The deadliest month yet of the coronavirus disease 2019 (Covid-19) outbreak in the United States drew to a close with certain signs of progress: Covid-19 cases and hospitalizations are plummeting, while vaccinations are picking up speed.

The question is whether the nation can stay ahead of the fast-spreading mutations of the virus.

The US death toll has climbed past 440,000, with over 95,000 lives lost in January alone. Deaths are running at about 3,150 per day on average, down slightly by about 200 from their peak in mid-January.

But as the calendar turned to February on Monday, the number of Americans in the hospital with Covid-19 fell below 100,000 for the first time in two months. New cases of infection are averaging about 148,000 day, falling from almost a quarter-million in mid-January. And cases are trending downward in all 50 states.

“While the recent decline in cases and hospital admissions are encouraging, they are counterbalanced by the stark reality that in January we recorded the highest number of Covid-19 deaths in any month since the pandemic began,” said Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention (CDC).

Deaths do not move in perfect lockstep up or down with the infection curve. They are a lagging indicator, because it can take a few weeks for people to get sick and die from Covid-19.

Dr. Philip Landrigan, an epidemiologist at Boston College, said vaccines are a factor in the sharp drop in cases but are not the primary cause. Instead, he said, the crisis has become increasingly “depoliticized” in recent weeks as more people come to grips with the threat and how they can help slow the spread of the virus.

“I don’t think you can underestimate the importance of this culture change. I think it’s critically important,” he said.

After a slow start, the vaccination drive that began in mid-December is picking up the pace. More than 32.2 million doses have been administered in the US, according to the CDC. That is up from 16.5 million on the day President Joe Biden took office, Jan. 20.