Covid-19 was the third-leading cause of death in the U.S. last year, contributing to a 15.9% increase in the national mortality rate from a year earlier, the Centers for Disease Control and Prevention said in a report.

The disease caused by SARS-CoV-2 was the underlying or contributing cause of 377,883 deaths in the U.S. last year, according to the CDC’s National Vital Statistics System, which collects and reports provisional annual mortality data. Only heart disease and cancer were more deadly, and Covid also displaced suicide as one of the top 10 causes of death.

American Indians, Hispanics and Black people had the highest rates of death from Covid-19 by race and ethnicity, the study found. The death rate among White Americans was less than half that among Blacks and Hispanics, and the vast majority of the deaths from Covid-19 were in people aged 65 years and older, who accounted for almost 81% of deaths from the disease.

The U.S. vaccine rollout has been accelerating in recent weeks, and enough immunizations have been given to cover 22.7% of the population, according to Bloomberg’s vaccine tracker. While cases have started to rise again thanks to more-infectious variants and states opening up, deaths have fallen from a peak of more than 3,000 reported Covid-19 deaths per day in January to an average of around 1,000 daily.

In a second study, the CDC rejected the notion that many deaths from Covid-19 might have been over-counted or exaggerated. The health agency reviewed death certificates of people whose deaths had been primarily attributed to the infectious disease, but also listed another condition.

In 97% of certificates that attributed the death to Covid-19 along with another condition, the latter diagnosis tended to be what’s called a “chain-of-event condition” such as pneumonia or respiratory failure, or a “contributing condition” such as hypertension or diabetes. That means those other conditions were either brought about by Covid-19 or made the disease all the more deadly, the CDC said.

Only 2.5% of death certificates listed conditions that haven’t been associated with Covid-19, the study found. The CDC said the analysis supports “the accuracy of Covid-19 mortality surveillance in the United States using official death certificates.”

Still, the CDC suggested that the underlying cause of some deaths may not have been properly classified as Covid-19, given the limited availability of testing for the coronavirus.

This article was provided by Bloomberg News.