WW presents "Distant Voices," a daily video interview for the era of social distancing. Our reporters are asking Portlanders what they're doing during quarantine.

According to Andy Barnett, COVID-19 prevention is a lot like Swiss cheese.

"Getting COVID transmitted from one person to another is like falling through a hole in the Swiss cheese" says Barnett, medical director for Oregon Health & Science University's respiratory clinic and co-founder of consulting company Back to Work Experts. "We try to stack as many pieces of cheese as possible with holes in different places."

Back to Work Experts advises businesses—from offices buildings to bars and restaurants—how to safely operate during the pandemic. Even with state-mandated reopening requirements in place, making an indoor space truly safe for employees and customers is a case-by-case process that depends on multiple factors, hence the cheese analogy.

"We know there's no one single thing that can entirely prevent COVID transmission," says Barnett. "But the more layers we implement there, the less likely it is that something's going to fall all the way through."

WW talked to Barnett about what it takes to operate safely during the pandemic and how businesses with indoor service can gain public trust.

See more Distant Voices interviews here.