DENVER (KDVR) — Families are disappointed after Pfizer announced the usual two-shot vaccine does not appear strong enough for young children.

This news comes as the omicron variant continues to impact thousands of Americans.

The Pfizer trial was originally a two-shot trial for children under 5 years old, but now the drugmaker has announced it will add a third shot, extending this trial at least through early 2022.

Dr. Reginald Washington is the chief medical officer at the Rocky Mountain Hospital for Children and Presbyterian St. Luke’s Medical Center. He said he wouldn’t call Pfizer’s finding a mistake.

“I would call it gathering additional information,” Washington said, adding: “That’s the way science should operate.”

He said he believes this could delay the process toward emergency use in 3-6 months, depending on how quickly they can analyze the results of the third shot.

“During the trial for this age group, the very young infants, there were no significant side effects. That is not why the trial is being extended,” Washington said. “It’s being extended to make sure the dose and the number of doses is appropriate.”

Laura Richardson lives in Denver but is trying her hardest not to live in fear. She’s raising a 10-year-old who’s vaccinated and a 4-year-old who still isn’t eligible for the vaccine.

“I limit myself going places,” Richardson said about the fear of her two girls being exposed. “They haven’t been anywhere else other than school, honestly.”

Richardson learned about Friday’s announcement from Pfizer and said she understands these trials take time. But the longer it takes, the more she worries for her 4-year-old.

“I don’t think she understands what’s going on, which is fine,” she told FOX31 on a Zoom call. “I think it’s a huge burden to know there’s a plague going on.”

Friday’s announcement only intensified the impatience from so many parents looking to return to some semblance of normalcy.