The county leader cited multiple forces in the summertime surge, but emphasized the current wave of vaccine hesitance and misinformation in the midst of a rampantly contagious Delta variant of the coronavirus.
According to Hidalgo, the positivity rate has doubled every two to three weeks in the county, making it faster than the previous wave of cases that began last December. She added the ICU rate has doubled every five weeks.
As far as vaccination rates, Hidalgo said a little over 50% of the county's population has been vaccinated against COVID, falling well behind President Biden's goal of 70% that he wanted met for the nation earlier this month.
And to drive home the point of vaccines, she stated that 90% of COVID patients admitted at Texas Medical Center hospitals are not vaccinated. It's a statistic that was backed by Dr. Peter Hotez, one of the region's leading infectious disease experts, who stood with Hidalgo during her briefing on the threat level.
WATCH: Luck 'about to run out' for those unvaccinated, Dr. Peter Hotez warns
"To put it bluntly, and in very stark terms, essentially anyone who is hospitalized for COVID right now - pediatric hospitalizations aside - this is adult hospitalizations. Anybody who is hospitalized or is in an ICU with COVID right now is there by choice, is there because they didn't make the effort to get vaccinated. And that's what we need to fix," Hotez said.
Hotez, the dean of the National School of Tropical Medicine at Baylor College of Medicine, also gave this warning to those who haven't gotten the vaccine and have gone this far in the pandemic without catching the virus.
"The big thing that worries me is, by now, anyone who's unvaccinated and has been lucky enough to escape COVID, your luck is about to run out. That's how transmissible this virus is," warned Hotez, as part of his own plea for people to get vaccinated now, especially as the school year draws closer.
Hotez added that while the county is doing slightly better than most areas in the southern U.S., it is still not close to where vaccination rates stand in the northeast. That will, he says, pave the way for the Delta variant to accelerate spread in this area.
"We've got about 44, 45 percent of the whole [Texas] population vaccinated," Hotez said. "That's not great, and particularly among [Black, indigenous and people of color] communities."
Hidalgo also pleaded with residents to wear face coverings until numbers get back under control, though the county judge expressed awareness for the limited power she has over ordering people to mask up. Earlier this week, Texas Gov. Greg Abbott insisted that he would not bring back a mask mandate.
It would be "inappropriate to require people who already have immunity to wear a mask," Abbott said.
SEE ALSO: Do vaccinated people need to mask up? Houston health experts weigh in amid COVID surge
Just two months ago, Hidalgo had lowered the threat level from "red" to "orange."
Then it dropped again to yellow, telling people to stay vigilant unless fully vaccinated. Level 3 means there is a moderate threat and the local healthcare system is well within capacity.
The color-coded alert system was first introduced amid the peak of the pandemic last year. It's designed to help provide the public with guidance on how to protect themselves.
These are the four levels of the COVID-19 threat system for Harris County:
- Level 1 - Severe (red) Stay Home
- Level 2 - Significant (orange) Minimize All Contacts
- Level 3 - Moderate (yellow) Stay Vigilant
- Level 4 - Minimal (green) Resume Normal Contacts
Some indicators that were considered red flags during the pandemic in 2020 have increased in Texas.
On Sunday, the state's positivity rate - the ratio of cases to tests - went above 10% for the first time since February, a threshold that Abbott has previously identified as dangerous.
Less than half of Texans, 43% as of Sunday, were fully vaccinated.
SEE MORE: Just a reminder: Here's who can and can't make you wear masks
Our partners at the Texas Tribune contributed to this report.
Eyewitness News is answering your questions about the COVID threat level and its meaning. For more, follow Marla Carter on Facebook, Twitter and Instagram.