A new study has predicted that the quick rollout of the COVID vaccines in the United States saved an estimated 279,000 lives and prevented more than 1.2 million hospitalizations, according to Fierce Healthcare.

However, the study has warned that a recent surge in new cases due to the highly contagious Delta variant, which was first detected in India, could reverse these gains.

Study author Dr. Alison Galvani said, “Until a greater majority of Americans are vaccinated, many more people could still die from this virus.”

Dr. Galvani is the director of the Yale Center for Infectious Disease Modeling and Analysis, which conducted the study along with the Commonwealth Fund.

The study researchers looked at what would have happened without the U.S. vaccination campaign. Since July 2, the officials have administered more than 328 million vaccine doses.

There could have been at least 121,000 deaths and over 450,000 hospitalizations if the U.S. had only achieved half of that pace.

The authors wrote, “If there had been no vaccination program, daily deaths from COVID-19 potentially would have jumped to nearly 4,500 deaths per day during a second ‘2021 spring surge’—eclipsing the observed daily peak of 4,000 during the first 2021 winter surge.”

The investigators expanded COVID-19 models to include several strains, such as the Alpha, Gamma, and Delta variants.

Using the models, they compared two scenarios – “one in which no vaccination program occurred and another under which daily vaccinations were administered at only half the actual daily pace.”

“The speed of vaccination seems to have prevented another potential wave of the U.S. pandemic in April that might otherwise have been triggered by the Alpha and Gamma variants,” the researchers wrote.

Meanwhile, the Biden administration is leaving no stone unturned in stepping up its efforts to address vaccine hesitancy, as the highly contagious Delta has become the dominant strain in the nation, accounting for more than 50% of cases now.

On Tuesday, President Biden said, “We need to go to community by community, neighborhood by neighborhood, and oftentimes, door to door— literally knocking on doors—to get help to the remaining people protected from the virus.”

He said the administration would get more vaccines in the hands of family doctors, as they are the most trusted among hesitant Americans.

Biden also said that the administration is working on sending out more mobile vaccine clinics to events and festivals so more and more people get their shots.

The article was published in Fierce Healthcare.