During the pandemic, regions of the United States saw significant differences in Covid-19 mortality rates, according to a new study published in PLOS ONE—and these differences may be attributable to varying vaccination rates and adherence to safety precautions, such as masking.

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America sees stark regional differences in Covid-19 deaths

For the study, researchers from Georgetown University's School of Nursing & Health Studies analyzed excess mortality data from CDC between Jan. 3, 2020, and Sept. 26, 2021, which they divided into five periods:

• Period 1: Jan. 3-May 30, 2020
• Period 2: May 30-Oct. 3, 2020
• Period 3: Oct. 4, 2020-Feb. 27, 2021
• Period 4: Feb. 28-June 26, 2021
• Period 5: June 27-Sept. 26, 2021

To allow the researchers to compare regional differences, U.S. states were grouped into four standard Census regions: Midwest, Northeast, South, and West.

Overall, the researchers found that there were 895,593 excess deaths associated with Covid-19 during the study period—around 26% more Covid-19 deaths than previously reported during that time.

In addition, there were clear differences in Covid-19 mortality among regions over time, particularly between the Northeast and South. Before May 30, 2020, approximately 56% of all Covid-19 deaths occurred in the Northeast. However, since October 2020, 48% of all Covid-19 deaths occurred in the South, even though the region only makes up 38% of the U.S. population.

Since May 31, 2020, the South's Covid-19 mortality rate was 26% higher than the national rate, while the Northeast's rate was 42% lower than the national rate. The disparity between the South and Northeast was most apparent during the summer of 2020, according to the researchers. Between May 31, 2020, and Oct. 3, 2020, the South had a daily excess mortality rate of 0.539 per 100,000 people, compared with a national rate of 0.369 per 100,000 and a rate of 0.111 per 100,000 in the Northeast.

The researchers also calculated the number of potentially avoidable Covid-19 deaths in each region after May 30, 2020, when people knew more about how to treat or prevent the illness. By comparing the observed mortality rates in each region to the Northeast, which had the lowest rates for most of the period, the researchers found that 316,234 Covid-19 deaths between May 31, 2020, and Sept. 26, 2021, could have been avoided.

A majority of these avoidable Covid-19 deaths (62%) occurred in the South, and 63% occurred between May 30, 2020, and February 2021. An additional 36% of avoidable Covid-19 deaths occurred between June 27 and Sept. 26, 2021.

Comments

Michael Stoto, a professor of health systems administration and population health at Georgetown and one of the study's authors, said the study is "the first to quantify avoidable deaths and confirm that both COVID-19 deaths and avoidable deaths disproportionately occurred in the South."

According to the study's authors, the regional disparities around Covid-19 deaths may be due to differences in vaccination rates, as well fewer safety precautions, such as masking, throughout the pandemic.

In the Northeast, which had the lowest Covid-19 mortality rates, 52% of the population was fully vaccinated by June 27, 2021, and 60% were fully vaccinated by Sept. 26, 2021. In comparison, the South, which had the highest Covid-19 mortality rates, only had 40% and 49% of its population fully vaccinated by those same dates.

However, the authors noted that their findings may be confounded by other geographic differences, such as education levels and age distribution. They added that there may be more substantial differences in Covid-19 mortality between rural and urban areas within states, as well as among socio-demographic groups.

"This is one of a series of planned studies to look carefully at the response to COVID-19 in the U.S. and other countries and to learn from the experience in order to strengthen preparedness for future potential outbreaks," Stoto said. "Our team has also looked at testing and surveillance, and other COVID-19 metrics to understand how communities have come together to effectively deal with the pandemic." (CIDRAP News, 4/28; Stoto et al., PLOS ONE, 4/28; George University Medical Center news release, 4/28)