OXFORD COUNTY — State health officials Friday reported just 38 new cases of COVID-19 in Maine Friday and no new cases of COVID-19 in Oxford County, the first time that has happened since late December.

In addition to Oxford County, four other counties — Aroostook, Knox, Piscataquis and Sagadahoc — reported no new cases. There were seven cases in Androscoggin County and three in Franklin County. There was one additional death.

The last time Oxford County reported no new cases was on Dec. 27, when the seven-day rolling average of new daily cases was 24. On Friday, the average was just 3.3.

When adjusted for population, an average of 0.57 per 10,000 residents of Oxford County tested positive for the disease, a decrease of 32% from one week ago. Statewide, there was 0.46 new cases per 10,000 people, a 33% decrease in the seven-day average compared to one week ago.

The rolling average of new cases per capita are the best indicator of sustained trends and smooths out minor day-to-day-trends.

Although Androscoggin County saw a slight upward blip in new cases toward the latter half of this week, the seven-day average decreased by 18%, from 0.73 new cases per 10,000 residents on June 4 to 0.59 new cases June 11.

In sharp contrast to the rest of central and western Maine, Franklin County’s numbers appear to be getting worse. On Friday, the seven-day average of new daily COVID-19 cases was 0.76 per 10,000 residents, a 45% increase from one week ago. Only Washington County saw a bigger jump in the one-week change, with a 60% increase in the seven-day rolling average there. York and Sagadahoc counties’ numbers also went up.

The Maine Center for Disease Control and Prevention reported 11 open outbreak investigations at sites in Androscoggin (7), Franklin (1) and Oxford (3) counties as of noon Friday. All of the sites are schools.

“Outbreak investigations open, close and sometimes reopen as Maine CDC receives new test results and new information from investigations,” spokesperson Robert Long said, cautioning that the list of current outbreak sites can change at a moment’s notice.

The Maine CDC opens an outbreak investigation at a school when there are three or more individuals from different households who test positive for the disease within a two-week period. Investigations are officially closed 28 days after the last positive test or onset of symptoms, whichever occurred last.

There are other promising signs in the fight against COVID-19: Hospitalizations on Friday reached a seven-month low, with just 45 inpatients across the state. Twenty-four individuals were listed in critical care, 14 of whom are on a ventilator.

Central Maine Medical Center reported its 12th-straight day of single-digit COVID-19 patients and the second day in a row with just three patients. Two of those individuals were in critical care but there were no patients on a ventilator.

The Lewiston hospital was hit hard by the spring surge in cases. In mid-May, CMMC was saw more than 20 patients on average over a one-week period.

“It’s wonderful to get back down to this instead of having whole units full of nothing but COVID,” Dr. Claudia Geyer said Thursday.

Patients skewed younger, sicker and unvaccinated during those months.

“I would say the theme remains that unvaccinated equals at risk for getting severe or critical COVID,” the chief of hospital medicine said. “What’s wonderful is it’s become a preventable disease.”

St. Mary’s Regional Medical Center in Lewiston, Stephens Memorial Hospital in Norway and Franklin Memorial Hospital in Farmington did not have any COVID-19 patients as of Friday morning, according to data collected daily by the Maine CDC.

Staff at Bridgton and Rumford hospitals were one patient each, both of whom were in non-critical care.

Statewide, 61.7% of all residents age 12 and older had received at least one shot of a COVID-19 vaccine and 62.5% had gotten their second shot. In Androscoggin County, 55.9% and 54.8% of residents have gotten their first and final shots, respectively. In Oxford County, 52.2% of residents have gotten either their first or final shots.

With 49.7% of residents having gotten their first shot, Franklin County is behind Androscoggin and Oxford counties but is ahead of Oxford County for final inoculations, with 52.9% of eligible residents vaccinated.

The state considers the one-shot Johnson & Johnson vaccine as a final dose in its data, which may account for why the percentage of residents in Franklin County who have completed their inoculations is higher than those who have gotten their first shot of the two-dose Moderna and Pfizer vaccines.