(KIAH) — For parents waiting for an update on the coronavirus vaccine for their littlest ones, the Food and Drug Administration has cleared doses of the updated COVID-19 booster for children younger than 5 years old.

Children ages 6 months through 4 years already are supposed to get three extra-small doses of the original Pfizer COVID-19 vaccine — each a tenth of the amount adults receive — as their primary series.

As for younger children who’ve had two original Moderna shots, the FDA said the updated version will be substituted for the third shot.

The Centers for Disease Control and Prevention is expected to agree. But, few U.S. tots have gotten their initial vaccinations.

In Texas, the Department of Health and Human Services reported 41,702 children in this age group are fully vaccinated as of December 1, 2022. That is only 0.22% of the18,206,131 Texans in all age groups who are fully vaccinated.

Pfizer and its partner BioNTech said Monday that may help prevent severe illness and hospitalization from COVID-19 in little kids, at a time when children’s hospitals already are packed with youngsters hit by other respiratory illnesses.

The Associated Press contributed to this report.