Pfizer announced Friday that its low-dose COVID-19 vaccine for children shows an efficacy of nearly 91 percent, which could pave the way for the kids to get inoculated. The study has not been validated by U.S. regulators, who are studying how best to open up the vaccine drive for children aged 5 to 11, which could be authorized to begin in early November. That would mean the two-shot cycle could be complete by Christmas for some children. The Food and Drug Administration plans to release its own review of Pfizer’s shot for kids later Friday, with public debate on it starting next week. After an FDA authorization, the Centers for Disease Control and Prevention still need to make recommendations on who is eligible.