Just under 49% of adults surveyed indicated that they found mandatory vaccinations for schoolchildren acceptable, the data showed.
Seventy percent of Democratic respondents supported vaccine mandates for school children, compared to 27% of Republican respondents, the researchers said.
"The low acceptability of COVID-19 mandates suggests that broad mandates should be a last resort," study co-author Emily Largent told UPI.
Mandates should be used "only if the pandemic continues to rage and if efforts to increase vaccine access and to engage in public health messaging prove unsuccessful in achieving the level of vaccine uptake necessary for community immunity," said Largent, an assistant professor of medical ethics and health policy at the University of Pennsylvania.
Last week, the U.S. Food and Drug Administration granted an emergency use authorization for the first vaccine against the new coronavirus, manufactured by Pfizer and BioNTech, with the first doses earmarked for frontline healthcare workers and the elderly.
A second vaccine, from biotech firm Moderna, could be approved as soon as this week.
However, there have been concerns that too few Americans will agree to get vaccinated against COVID-19, because of concerns over the long-term safety of the shots.
To date, all of the vaccines in development have produced few, if any, side effects.
For this study, the University of Pennsylvania researchers surveyed 2,730 adults aged 18 years and older in the United States between Sept. 14 and 27.
Just over 61% of respondents indicated they would likely get the vaccine, with 77% of those who identified as Democrats saying they will take the shot, compared to 44% of Republicans.
Forty-one percent of adults surveyed said they believed state-enforced vaccine mandates for adults would be acceptable, while 48% described employer-enforced mandates as acceptable, the data showed.
Among Democrats surveyed, 61% said vaccine mandates for adults would be acceptable, compared to 23% of Republicans, the researchers said.
Among all respondents, 38% said vaccine mandates for children were unacceptable, while 45% indicated they were unacceptable for adults, the data showed.
"Vaccine mandates have drawn attention because of growing concerns that voluntary COVID-19 vaccination rates will be insufficient to stem transmission," the researchers, from the University of Pennsylvania, wrote in the study.
"We found that demographic characteristics and partisanship were associated with self-reported likelihood of COVID-19 vaccination," they said.