She made the announcement at Carolee Booker Elementary School in Spring ISD, where Hidalgo outlined efforts the county is undertaking to provide school districts COVID-19 rapid antigen tests.
Hidalgo's action comes in the midst of rising virus cases in southeast Texas due to the highly-contagious omicron variant, which has put pressure on local hospitals.
SEE ALSO: Harris Co. mask mandate can remain in place, state court rules
Under the county's threat level scale, red "severe" advises a "stay home, work safe" order, which was birthed from the early stages of the pandemic, unless you're vaccinated.
WATCH: Harris Co. raises COVID threat level to red in midst of virus 'tsunami'
"Level 1 signifies a severe and uncontrolled level of COVID-19 in Harris County, meaning outbreaks are present and worsening and public health capacity is strained or exceeded," the county's website states. "At this level, unvaccinated residents should take action to minimize contact with others wherever possible and avoid leaving home except for the most essential needs like going to the grocery store for food and medicine."
The move also comes several days removed from a state appeals court ruling that keeps the county's mask mandate in place as Texas Gov. Abbott continues to challenge the order.
SEE MORE: ABC13 town hall to explore omicron variant's impact in Houston area
ABC13's Miya Shay is looking into the impacts the raised threat level will have on the county. Get instant updates by following Miya on Facebook, Twitter and Instagram.