The demise of the federal transportation mask mandate was particularly jarring for many parents of children under 5 anxiously waiting for word on when COVID shots will become available to their kids.

State of play: There's still a wait ahead.

Pfizer CEO Albert Bourla said this week said his company aimed to get vaccines out by June if regulators agree.

• Moderna CEO Stephane Bancel likewise told Yahoo Finance late last month that his company's vaccine likely won't be available for "a couple of months...not a couple of weeks" and needs to be shown to be safe and effective for kids before Moderna applies to the FDA.

What's happening: As Axios' Caitlin Owens reported recently, the process is fraught when it comes to vaccines for infants, toddlers and little kids.

• Part of that's due to less-than-ideal clinical trial results.
• "What happened is Omicron," Bourla told former interim CMS administrator Andy Slavitt in an interview.
• Pfizer was initially planning to submit data based on two doses for the youngest kids. But amid Omicron the efficacy of two doses in kids under 5 turned out to be 30% to 40%.
• "We told the FDA, hold the data on the second. We don’t want to get licensed based on that. We will provide to you pretty soon data on a third dose which we think will provide dramatically higher results," he said.

The big picture: We've said it before, but it bears repeating: Young children aren't likely to get severely ill from COVID, but it does happen.

• There's also an unknown level of risk that little kids who do get infected could fall victim to long COVID.
• While there are a sizable number of parents who are still unsure about vaccinating their kids, there are about as many counting down the days until their child's fifth birthday in order to race them to the doctor for shots approved for 5-to-11-year-olds — especially with more maskless people on public transportation.
• The timing was especially troubling for some families still in the midst of traveling for spring break, who started their travels under the impression the mandate would remain in place.

What's next: The U.S. Justice Department says it will appeal the ruling striking down the federal mask requirement for public transportation if the CDC determines the order is still necessary.