The clinical trial, called the KidCOVE study, will enroll approximately 6,750 children in the US and Canada between the ages of 6 months and 11 years old. The trial is broken into two parts. In part one, different dosages of the vaccine are being tested on the children. …The findings of part one will be used to determine which dose will be used in part two. For part two, the trial will expand to include children who are given a saline placebo, which does nothing.