According to a new Yahoo Finance-Harris Poll, nearly two-thirds of Americans have concerns about the fast-tracked COVID-19 vaccine, the product of “Operation Warp Speed.”

In response to the survey prompt, “I feel more concerned about receiving a COVID-19 vaccine than I do about other vaccines (e.g., flu, measles, chickenpox),” 63% of respondents agreed, with 35% agreeing with the statement “somewhat” and 28% agreeing “strongly.” (Because of the comparison to other vaccines, this is a distinct issue from the anti-vaccine movement — which medical professionals and evidence strongly rejects — and is a product of the unique circumstances.)

The U.S. government – along with other public health groups – has spent millions trying to fast-track a vaccine that can end a pandemic that has infected 40.9 million people worldwide, killing 1.13 million.

This ambivalence may also manifest in policies that emerge when the vaccine arrives. Respondents were split as to whether employers should mandate workers get vaccinated before returning to the office (59% said they should) and whether schools should require all students to get vaccinated (61% said they should).

The uncertainty about a vaccine is echoed elsewhere. According to a survey by STAT, 58% of Americans in October said they would get vaccinated as soon as a vaccine was available, down from 69% who said the same thing in August.

Local officials have also expressed skepticism in the vaccine development process. Last month New York Gov. Andrew Cuomo said state health officials will review any federally approved vaccines. At a news conference, he said, "The first question is, is the vaccine safe? Frankly, I'm not going to trust the federal government's opinion.” And just this week Cuomo told “Good Morning America” that Americans should be skeptical: "My opinion doesn't matter, but I don't believe the American people are that confident. You are going to say to the American people now, 'Here's a vaccine, it was new, it was done quickly, but trust this federal administration, their health administration that it's safe, and we're not 100% sure of the consequences’,” he said.

[Read more: Americans are split on whether a vaccine will truly end the COVID-19 crisis: Poll]

Similarly California Gov. Gavin Newsom said this week that state public health officials will review any vaccines approved by the federal government before it’s distributed.

Confidence in FDA

Despite concerns about the vaccines, there is still confidence in the FDA, indicating that the issue may be less about corners being cut than simply uncharted territory. The survey found that 68% of respondents trust the FDA to make sure a vaccine is safe. This, of course, is different from trusting a vaccine will be effective, and the FDA will approve a vaccine that works just 50% of the time as long as it's safe.