The initial shipment of Pfizer’s COVID-19 vaccine has arrived in Washington state, and North Olympic Peninsula hospitals are preparing for their first shipments.

The first shipments of one unit — 975 doses — to each county are expected this week. However, the specific day was unclear as of Monday, said Dr. Allison Unthank, Clallam County health officer.

The state is overseeing the distribution of the expected 62,400 doses that will be delivered this week, and both Olympic Medical Center and Jefferson Healthcare hospital will receive one unit; it’s just a matter of which day it will be delivered, said Unthank and Dr. Tom Locke, Jefferson County health officer.

About 3,900 doses of the Pfizer vaccine arrived at the University of Washington Medical Center in Seattle early Monday morning. The vaccine delivery was among the first in the state, a day after Gov. Jay Inslee said the vaccine received approval by a Western states review board.

The vaccine was approved to be administered by the Food and Drug Administration on Friday through an Emergency Use Authorization.

The same week that vaccinations are starting nationwide, Clallam County confirmed four new cases of COVID-19 on Monday, and Jefferson County confirmed two new cases.

Of the four cases confirmed in Jefferson County late Saturday and on Monday, three contracted the virus from family members and one contracted the virus from an out-of-county exposure, according to a Jefferson County Public Health Facebook post.

The four new cases in Clallam County on Monday are tied to outbreaks that Clallam County Public Health has been investigating, including three additional inmates at the Clallam County Corrections Facility, raising that outbreak’s total to six, Unthank said.

The outbreak investigation into the long-term care facility in Sequim is officially completed after the facility had no new cases in more than two weeks, she added.

Both counties’ case rates also dropped, with Jefferson County falling to about 94 cases per 100,000 population for the past two weeks, and Clallam County dipping to 168 cases per 100,000 for the same time period, Locke and Unthank said.

The first round of vaccine is prioritized for frontline healthcare workers, frontline first responders and long-term care facility staff and residents.

It’s expected in Clallam County that the initial delivery will have enough to provide the first dose of vaccine to frontline hospital staff such as doctors, nurses and phlebotomists, but it will not be enough for clinics or first responders, Unthank said.

Another delivery of the Pfizer vaccine is expected in two weeks, with regular weekly shipments after that, Unthank said.

While the end of the pandemic is still a “long way off,” it is an “incredibly hopeful step,” she said.

At the same time vaccinations are starting, the state and nation are seeing some of the highest COVID-19 case activity and hospitalizations since March, Locke said.

“This is supposed to be a time of great hope, but it’s also a time of great peril,” Locke told the Board of Jefferson County commissioners during his Monday morning briefing. “We’re going to be doing this at a time when the pandemic will be raging around us.”

Authorities say there are about 500,000 people in Washington eligible for the vaccine in the initial phase. Washington’s population is about 7.5 million.

“We believe that if everything goes according to plan, we’ll have most people in Washington vaccinated by mid-summer,” Michele Roberts, one of the leaders of the state Department of Health vaccine planning group, said in a statement.

By the end of December, the state expects to get another 222,000 doses of the Pfizer vaccine. And, if a vaccine developed by Moderna gets approval — which the FDA may approve at the end of this week — the state says it should get about 183,800 doses of that vaccine by the end of the month.

The test positivity on the Peninsula — the percentage of tests returned positive — also lowered in both counties to 4.9 percent in Clallam County for Nov. 27 through Dec. 11, and 1.72 percent in Jefferson County for Dec. 7 through Dec. 13.

So far this month, Jefferson County has confirmed 25 cases of COVID-19, about 12.8 percent of the 195 total cases the county has confirmed since March, according to Jefferson County Public Health data.

Clallam County has confirmed 109 cases this month, about 17.4 percent of the 625 total cases the county has confirmed since March, according to Clallam County Public Health data.

There are currently 92 active COVID-19 cases in Clallam County with one person hospitalized, and 10 active cases in Jefferson County, public health data said.