We know that essential workers have a higher risk of being exposed to the coronavirus because of the work they do.

Now, we know that risk is about 55 percent higher than nonessential workers, based on research from Independence Blue Cross and the University of Pennsylvania’s Wharton School of Business, writes The Associated Press.

Researchers analyzed the impact of the lockdown last year on infection rates for 415,000 Blue Cross policyholders and the 387,000 people living with them in southeastern Pennsylvania.

Between mid-February and early June, when the stay-at-home order was lifted, about two percent of essential workers insured by Blue Cross tested positive for COVID-19, compared to one percent of nonessential workers.

That means a 55 percent higher risk of COVID-19 infection for essential workers, according to the research.

Essential worker households also had a higher risk of being infected. For roommates, it was 38 percent higher risk and for family members, 17 percent.

The findings could help officials figure out the economic and health tradeoffs of shutdowns, mitigation, and worker classifications, said study co-author Aaron Smith-McLallen, director of health informatics for IBC.

“It does give us a way to quantify how effective these policies are,” Smith-McLallen said.

Read more about this study from The Associated Press.