Top health officials warned Americans that this is no time to let their guard down. “The vaccine’s critical,” Dr. Deborah Birx, the White House coronavirus response coordinator, said on NBC’s “Meet the Press.” “But it’s not going to save us from this current surge. Only we can save us from this current surge.” … With the U.S. facing what could be a catastrophic winter, top government officials warned Americans anew to wear masks, practice social distancing and follow other basic measures — precautions that President Donald Trump and other members of the administration have often disdained.