(Portland, OR) -- The Oregon Health Authority is opening several high-volume COVID-19 vaccination sites. The spread of the Omicron variant in several states has increased demand for the vaccine and booster shots. Omicron has not been detected in Oregon, but it has been found in Washington and California. One mass vaccination site opened on Saturday at the former Multnomah Greyhound Park in Wood Village. Several other clinics are being planned throughout the state.