Moving to further blunt the spread of the coronavirus, Gov. Jay Inslee on Tuesday said people in Washington must wear a mask or cloth face covering in any indoor or outdoor public setting.

The order will take effect Friday and, if widely followed, could be the best weapon in the state’s battle to contain the virus responsible for a pandemic that’s claimed nearly 1,300 lives in the state since February.

Until a vaccine or cure is developed, this is going to be our best defense, Inslee said at a televised news conference.

Recent scientific models show widespread mask wearing can reduce the incidence of COVID-19 cases by as much as 80%, he said. And there is also mounting evidence in other countries of a correlation between widespread mask usage and diminished spread of the virus, he said.

You won’t have to don a face covering while eating in restaurants or when alone with household members if you are able to maintain six-foot social distance.

There will be exemptions for the deaf or hard of hearing when they are actively communicating with someone else. And the order does not require children under the age of 5 to wear them. However, it is still strongly recommended for those aged 3 to 5.

Workers in Washington have been required to wear a mask or face covering since June 8 except when working by themselves in an office, or at a job site, or if they have no in-person interactions. Employers must provide cloth facial coverings to them, although employees can wear their own if it meets the minimum requirements.

Also Tuesday, Inslee ordered additional restrictions in Yakima County, where cases are surging far faster than the rest of the state. He said Saturday that the infection rate there is 28 times that of King County. Yakima County is one of only three in Washington that has remained in Phase 1 lockdown.

Inslee’s proclamation, which he first announced Saturday, requires all customers to wear a mask when entering a business, even if they are in an area that is outdoors. Also, companies must not allow any customers to enter without a face covering.

The orders also will take effect June 26.

Meanwhile, in Snohomish County, wearing a mask in public has, for weeks, been strongly recommended by the county’s public health officer, Dr. Chris Spitters.

Earlier Tuesday, he told reporters he “certainly would support” a statewide mandate, noting that wearing a facial covering “is about all of us protecting each other.”