Immunizations using the freshly authorized coronavirus vaccine from Moderna Inc. are slated to initiate on Monday, fueling the mass vaccination campaign that was initiated just last week.Drug distributor McKesson Corp. initiated taking doses of the vaccine from manufacturing plants on Saturday for distribution around the country. United Parcel Service Inc. and FedEx Corp. trucks began rolling out Sunday to deliver the doses to hospitals and other sites.The federal government seeks to distribute over the coming week a total of 7.9 million doses of vaccines from Moderna and Pfizer Inc., which developed the first coronavirus shot authorized for use in the US.