Trucks will roll out Sunday morning as shipping companies UPS and FedEx begin delivering Pfizer’s vaccine to nearly 150 distribution centers across the states, said Army Gen. Gustave Perna of Operation Warp Speed, the Trump administration’s vaccine development program. Initially, about 3 million doses were expected to be shipped nationwide. Perna compared the vaccine distribution effort to D-Day, the U.S.-led military offensive that turned the tide in World War II. The vaccine was timed to arrive Monday so health workers could receive the shots and begin giving them, Perna said. The announcement came after revelations that the White House opted not to lock in an additional 100 million doses of Pfizer’s vaccine for delivery in the second quarter of 2021.