The most hardcore opponents of coronavirus vaccination — the group who say they'll never get one — tend to be older, whiter and more Republican than the unvaccinated Americans who are still persuadable, according to an analysis of our Axios/Ipsos Coronavirus Index.

Why it matters: As the Delta variant triggers more COVID-19 hospitalizations and deaths, mostly among the unvaccinated, the Biden administration and even some high-profile GOP political and media figures are trying to figure out how to nudge the country's vaccination rate higher.

How it works: We examined data from the five most recent waves of our national survey, from May through last week, comprising 5,232 U.S. adults.

• Seven in 10 respondents said they'd taken the vaccine. The group we wanted to understand was the remaining 30%.
• Just under one-fourth of the unvaccinated said they're very or somewhat likely to take the shots, but haven't yet. About the same share said they're not likely to do it but haven't ruled it out.
• The rest — a little more than half of all unvaccinated respondents — said they're not at all likely to get vaccinated.

The big picture: Roughly half of the people in the most persuadable group are Black or Hispanic, whereas the most resistant group is overwhelmingly white. The dug-in opponents also identify more solidly as Republican, and are disproportionately concentrated in the South.

Between the lines: Two additional themes unite those most resistant to being vaccinated.

• They're most likely to say they don't consume traditional mainstream news, and they're most likely to distrust authority figures or institutions, including the Centers for Disease Control and Prevention, President Biden and state governments.

What we're watching: Parents with children at home were disproportionately likely to resist taking the vaccine themselves — a potential complication to efforts to increase child vaccination rates.

• They comprised just 18% of the vaccinated respondents — but 23% of those saying they're likely to get vaccinated, 29% of those saying they're unlikely to and 31% of those saying they're not at all likely to do it.

What they're saying: "There's three different groups that will require at least three different types of outreach," said pollster Chris Jackson, senior vice president for Ipsos Public Affairs.

• "The group that still says they're willing to get the vaccine but hasn't gotten it, it appears that is more about access to the vaccine. It's not necessarily convincing them they should; it's convincing them how they can.
• "The second group, the one that's not very likely to get the vaccine but is not necessarily the hard-pass, they're skeptical they need it," Jackson said. "That's where the persuasion effort needs to be focused. They're potentially the ones where requirements might be more effective to get them vaccinated.
• "And then the last group, there's a wide variety of reasons that people give, but it appears that their opposition to getting the vaccine is substantially ideological or has to do with their self-identity," Jackson said. "It's really hard for an outsider to convince someone to change their ideological stances. So really the only way that's going to be effective to move these people if people who are seen to be part of this group drive the movement to get this vaccine."

Methodology: This data comes from five waves of the Axios/Ipsos Poll conducted between May 7 and July 19 by Ipsos' KnowledgePanel®. These findings are based on cumulative nationally representative probability sample of 5,271 general population adults age 18 or older.

• The margin of sampling error is ±1.5 percentage points at the 95% confidence level, for results based on the entire sample of adults.
• Vaccinated (n=3702), ±1.8; Likely to get the vaccine (n=350) ±5.3; not very likely to get the vaccine (n=352) ±5.3; not at all likely to get the vaccine (n=830) ±3.5