April 2 (UPI) -- The United States saw 23% more deaths than expected between March 1, 2020, and the start of this year, due primarily to the effects of the COVID-19 pandemic, which suggests the official number of U.S. coronavirus deaths is an undercount, according to an analysis published Friday by JAMA found.
More than 2.8 million people died nationally between when the first confirmed cases of the coronavirus were identified and Jan. 2, the data showed.
That's roughly 522,000 more than would be expected for the 10-month period, based on figures from 2014 through 2019.
These excess deaths were higher than the number of publicly reported COVID-19 deaths across the country, researchers said.
"The number of U.S. deaths attributed to COVID-19 is staggering, but it's an under-count," study co-author Dr. Steven H. Woolf told UPI in an email.
"The additional deaths can be explained by COVID-19 deaths in which the role of the virus was undocumented and deaths from other causes produced by disruptions from the pandemic," said Woolf, a professor of family medicine and population health at Virginia Commonwealth University in Richmond.
Officially, COVID-19 caused about 378,000 deaths across the country in 2020, according to figures released earlier this week by the U.S. Centers for Disease Control and Prevention.
This made the virus the third-leading cause of death nationally, behind heart disease and cancer, and drove a 16% increase in the nation's death rate, the agency said.
However, since the start of the pandemic, experts have questioned whether official figures have accurately counted infections and deaths, particularly during the early stages, when people may have been misdiagnosed with the flu.
For this analysis, Woolf and his colleagues analyzed death figures from the CDC's National Center for Health Statistics, a database of health trends for the United States, for 2014 to 2019.
They then used these numbers to calculate "expected" deaths for the period beginning on March 1, 2020, and ending on Jan. 2, 2021, based on totals and trends from the prior years.
Given data from the same 10-month period in the years 2014 through 2019, the United States would have expected to see roughly 2.3 million deaths in 2020.
However, more than 2.8 million deaths were reported nationally, the data showed.
Black and Hispanic people accounted for about 34% of these excess deaths, which is about 10% more than their collective share of the U.S. population, based on 2010 census figures.
"Our results, along with other research, suggest that a large number of deaths could have been prevented if states were more proactive in promoting pandemic control measures and that lifting restrictions too early cost lives," Woolf said.
"Many states seem to be making the same mistake now, lifting restrictions too soon, before vaccination can reach levels to counteract community spread and stop the emergence of variants," he said.