The United States' early rollout of COVID-19 vaccinations may have saved nearly 140,000 lives, a new study suggests.

Using data on state vaccination campaigns and COVID-19 deaths, researchers estimate that immunizations prevented 139,393 deaths nationwide between December 2020 and early May 2021.

On the state level, vaccinations prevented an average of five deaths for every 10,000 residents, according to the report.

The researchers said the findings send a powerful message at a time when COVID-19 cases are on the rise due to the highly contagious Delta variant.

"These vaccines have saved so many lives, and that's important for people to know," said lead researcher Sumedha Gupta, an associate professor at Indiana University-Purdue University Indianapolis.

The findings, the researchers said, also underline the importance of vaccinating people around the globe: Worldwide, COVID-19 is blamed for upwards of 4 million deaths and counting.

The United States accounts for over 600,000 of those deaths. But without vaccinations, Gupta said, that figure would have been significantly worse.

Over a year-and-a-half into the global pandemic, people are used to the grim statistics, said Dr. Gregory Poland, who directs the Vaccine Research Group at the Mayo Clinic, in Rochester, Minn.

"The public often hears about the lives lost," Poland said. "This study is talking about the lives saved by vaccinations, which is important for people to hear."

The findings, published online Aug. 18 in the journal Health Affairs, are based on the Bloomberg COVID-19 Vaccine Tracker, which has data on vaccine doses administered in each state, and The New York Times' COVID-19 in the U.S. database, which tracks COVID-19 deaths and other trends, state by state.

Gupta and her colleagues created mathematical models to estimate the number of COVID-19 deaths that would have occurred in the absence of vaccines between Dec. 21, 2020, and May 9, 2021.

On the state level, New York averted the greatest number of deaths, by the researchers' estimate: nearly 12 for every 10,000 adult residents. Hawaii, meanwhile, saw the smallest reduction, avoiding about one death per 10,000 adults.

Vaccinations also prevented an estimated 3 million cases of COVID-19 by early May, the researchers calculated. "The bigger impact, though, was on deaths," Gupta said.

Death, however, is not the only bad outcome of COVID-19. The study did not look at hospitalizations, but Poland said vaccinations presumably prevented many severe infections that would land people in the hospital — as well as cases of "long" COVID.

Another missing piece is disparities: At the time of the study, Gupta said, there was no data on vaccinations by race, so her team could not assess whether people of color benefited less.

It's well known that Black and Hispanic Americans were particularly hard-hit by the pandemic, and it's also become clear that they are lagging behind white Americans in getting vaccinated.

As of this week, 72% of U.S. adults have gotten at least one dose of a COVID-19 vaccine, according to the Kaiser Family Foundation. Black and Hispanic adults remain less likely to have received a dose, but the gap may be narrowing, the foundation says: In the past two weeks, an increasing share of vaccine doses have gone to people of color, based on federal data.

The current findings are from a period before the Delta variant took hold in the United States. Since July, "breakthrough" infections among fully vaccinated people have been rising.

Still, "breakthrough infections happen with every vaccine," Poland said, and they do not mean inoculations "aren't working."

He stressed that the COVID-19 vaccines have remained highly protective against hospitalization and death: The vast majority of Americans who are ending up in the hospital or dying from the infection are unvaccinated.

On Wednesday, the U.S. Centers for Disease Control and Prevention released data on the Pfizer and Moderna vaccines' effectiveness against hospitalization through July. Overall, they have been about 85% effective — and 90% effective among people who do not have conditions that substantially compromise the immune system.

If anything, Gupta said, the Delta variant makes vaccination even more imperative.