A marquee sign along Central Street in Millinocket informs people where to register for a COVID-19 vaccine. Credit: Linda Coan O'Kresik / BDN

A national survey shows 4 out of 5 unvaccinated Maine adults still plan to get the COVID-19 vaccine, one of the highest rates among states and a positive sign as the state hopes to achieve population-level immunity from the deadly virus.

The survey, conducted by the U.S. Census Bureau over two weeks in early March, suggests demand for the vaccine in Maine remains high even though state officials raised concerns this week about some appointments going unfilled after Maine’s vaccine supply increased.

Overall, just shy of 80 percent of Maine adults surveyed who had not yet received the vaccine said they definitely or probably would get it, compared to only 73.5 percent of unvaccinated adults nationally. Maine was 10th in the nation as rates varied widely by state, ranging from as high as 88 percent in Massachusetts and Vermont to as low as 46 percent in Wyoming.

The survey found the most enthusiasm in the youngest and oldest Maine adults. About 85 percent of unvaccinated Mainers under the age of 40 said they definitely or probably planned to get the vaccine. The most hesitant group was Mainers between the ages of 40-54, only 53 percent of whom said they would definitely get the vaccine while 17 percent said they would definitely not.

Maine’s vaccine rollout has largely been based on age, so many of the older people enthusiastic about the vaccine have already had the chance to get it. The state extended eligibility to people in their 50s last week. Teachers and child care workers are also eligible to be vaccinated now, while all adults over the age of 16 are set to become eligible April 19.

As of Wednesday, more than 426,000 first doses of the Moderna and Pfizer vaccines had been administered in Maine, along with nearly 266,000 second doses and Johnson & Johnson vaccines.

There is not yet scientific consensus on what share of the population needs to be vaccinated to achieve so-called herd immunity for coronavirus, though most estimates have suggested it is at least 70 percent, which would require 950,000 Mainers to be fully vaccinated. If it were 80 percent, the number would be closer to 1.1 million Mainers — or the state’s entire adult population, as a vaccine has not yet been approved for use in children younger than 16.

Among Mainers who said they were probably or definitely not going to get vaccinated, the most commonly cited reason was concern about side effects, followed by distrust of the government or vaccines. Experts agree that the side effects of the vaccine — such injection site soreness, chills, fatigue and a low-grade fever — are mild compared to symptoms of the coronavirus. Severe allergic reactions to the vaccine are extremely rare, and providers in Maine monitor patients after each dose to ensure treatment can be administered in the event of a reaction.

Nirav Shah, director of the Maine Center for Disease Control and Prevention, encouraged Mainers in their 50s to get vaccinated on Tuesday after the state received a record 68,000 doses, leaving many appointments unfilled this week. Maine’s supply is expected to increase again next week, although federal allocations to pharmacies are not yet known.

Shah noted that the unfilled appointments did not necessarily reflect hesitancy, but could be due to a mismatch between when and where vaccines were available and people’s schedules, noting Mainers in their 50s are more likely to be working during the week compared to previously eligible groups.