Austin Public Health is urging all Austin and Travis County residents to wear masks indoors as coronavirus-related hospital admissions continue to surge.

APH updated the Austin-Travis County community's pandemic risk-based guidelines to Stage 3 last week, citing mounting cases and hospitalizations as well as multiple confirmed cases of the contagious COVID-19 delta variant.

As of July 19, however, the seven-day moving average of daily hospital admissions in the Austin area had surpassed 30, the threshold that usually triggers Stage 4 guidelines. Dr. Desmar Walkes, Austin-Travis County public health authority, said the community was on the "precipice" of Stage 4, and the next stage would come if the trend of 30-plus daily admissions continues.

"This is happening as a result of the impact of the delta variant in our community," Walkes said in a July 20 briefing to local officials. "This particular variant is much more transmissible."

While APH has four lab-confirmed cases of the delta variant, the Centers for Disease Control & Prevention believes delta to be the most prevalent strain of the virus in U.S. communities, accounting for around 87% of COVID-19 cases.

Walkes emphasized that vaccines remain the strongest form of protection against COVID-19, including the delta variant. Nearly all of the patients hospitalized with coronavirus are unvaccinated, she said. Still, studies suggest delta could have more success in breaking through vaccine protections than the original strain.

"People get protection from the delta variant from being vaccinated, but the levels of protection are decreased to somewhere in the neighborhood of 60%-80%," she said.

Because of delta's prevalence, Walkes said APH recommends using "layered protection" by wearing a mask in most indoor settings, regardless of vaccination status. This recommendation includes public settings, such as shopping and dining, but also social gatherings or workplaces when around individuals who are unvaccinated or whose vaccination status is unclear.

Although public schools in Texas are currently unable to mandate masking, per Texas Education Agency guidance, APH "strongly encouraged" all children over the age of 2 wear a mask, including on campus.

According to projections published by the University of Texas' COVID-19 Modeling Consortium on July 19, the community currently has an 87% probability of exceeding the local intensive care unit capacity of 200 beds for COVID-19 patients. If stricter masking measures are enforced, however, the consortium predicts the risk of surpassing ICU capacity would be closer to 2%.