Participants in the Medicare for All Rally in Los Angeles, California.

Sen. Bernie Sanders and the American public have strikingly different views of what "Medicare for All" would mean, a new poll by the Kaiser Family Foundation found.

Most Americans think they would still pay deductibles, co-pays and health insurance premiums under such a plan, and that job-based coverage would continue, according to the survey. Under the Medicare for All bill introduced by Sanders, the Vermont independent who is running for the Democratic presidential nomination, all of these elements of the current system would be eliminated.

A Kaiser researcher involved in the study said participants in focus groups conducted by Kaiser envisioned Medicare for All as an expansion of the current Medicare system. But that researcher, Liz Hamel, noted that the Sanders bill and other proposals call for more significant changes.

"Before we went into the focus groups I was surprised by the fact that there was so little understanding of what's actually in the Medicare for All proposals," Hamel said.

Medicare for All is one of the biggest issues in the 2020 race for the White House. Seven of the 23 Democratic presidential candidates, including Sanders, back Medicare for All proposals. Fellow 2020 candidates Sens. Cory Booker of New Jersey, Kirsten Gillibrand of New York, Kamala Harris of California, and Elizabeth Warren of Massachusetts co-sponsored Sanders' bill. Entrepreneur Andrew Yang and self-help author Marianne Williamson also support Medicare for All proposals.

The Kaiser survey, which polled 1,206 adults aged 18 and older, found that 69% of Americans believe they would continue to pay deductibles and co-pays when they use health-care services under a Medicare for All system. And 54% think individuals and employers would still pay health insurance premiums.

Additionally, 40% of respondents believe that under a Medicare for All system, most Americans would still get their primary health coverage from private insurance.Another 7% said they do not know where coverage would come from.

The survey had a margin of error of 3 percentage points.

During a focus group for the study, one participant said they thought private health insurance companies would "be running Medicare for All."

Previous Kaiser polling found that 56% of Americans favor a Medicare for All plan. A Reuters poll found that 70% of Americans support such a national health-care plan.

While Sanders' plan is most associated with Medicare for All, his presidential rivals hold different views about what a national health plan would mean. For example, some candidates have said they would preserve pieces of the private insurance market.

An NBC exit poll at the 2018 midterm elections also found that healthcare was the biggest issue for voters, ahead of any other issue.

The same new Kaiser poll also found that 87% of Democrats and Democratic-leaning independents think it is "very important" for candidates to discuss health care in the upcoming debates. It tops all other issue including climate change, gun policy, the economy, and immigration.

Republicans and Republican-leaning independents were not polled on this question, according to Hamel.