-test rate was seven times higher in Beacon Hill/Georgetown/South Park than it was in Ballard.

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