The January timeline represents a fast pace for vaccine development but still means there would be no fail-safe protection from the novel coronavirus until long after most Americans are likely to have returned to work or school and until after the November presidential election.

Anthony S. Fauci, the United States’ top infectious-disease specialist, said the goal is production of hundreds of millions of doses by January, an effort dubbed “Operation Warp Speed.”

“We want to go quickly, but we want to make sure it’s safe and it’s effective,” he said on NBC’s “Today” show. “I think that is doable if things fall in the right place.”