WASHINGTON – President Donald Trump is expected to discuss the speedy development of forthcoming coronavirus vaccines at a White House summit Tuesday.Pfizer’s vaccine is expected to be endorsed by a panel of Food and Drug Administration advisers as soon as this week, with delivery of 100 million doses — enough for 50 million Americans — expected in coming months.Under its contract with Pfizer, the Trump administration committed to buy an initial 100 million doses, with an option to purchase as many as five times more.[TRENDING: This woman received the first COVID-19 vaccine | Judge scolds theme park trespasser | Chuck Yeager dies at 97]This summer, the White House opted not to lock in an additional 100 million doses for delivery in the.