Don Page, 83, from Hermon, walks along Central Street in Bangor on Jan. 6. Credit: Linda Coan O'Kresik / BDN

Maine continued to see a high number of COVID-19 cases from the virus’ delta variant well after the highly contagious omicron variant became the dominant strain in the U.S.

An analysis of virus test samples taken by Walgreens pharmacies across the nation showed that Maine had the highest percentage of delta variant cases as recently as Dec. 30. Walgreens is a major testing provider across the nation and has more than 70 stores across Maine’s 16 counties.

While the omicron variant now accounts for the vast majority of Maine’s new COVID-19 cases, the fact that the state was among the last to have a significant number of cases from the previously dominant delta strain is another data point showing that Maine generally lags the rest of the country in the spread of respiratory illnesses.

Around 44 percent of positive COVID-19 tests sampled were from the delta variant as of Dec. 30, by far the highest share in the United States, according to Walgreens’ COVID-19 index. The next highest shares were found in other largely rural states: Kansas (37 percent), West Virginia (29 percent) and Iowa (29 percent).

North Dakota was the only state not included in the data.

Walgreens’ estimates of current cases show a far higher rate of omicron in Maine. Some 94 percent of cases were presumed to be omicron as of Jan. 15, but that’s still the third-lowest rate in the U.S. Vermont and Iowa had slightly lower rates.

With a greater share of delta variant cases resulting in hospitalizations than omicron cases, the numbers from Walgreens’ analysis suggest that Maine hospitals seeing record numbers of patients could still be seeing some patients sick with the delta variant.

Walgreens’ data shows omicron coming to Maine around Dec. 12, only weeks after it was first discovered in southern Africa, and becoming Maine’s dominant strain 17 days later. Omicron made up over 70 percent of cases in the state by Jan. 4 and over 90 percent by Jan. 12, according to the tracker.

Maine Center for Disease Control and Prevention’s data show similar results from genomic sequencing of a sample of positive test results. The agency’s analysis shows that omicron represented about 44 percent of the state’s cases between Dec. 26 and Jan. 1. The next week, omicron’s share was 79 percent.

Omicron had become the dominant strain in the U.S. before Christmas.

Maine had largely followed the rest of New England in omicron’s spread, though it may have been a few days behind the rest epidemiologically, Maine CDC Director Nirav Shah said.

As a rule, Maine usually lags behind the rest of the nation in prevalence of any respiratory illness, said Dr. James Jarvis, senior physician executive of Northern Light Health’s COVID-19 response. There were also several major delta outbreaks around the holidays into the new year, he said.

“Omicron is the most widely spread variant that we are seeing right now, from a symptom perspective and from what we are seeing in our hospitals,” Jarvis said.

Walgreens has a presence in nearly 70 communities across Maine, with a location in the most populous communities of 15 of Maine’s 16 counties. There is not a Walgreens in Lincoln County’s most populous community, Waldoboro, though there are locations in Damariscotta and  Boothbay Harbor.

More than 95 percent of all new positive COVID-19 cases nationwide appear to be the omicron variant, Walgreens said. Some states have a presumed omicron rate around 99 percent or higher, including Washington, where it is estimated to be 100 percent of cases, as well as Mississippi, Louisiana, Georgia, Florida, Texas, Alabama and Hawaii.