Hans Wehrili's Nude in Steel, 1967 is displayed with a COVID-19 mask on outside the Palo Alto library in Palo Alto, Calif., on July 29, 2021. (Harika Maddala/ Bay City News)

More stringent masking rules were reinstated Thursday in Alameda County to protect against the spread of COVID-19, county health officials said Friday.

State officials are again requiring masking for staff and residents in homeless shelters, emergency shelters, and cooling and heating centers, while county correctional and detention centers must now comply with both state and local guidance.

Masking continues to be required in health care and long-term care facilities.

The previous rules were reinstated because hospital use for COVID-19 patients has increased in the county based on numbers from the federal Centers for Disease Control and Prevention.

“We have observed worsening increases in COVID-19 case reports and hospitalizations since October,” said Alameda County Health Officer Dr. Nicholas Moss in a statement. “Taking actions like masking and staying home when sick can prevent spreading illnesses like COVID-19, flu, and RSV and help protect our health care system from strain.”

Daily reports of COVID-19 and hospitalizations in the county are rising quickly, health officials said. As of Thursday, 149 county residents are hospitalized with COVID-19 and the case rate averaged over seven days is 21 per 100,000 residents.

COVID-19 spreads through the air, according to the public health department, so residents should consider wearing a mask again if they have stopped. Children under 2 years old should not wear a mask, health officials said.

Residents at risk for severe illness and their households are advised to wear a mask in crowded indoor places.

Adults and some teenagers can get free medication to prevent hospitalization from COVID-19 if they have even mild symptoms and they test positive for the disease, according to health officials.

People can talk to a health provider about the options or visit https://covid19.ca.gov/treatment. Alameda County’s community support line at (510) 268-2101 can also help residents understand their treatment options.