EVERETT — Four months after the first vaccine shipments arrived in Washington, everyone 16 and older can now get in line for a dose.

In Snohomish County, the first day of universal adult eligibility on Thursday brought 4,700 people to mass vaccination sites in Arlington, Monroe and Everett. It also marked a watershed moment of the coronavirus pandemic — giving those who received a dose a clearer vision of the path back to life as we knew it.

“Today likely comes as a relief for many now eligible for vaccines, and it’s heartening to see such a large portion of Snohomish County looking forward to being fully vaccinated,” Dr. Chris Spitters, the county’s chief public doctor, said in a statement. “Please remember that it may take time to find an appointment, but don’t give up as each week will get easier.”

So far, more than 175,000 residents in the county are fully vaccinated, according to Snohomish Health District data. Another 110,000 are waiting for a second dose.

Statewide, nearly half of all Washingtonians 16 and older have received at least one shot, Gov. Jay Inslee said during a news conference.

And the state is averaging about 57,000 doses each day.

But that number might take a slight hit because the state, among dozens of others, has paused use of the single-shot Johnson & Johnson vaccine.

State officials expect the pause to last for about a week. That gives public health experts time to educate doctors on how best to treat rare blood clots that have been found in six out of the nearly 7 million Americans who have received the single-shot vaccine.

In Washington, leaders worry the pause will make some residents hesitant to get vaccinated.

“This is a life-saving product that reduces hospitalizations and deaths at a high rate,” Inslee said. “An average American is more likely to get struck by lightning, literally, than to have an issue from this vaccine, from what we know today.”

While the number of people vaccinated rises, the state is also seeing dangerous trends in key COVID metrics, Inslee said.

“Unfortunately, there is strong evidence of a fourth wave potentially developing in the state of Washington,” he said. “We cannot, and we will not, wait for that wave to engulf us.”

Earlier this week, the state moved three counties back to Phase 2 of the state’s reopening plan. Snohomish County was not one of them.

Locally, COVID-19 cases are on the rise, but there were only 31 hospitalizations in the county on Thursday.

Spitters encouraged residents to keep wearing masks, to continue social distancing when around people they don’t live with — vaccinated or not — and to avoid gatherings.

In Olympia, Inslee asked Washingtonians to help stop the spread of the virus by taking advantage of the good weather.

“It’s a great day to take it outside,” Inslee said.

Joey Thompson: 425-339-3449; jthompson@heraldnet.com. Twitter: @byjoeythompson.