An alarming number of Americans say they'd reject a COVID-19 vaccine, posing a risk to the country's ability to achieve widespread immunity.

Why it matters: Vaccine adoption is a matter of trust, and trust in most institutions is at generational lows. Anthony Fauci has said 70-75% of Americans will need to vaccinate to get the country on the road to normality.

Two new polls show trouble brewing:

• More than half of New York City firefighters (who are 77% white), said in a union poll that they won't get a COVID vaccination when it becomes available to first responders, the New York Post reports.
• Fewer than half of Black respondents (42%) in a Pew Research poll released Friday said they'd definitely or probably get a COVID vaccine if it were available today.

Trust has risen since early November, Margaret Talev reports from the Axios-Ipsos Coronavirus Index.

• In that stretch, three pharmaceutical trials have returned positive findings on the efficacy of their COVID vaccines.
• In our poll taken Nov. 20-23, for the first time in months, more than half of Americans (51%) say they're likely to take a first-generation COVID-19 vaccine as soon as it's available. College-educated and white Americans and Democrats are driving the trend.
• 70% overall (55% of Black respondents and 60% of Republicans) say they'd take the vaccine if public health officials say it's safe and effective.
• Pew finds that overall, 60% of respondents would definitely or probably take the vaccine if it were available today — up 9 points from 51% in September.

The Post reports that 55% of 2,053 firefighters polled last week by the Uniformed Firefighters Association (about 25% of 8,200 active members), answered "No" when asked: "Will you get the COVID-19 Vaccine from Pfizer when the Department makes it available?"

• Firefighters union president Andy Ansbro told The Post: "A lot of them probably feel they are not in a risk category, they are younger, stronger, they may have already had it and gotten through it, and feel it's not their problem."

Go deeper:Black Americans are more skeptical of a coronavirus vaccine.