COLUMBUS (WCMH) — As the delta variant of COVID-19 continues to increase infections in Ohio, all 88 counties have reached “high” transmission of the virus, the highest level according to the U.S. Centers for Disease Control and Prevention.

Ashtabula County in far northeastern Ohio had been the only county still a level below with “substantial” coronavirus transmission, but Ashtabula turned red on the CDC’s map on Thursday.

Ohio joins neighbors West Virginia, Kentucky and Indiana in seeing red in every county. As for other border states Pennsylvania and Michigan, just 10 counties across the two are still orange with “substantial” transmission. 3,029 U.S. counties are at the highest level of transmission, more than 94% of the nation’s counties.

The CDC’s color code system uses COVID-19 case rates and percent test positivity over seven-day periods. The case rate period currently reflects Thursday, Aug. 26, through Wednesday, Sept. 1, while percent positivity reflects Tuesday, Aug. 24, through Monday, Aug. 30.

Over those periods, Ashtabula County has seen 102 cases and 7.35% of tests result in positives. Franklin County, for comparison, has seen 3,100 cases over the past seven days and 8.07% of its tests be positive for the virus.