DENVER (KDVR) — K-12 schools are now the leading source of COVID-19 outbreaks in Colorado, but only a few counties outside the Denver metro area are driving those numbers – Douglas, El Paso and Mesa.

Healthcare facilities for the elderly still lead as the combined largest outbreak sources, which is defined as a facility where five confirmed or probably cases can be traced to. Together, assisted living and skilled nursing facilities have experienced 103 outbreaks since Aug. 1.

Schools are the largest single source, though.

Colorado’s Department of Public Health and Environment defines an outbreak as five or more confirmed or probable COVID-19 cases within a 14-day period (with at least one of those cases confirmed). The definition is more strict for residential healthcare and correctional facilities at just two confirmed cases over 14 days.

More than a quarter of outbreaks at K-12 schools

Since Aug. 1, 79 COVID outbreaks have happened at K-12 schools, this is more than one-quarter of the state’s total in that time. This is more than every other non-healthcare category combined.

This trend is spread only among a handful of counties, however, and most come only from a fraction.

Douglas County leads the state with 18 school outbreaks since Aug. 1, followed by El Paso County with 14 and Mesa County with 12. Together, these three counties account for more than half the state’s K-12 school outbreaks.

Within the Denver metro, Arapahoe County is second to Douglas with eight school outbreaks. The rest of the Denver metro’s counties have relatively small school outbreak numbers. Denver, Clear Creek and Gilpin counties have had none at all.

The picture for the Denver metro looks different when Douglas County’s school outbreaks are removed from the total.

Whereas school outbreaks account for more than 25% of the state’s outbreaks, with Douglas County missing they only account for one-eighth of the Denver metro county outbreaks.

This is still the largest single source of outbreaks other than elder healthcare settings, particularly when lumped together with child care centers.

Only one-third of the outbreaks happened at high schools, whose students are eligible for vaccination.