evidence: Operation Warp Speed was depending on Pfizer to deliver more than two-thirds of the vaccines expected in late 2020. But the company's initial contract, worth nearly $2 billion, contained limited reporting requirements to the federal government when there was a delay. As a result, the government didn't know how many doses were really coming, and Pfizer's estimates kept dropping, according to several people familiar with the matter. [...] Avellanet wasn't involved in Operation Warp Speed, but he has decades of experience consulting for pharmaceutical manufacturers. He said anyone from the industry probably knew — and likely cautioned — Operation Warp Speed that they were making a "big, ginormous assumption of everything going right." [...] Even as Pfizer trimmed its projections, Operation Warp Speed was "trying to be incredibly collaborative, maybe to a fault," said a person familiar with Operation Warp Speed, who declined to be identified further, adding that the federal Biomedical Advanced Research and Development Authority in particular didn't want to throw pharmaceutical companies under the bus for failing to meet initial vaccine supply expectations.