Northern Light Eastern Maine Medical Center in Bangor. Credit: Linda Coan O'Kresik / BDN

AUGUSTA, Maine — The number of COVID-19 cases in vaccinated people continues to rise with the omicron variant taking hold in Maine, but unvaccinated people are still making up a far larger proportion of the most serious hospitalizations due to the virus.

Maine data from the past month largely fit with studies finding the highly contagious omicron variant is better at evading protection from current vaccines than previous strains of the virus. Vaccines still reduce the risk of testing positive and significantly reduce risk of severe illness.

Slightly more than half of cases reported by the Maine Center for Disease Control and Prevention between Jan. 7 and Jan. 21 were among vaccinated people. That period coincides with omicron becoming the dominant strain of the virus in Maine, accounting for more than 90 percent of samples that underwent genomic testing. Because roughly three-quarters of Mainers are fully vaccinated, the data still reflect that unvaccinated people were twice as likely as vaccinated people to test positive for the virus.

Although risks remain higher for unvaccinated people, the data reflects decreased efficacy of the vaccine in preventing initial infection from the omicron variant compared to previous waves of the virus. Last fall, when the delta strain remained predominant, unvaccinated people in Maine were testing positive at more than four times the rate of vaccinated people.

Current state case reports also provide only a partial understanding of recent infections in Maine as the state is currently facing a backlog of 56,000 positive tests. Hospitalization data provide a more complete picture of the extent to which the highly contagious strain is causing severe illness among unvaccinated and vaccinated people.

Maine has seen record COVID-19 hospitalizations in the past month, putting strain on health care resources here even as omicron causes less severe cases on average. While more vaccinated people have ended up in the hospital in the past few weeks compared to earlier in the pandemic, hospitalization rates are still higher among unvaccinated people.

About 23 percent of Mainers have not had any vaccine doses, according to state data. But across Northern Light Health, the state’s second-largest hospital system, people who have not had a single dose accounted for 52 percent of hospitalized COVID-19 patients as of Wednesday. Unvaccinated patients also accounted for 61 percent of those in intensive care units and 75 percent of people requiring ventilators.

Total COVID-19 hospitalizations across the state dropped Thursday to 400, the lowest single-day figure since Jan. 11. Emergency room visits among possible COVID-19 patients have also declined steadily since mid-January.