As the coronavirus spread throughout the Philadelphia region last week, the Saunders sisters watched, frustrated, from their home in Ridley Park. And while scrolling through Instagram, they suddenly found purpose.

It was a call to service, posted by Mayor Jim Kenney, for volunteers to join local efforts to respond to the pandemic.

“There’s clearly a need, and I didn’t know exactly how to be useful during it, but I figured joining a group like this would be a good way,” Julia Saunders said after finishing her training for the Delaware County Citizen Corps last week. “People seem to have a sense of panic, but if you’re doing something proactive for the people around you, it helps.”

Julia and her sister, Amy, are two of the newest additions to the suburban county’s citizen corps, which has established an emergency response center at the vacant Glen Mills School, shuttered by the state amid an investigation into abusive behavior. The school’s nearly 800-acre campus is serving as a hub where volunteers are distributing supplies, coordinating communication throughout the county, and providing a safe place for first responders to stay if they’ve been exposed to the virus.

But the group is far from a new concept — nearly 10 years old, the citizen corps had more than 500 active members, and 80 more have committed in the last two weeks, officials said. The surge is part of a regionwide interest from citizens who feel restless in this time of quarantine and social distancing. That demand is eagerly met, according to Ed Kline, who runs the corps for Delaware County’s Department of Emergency Services.

“We’re about teaching people how to take care of themselves better,” Kline said. “We’re not making police officers, firefighters, and EMTs here. We’re making a better citizen that can help people be safer.”

Delaware County isn’t alone in that objective. Surrounding counties offer similar volunteer opportunities, either through government agencies or groups like the Red Cross. In Philadelphia, the Medical Reserve Corps has 2,500 citizens on retainer, ready to handle tasks as varied as setting up disaster-relief shelters or helping direct traffic.

Members don’t need formal training, though Delaware County’s corps includes surgeons, specialists, and nurses, according to Kline. The expertise of other members is just as crucial: Marketing professionals help spread the word; forensic accountants log every volunteer’s hours and track other data.

“With the impact we have now, this is still something we need to do for the next disaster down the road,” he said. “We’ve been doing this every day for 10 years, and the things you see people doing here are the things they’ve been actively doing for smaller situations.”

Normally, Delaware County’s corps are dispatched after fires and floods, events that displace people from their homes. They also run training exercises regularly, including one in late February where they raised a shelter in a Lancaster field during a mock-outbreak of Ebola. That training became a little too prescient, according to Dennis Daye, a member of the corps since 2012.

Still, he welcomed the practice.

“Those trainings have taught us to take care of ourselves personally and our families, so we are not part of the problem, we are not victims,” said Daye, a Chester Township supervisor. “So when that’s taken care of, I can give back to the people who aren’t prepared, who aren’t ready.”

In a way, the citizen corps has become its own community, with more veteran members like Daye serving as mentors for newer recruits, like the Saunders sisters.

“Doing this gives a sense of hope,” Amy Saunders said. “I feel like everyone has been living individual lives, and this is somewhat like an umbrella: Now we’re all in this together, and we each can play a role.”