Mortality rates plummeted in older adults along with other measures of severe COVID-19 illness following the coronavirus vaccine rollout in December 2020, a new federal study shows. 

Older adults were prioritized for and have had the highest rates of vaccination. The data suggest that a steady decline in severe COVID-19 cases, hospital admissions and emergency department visits are linked to getting the shot, according to investigators from the Centers for Disease Control and Prevention.

The rate ratio of COVID-19 illness has decreased by 40% for example, among adults aged 65 years and older (70 years and older for hospitalizations) when compared with adults aged 18 to 49 years. And the ratio has decreased by approximately 60% or more for the other measures, reported Michael J. Beach, Ph.D., and colleagues from the CDC COVID-19 Response Team.

During Sept. 6 to Dec. 14, 2020, before vaccines were administered, the rate ratios of COVID-19 outcomes among older adults to younger adults either were stable or increasing. But the rate ratio of COVID-19 deaths among seniors began to decrease in mid-December, and the other measures followed.

“The greater decline in COVID-19 morbidity and mortality in older adults, the age group with the highest vaccination rates, demonstrates the potential impact of increasing population-level vaccination coverage,” the authors concluded.

The Biden administration has set a goal of 70% vaccination population-wide by July 4. But the number of people in the United States getting the shot has fallen, from a peak of 3.4 million a day in April to less than 1 million shots per day, according to The Washington Post.  Twenty-eight states, plus Washington, D.C., are more than 60% vaccinated and likely will reach Biden’s goal, the Post reported. But the others are lagging behind.

The study was published Tuesday in the CDC’s Morbidity and Mortality Weekly Report.