antibody levels in people who received a two-dose regiment at least six months earlier. despite the finding, an fda reviewer declined to say whether the third shot was necessary. saying data shows the two doss protect. and children as young as 5 by early november. the move is in anticipation of the fda's clearing pfizer's covid vaccine for children ages 5 to 11 in the coming weeks. the biden administration has purchased 65 million pediatric doses of the pfizer vaccine, enough to vaccinate the estimated 20 million children who would be eligible for a shot. starting next month, the biden administration will allow fully vaccinated foreign travelers to enter the united states by land. for the first time since march 2020, visitors from canada or mexico, will be able to come into the u.s. for nonessential purposes, like tourism.