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.