FILE — After grocery shopping, Matt Durkee wears a reusable respirator Friday, June 26, 2020, at 1206 N. 40th Ave. in Yakima, Wash. Starting Friday, June 27, every Washingtonian must wear a face covering in public, as mandated by the state. Yakima County businesses cannot admit customers without masks.

Yakima County’s “Mask up to open up” campaign appears to be bearing fruit.

Researchers with the Institute for Disease Modeling noted that coronavirus cases in the county dropped by 1% about the same time county officials and business leaders made concerted efforts to increase mask use by the public.

In a report released Friday, the researchers said the county has also reached a point where each infected person is transmitting the disease to just one other person.

“In Yakima County, we estimate that population prevalence has been declining while a large fraction of the population remains fully susceptible to COVID,” the report said. “This suggests that declines are due to recent interventions and changes in behavior.”

The Yakima Health District said the data vindicates efforts to encourage mask use, but also noted there is still work to do before the county can fully reopen and reduce the transmission rate to as close to zero as possible.

“The data is in, and the results are clear; our collective efforts are working” said Dr. Teresa Everson, the district’s health officer. “Let’s continue to work together to further slow the spread of COVID-19 in our community, and show we have the commitment to safely open up sooner rather than later.”

Everson issued a directive to wear face coverings in public June 3, following a survey Memorial Day weekend that found only 35% of people observed entering local businesses wore face coverings.

A follow-up survey after the campaign began found that 65% were wearing masks.

The effort to promote masks got an additional boost — and some teeth — when Gov. Jay Inslee ordered masks to be worn in public throughout the state and prohibited Yakima County businesses from serving customers who refuse to wear a mask.

Lilián Bravo, the health district’s director of public health partnerships, said while masks make a difference, it is not a cure-all. People still need to maintain 6 feet, or 2 meters, distance apart in public, wash hands often and not gather in large groups or with people outside their immediate households.

The news comes as the total number of coronavirus cases in Yakima County increased by almost 2% Saturday. Health district officials reported number of cases is now 7,170, an increase of 130 from Friday’s total.

Two more people died from the disease, bringing the total number of deaths to 136. As of Saturday, 52 people were hospitalized, a decrease of one, while the number of those using ventilators decreased by two to 13.

Health district officials say 3,475 people have recovered, meaning that they are neither hospitalized nor dead 28 days after first testing positive.

Reach Donald W. Meyers at dmeyers@yakimaherald.com or on Twitter: donaldwmeyers, or https://www.facebook.com/donaldwmeyersjournalist.