WASHINGTON - Only 27 percent of parents in the United States said they will vaccinate their kids ages 5 to 11 "right away" once a vaccine is authorized for this age group, according to a new poll released on Thursday.

The survey of the Kaiser Family Foundation was conducted between Oct 14 to 24 among a nationally representative random digit dial telephone sample of 1,519 adults.

A third of parents said they will "wait and see" how the vaccine is working before having their 5-11 year old vaccinated, while 30 percent of parents said they "definitely will not" get their 5-11 year old vaccinated.

Parents' main concerns have to do with potential unknown long-term effects and serious side effects of the vaccine, including two-thirds who are concerned the vaccine may affect their kids' future fertility.

Advisors to the US Food and Drug Administration (FDA) on Tuesday voted in favor of authorizing the Pfizer-BioNTech COVID-19 vaccine for children ages 5 to 11. The advisors said the benefits of the vaccine outweigh its risks for use in this age group.

Results from the Pfizer-BioNTech vaccine clinical trials show the vaccine is safe and 90.7 percent effective against symptomatic COVID-19 in children ages 5 to 11.

The FDA will consider formal authorization of the vaccine based on its advisors' recommendation. If authorized, it would be the first COVID-19 vaccine for younger children.