COVID-19 deaths in the U.S. have tumbled to an average of around 600 per day — the lowest level in 10 months — with the number of lives lost dropping to single digits in well over half the states and hitting zero on some days.

Confirmed infections have fallen to about 38,000 per day on average, their lowest mark since mid-September. While that is still cause for concern, they have plummeted 85% from a peak of more than a quarter-million per day in early January.

The last time deaths were this low was early July, nearly a year ago. COVID-19 deaths in the U.S. topped out in mid-January at an average of more than 3,400 a day, just a month into the biggest vaccination drive in the nation’s history.

Dr. Amesh Adalja, an infectious disease specialist at Johns Hopkins University, said that vaccinations have played a crucial role even as the nation struggles to reach herd immunity.

“The primary objective is to deny this virus the ability to kill at the rate that it could, and that has been achieved,” he said. “We have in effect tamed the virus.”

About 45% of the nation’s adults are fully vaccinated, and nearly 59% have received at least one dose, according to the Centers for Disease Control and Prevention. This week, Pfizer’s vaccine won authorization for use in 12- to 15-year-olds, in a move that could make it easier to reopen the nation’s schools.

The overall U.S. death toll stands at about 583,000, and teams of experts consulted by the CDC projected in a report last week that new deaths and cases will fall sharply by the end of July.

Several states, including Alaska, Hawaii, Vermont and Wyoming, were averaging fewer than one death per day over the past week, according to data through Tuesday from Johns Hopkins. And even among the five states with the highest daily deaths — Michigan with an average of 65.4; Florida, 61.7; California, 48; Texas, 44; and New York, 39.3 — all but Florida’s number is going down.

California, the epicenter of the U.S. outbreak over the winter, logged 1,231 confirmed infections Wednesday, down from 40,000 at its peak.