Three doses of Pfizer’s COVID-19 vaccine offer strong protection for children younger than 5, the company announced Monday. Pfizer plans to give the data to U.S. regulators later this week in a step toward letting the littlest kids get the shots.

The news comes after months of anxious waiting by parents desperate to vaccinate their babies, toddlers and preschoolers, especially as COVID-19 cases once again are rising. The 18 million tots under 5 are the only group in the U.S. not yet eligible for COVID-19 vaccination.

The Food and Drug Administration has begun evaluating data from rival Moderna, which hopes to begin offering two kid-sized shots by summer.