U.S. has administered 556,208 vaccine shots in first week

The shots, made by Pfizer Inc. and BioNTech SE, are being distributed mostly to front-line health-care workers around the country. In total, 556,208 shots have been administered of 2.84 million distributed so far, the agency said online. The Atlanta-based CDC is tracking the shots as part of the nationwide rollout, as well as to monitor their safety.