The top U.S. infectious diseases specialist says the U.S. isn’t out of the “stunning” coronavirus pandemic, even as cases fall sharply and vaccinations expand, although “normality” may be at hand by year-end.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, spoke as the U.S. stands on the verge of a milestone few imagined when the first coronavirus cases were diagnosed a year ago: 500,000 deaths. That mark is likely to be reached in the next few days, depending on whose count is used.

“Half a million deaths. It’s just — it’s terrible. It is historic. We haven’t seen anything even close to this for well over a hundred years since the 1918 pandemic of influenza,” Fauci said on NBC’s “Meet the Press.”

“It’s something that is stunning when you look at the numbers, almost unbelievable, but it’s true.”

Senator Jack Reed, Democrat of Rhode Island, said in a statement on Sunday that reaching a half-million deaths was “unfathomable.”

“There will be a time to look back at what could have and should have been done better and hold elected officials accountable,” Reed said. “Today, we take a moment to mourn those we lost.”

On CNN’s “State of the Union,” Fauci said the U.S. could be “approaching a degree of normality” by end of year, although it’s still possible Americans will be wearing face masks into 2022.

“When it goes way down and the overwhelming majority of the people in the population are vaccinated, then I would feel comfortable in saying, you know, ‘We need to pull back on the masks,’” he said.

Covid-19 cases, hospitalizations and deaths have fallen sharply since peaking in early January. The pace of vaccinations is on the rise, with more than 61 million doses given so far, according to a state-by-state tally.

Close to 13% of of the U.S. population has had at least the first of two doses, although the rollout has been criticized for leaving much of the minority population behind.

The pace of vaccinations dipped over the past week as freezing weather gridlocked much of the southern U.S. and in some cases prevented the movement of supplies.

“The number was 6 million doses delayed,” Fauci said on NBC. “When you just, you know, put your foot to the accelerator and really push, we’ll get it up to where we need to be by the middle of the week.”

At the current pace it would take nine months or more to cover 75% of Americans with a two-dose vaccine. But a one-dose version, from Johnson & Johnson, could be approved in the U.S. within weeks, which may start to break the logjam.

“By July we will have in-hand enough vaccine to be able to vaccinate virtually anybody and everybody. It will be 600 million doses for 300 million people,” Fauci said on “Fox News Sunday.”

Discussing the recent decline in U.S. Covid cases, Fauci said it was “the natural peaking and coming down,” but also “very good and very impressive.”

“I don’t think we’ve vaccinated enough people yet to get the herd immunity,” he said on NBC. “What I don’t — and none of my colleagues — want to see is when you look at that slope to come down and to say, ‘Wow, we’re out of the woods now. We’re in good shape.’”

Fauci also said on CNN that the two vaccines currently being used in the U.S., from Pfizer/BioNTech and Moderna, “work very well against the U.K. variant” of the virus.