(NEXSTAR) – Now in the third year of the COVID-19 pandemic, one U.S. demographic is still unprotected against the virus – children under the age of 5.

After the highly infectious omicron variant brought an onslaught of positive COVID tests that resulted in a high number of pediatric hospitalizations, many parents were left wondering when they might be able to vaccinate their young children.

So for parents anxious to protect their youngest children and exhausted from balancing COVID-related school closures and work, when can they expect the vaccine to become available?

Unfortunately, the answer still isn’t clear – but it appears to be a matter of months, not weeks.

Dr. Anthony Fauci told CNN that he hopes it will happen “in the next few months” but added that “we just don’t know and that’s just the reality.”

Dr. Scott Gottlieb, the former commissioner of the Food and Drug Administration and a current Pfizer board member, told CBS’ “Face the Nation” Sunday that he didn’t expect a vaccine for children under 5 before late March, at the earliest.

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Gottlieb explained that the Pfizer tests used the lowest possible dose for young kids, but that may have delayed the approval process.

“You want to make sure the vaccine is very tolerable in young kids, but probably because of that low dose, we saw less vaccine effectiveness,” Gottlieb said. “There were more infections in the children who were vaccinated than what we saw in a comparable group of 16 to 25-year-olds.”

Regulators working with Pfizer extended the trial to see if a third dose would boost protection against omicron infection, Gottlieb said. Even if the FDA decided to reconsider the vaccine to at least give children some baseline immunity against the virus, he told CBS approval and distribution likely couldn’t happen before late March.

Pfizer announced in December that it would be extending the trial to include the third dose and expects to have results in the first half of 2022.

Earlier this month, Moderna said that the data from its trials would be ready in March and the company would “proceed with regulatory filings for children 2-5 years of age thereafter.”

Once all of the data is in, the FDA will review it for emergency use authorization before it goes to a Centers for Disease Control and Prevention committee for recommendation.