https://ift.tt/2wwdHAe In France, people with immune problems are given booster shots. Why not in the U.S.? Cancer patients and transplant recipients, among others, do not always respond well to initial vaccine doses. But there are few guidelines on whether and when to give them additional doses. BY APOORVA MANDAVILLI https://ift.tt/3hwtfZe July 5, 2021 at 12:57AM