(NEW YORK) -- Roughly two-thirds of parents of elementary school-aged children are either holding off on getting their younger children vaccinated or refuse to do so, according to a poll released Thursday by the nonprofit KFF.
Parents of teens are more willing to get their kids vaccinated, but only about half of that age group have gotten the shot so far, KFF found.
The new findings come despite increasing evidence that the COVID-19 vaccine is safe and that kids and teens are now helping to drive the pandemic.
According to a recent analysis by the Department of Health and Human Services, cases among kids under age 18 spiked 884% since last summer. It was the largest increase in cases among all age groups.
"Most of them haven't had a chance to talk to their doctor about it yet, so I'm not surprised," Liz Hamel, vice president of public opinion and survey research at KFF, said of elementary school parents who remain hesitant.
Hamel cautions that the poll was taken before news of the omicron variant, which could sway parents. But based on how the vaccine rollout has gone so far, Hamel predicts that the third of parents who flatly refuse the vaccine won't budge even as time passes. That's because the estimation of adults who don't want the vaccine -- about 12-16% -- has remained steady for about a year.
But the other third of parents of elementary-aged children who say they want to "wait and see" to vaccinate their elementary school children will probably get their kids a shot with time.
"I do think it will take a longer time for parents to come around, but I think that that is the group that eventually will get their kids vaccinated," Hamel said.
More than 5 million children ages 5 to 11 have received at least one shot of the Pfizer vaccine since it became widely available to the public on Nov. 2, following a clinical trial involving 3,100 kids that found no safety concerns.
The Centers for Disease Control and Prevention, which tracks vaccine safety, says it hasn't seen any signs yet that the vaccine has caused serious side effects in that age group, including the myocarditis seen in a small group of older teens and young adults.
Immunization experts say that if serious side effects do occur, they would happen as soon as the immune system is triggered -- no later than two months of receiving a shot.
"Data take time to look at and collect. But so far, really there have been no signals" of safety concerns, CDC Director Dr. Rochelle Walensky told ABC News Wednesday.
"We have nearly 5 million children. I would say ... if you want your children fully vaccinated by the holidays, now is the time," she later added.
Still, many parents aren't scheduling appointments just yet. While 5 million kids have gotten at least one shot, an estimated 28 million children ages 5 to 11 are eligible.
Vaccine hesitancy appears to be partisan, according to KFF. Nearly half of Republican parents of kids ages 5 to 11 plan to refuse the vaccine for their young children, compared with 7% of Democratic parents.
"Groups of parents who are less likely to say they have a vaccinated child -- including younger parents, those without college degrees, and Republicans -- are more likely to say they don't have enough information," according to the study.