SANTA CLARA COUNTY — With 79 cases confirmed in the county on Friday, the County Public Health Department announced a mandatory order banning public or private gatherings of more than 100 people to help slow the spread of the COVID-19 coronavirus.

The ban will go into effect at 12 a.m. Saturday and last for at least three weeks.

The order also calls to ban even smaller gatherings — 35 to 100 people — unless organizers meet five conditions to reduce risk of infection, such as excluding people in high-risk categories, like older people, and discouraging anyone sick from attending.

Cases have increased threefold in the last week, said County Health Officer Dr. Sara Cody in a Friday morning press conference, with 43 cases that originated through community transmission. Thirty-seven people countywide are in the hospital.

At this point, the county expects “many, many more cases in the days and weeks to come,” Cody said.

“I recognize that we are in very difficult times,” Cody said, choking up with emotion. “These decisions are hard to make. We are balancing the public health need to slow the spread of infection with the significant impact we know these actions will have on the lives of our residents.”

By law, organizers must also ensure people can stay six feet away from each other, make hand sanitation available, and allow people to cancel for events that require payment, said County Counsel James Williams. They also must follow guidance for cleaning venues before, during and after events.

Related Articles The Latest: Italy records more than 1,600 new virus cases

Coronavirus: Santa Clara County passes 20,000 cases amid statewide decline

Watch: Where are California’s coronavirus case rates dropping, and how far?

When will the COVID-19 vaccine be ready?

Alameda County has reported a huge COVID-19 death total in recent weeks. Here’s why. The ban does not extend to activities like going to the grocery store or airports, but it includes restaurants and bars, Williams said.

Cody did not share the exact number of people tested for COVID-19 so far countywide, nor how many tests may soon be made available.

Statewide, California has been hamstrung by shortages of a key chemical needed to conduct the tests. But commercial labs are expected to come online in the coming days, meaning that testing will ramp up “rapidly,” Cody said.

Following the case increase, county officials also plan to shut all schools effective beginning March 16 through April 3, with the possibility of reopening on Monday, April 5. District offices will remain open for essential personnel.

In light of the dramatic new measures — and a broad sense of fear sweeping through the community — Santa Clara County District 2 Supervisor Cindy Chavez called on community members to check on one another, especially neighbors and older people.

“I’m asking people in our community to be responsible, because we all know this is the right thing to do,” Chavez said.