SHELTON — The city’s total number of positive COVID-19 cases jumped 18 over the past four days, according to Naugatuck Valley Health District data released Monday.

The increase comes as the school district’s numbers increased Monday to 21 cases since September with three reported — one each at Elizabeth Shelton School, Mohegan School and Perry Hill School. However, no schools are closed, according to interim Superintendent Beth Smith.

Increases in positive cases and hospitalizations statewide prompted Gov. Ned Lamont to implement new restrictions, which will take effect at 12:01 a.m. Friday.

The mandatory changes call for restaurants to return to 50 percent capacity, with no more than eight people per table. Restaurants must also close by 9:30 p.m. for seating, but takeout and delivery will be allowed after that time.

Event venues will be limited to 25 people indoors, 50 outdoors, religious gatherings are capped at 50 percent capacity, with 100 people max, and performing arts and movie theaters capped at 100 people.

“Please continue to be mindful of simple precautions that can help make a difference," NVHD Director Jessica Stelmaszek said.

She said people should “wear a mask/face covering when in public, continue to practice social distancing by keeping 6 feet away from others, wash your hands for at least 20 seconds, and stay home if you do not feel well.”

“If you are contacted by a local or state health official, or public school official, please answer or return the call,” Stelmaszek added. “Contact tracing is confidential and important information and instructions are shared during these calls.”

Overall, Valley communities’ positive cases jumped 83 from Friday to Monday. Naugatuck stands at 556 positive tests, followed by Ansonia with 363, Seymour at 289, Derby with 223 and Beacon Falls at 71.

Shelton remains in the “yellow” designation, meaning between five to nine positive cases per day per 100,000 residents over a 14-day period, while all the other Valley communities are orange (10 to 14 per 100,000), except Ansonia, which sits in the highest “red” category (15 or more per 100,000).

The designations are created with numbers from the state Department of Public Health. The data is the average daily rate of new cases of COVID-19 by municipality during the past two weeks. The data only uses cases among people living in community settings and does not include cases among people who reside in nursing home, assisted living or correctional facilities.

NVHD data shows that 253 of Shelton’s 724 confirmed cases are people who resided in a nursing home, assisted living facility, group home or other similar setting.

brian.gioiele@hearstmediact.com