Here's where things stand with COVID-19 shots for youngest Americans

Parents anxious to finally vaccinate their youngest children against COVID-19, strap in: A lot is set to happen over the next week.

On Wednesday, both Moderna and Pfizer will have to convince what’s essentially a science court -- advisers to the Food and Drug Administration -- that their shots work well in babies, toddlers and preschoolers.

Kids under 5 are the only group not yet eligible for COVID-19 vaccination in the U.S. If the agency's advisers endorse one or both shots for them -- and the FDA agrees -- there’s still another hurdle. The Centers for Disease Control and Prevention must recommend whether all tots need immunization or just those at high risk from the virus.

Adding to the complexity, each company is offering different dose sizes and number of shots. And the week won’t even start with the littlest kid debate: Moderna first will ask FDA’s advisers to support its vaccine for older children.

Only a handful of countries, including China and Cuba, have offered different types of COVID-19 vaccinations to children younger than 5.

Here’s a primer to help keep all the developments straight.