A significant amount of excess deaths in the United States throughout the first 30 months of the pandemic that were attributed to natural causes were actually unrecognized COVID-19 deaths, according to new research published in the journal PNAS.1 Investigators say responses to future emergencies should consider geographic variation in mortality data to target communities that may be impacted most.
People wearing masks during COVID-19 pandemic / Nicholas Felix - stock.adobe.com
“Geographic variation in the quality of cause of death reporting not only adversely affected pandemic response in areas where COVID-19 deaths were underreported, but it also reduced the accuracy of our national surveillance data and modeling,” Katherine Hempstead, senior policy adviser at the Robert Wood Johnson Foundation and coauthor on the study, said in a release.2 “Standardizing and improving death investigation and certification should be a public health priority.”
- New research published in PNAS reveals that a significant number of excess deaths attributed to natural causes during the first 30 months of the COVID-19 pandemic in the United States were actually unrecognized COVID-19 deaths.
- The undercounting of COVID-19 deaths persisted well beyond the initial phase of the pandemic, indicating ongoing challenges in accurately assessing the impact of the virus.
- Metropolitan counties in New England and the Middle Atlantic region reported COVID-19 deaths surpassing estimates of excess natural-cause deaths, emphasizing the need for tailored responses considering geographic variations.
A team of investigators led by the University of Pennsylvania and the Boston University School of Public Health conducted a study to compare estimates of excess natural-cause deaths and reported COVID-19 deaths. A model was used to produce monthly estimates of excess natural-cause mortality for 3127 counties in the US from March 2020 to August 2022. The data was then compared to reported COVID-19 deaths in metropolitan and nonmetropolitan divisions in the US Census.
Throughout the first 30 months of the COVID-19 pandemic, there were 1194610 excess natural-cause deaths across the country, of which 162886 were not reported as COVID-19. In total, 15.8 excess deaths were reported as non-COVID-19 natural causes for every 100 reported COVID-19 deaths. Of the 1031724 COVID-19 deaths, 909380 listed COVID-19 as the underlying cause and 122344 included COVID-19 elsewhere on the death certificate.
“Our findings show that many COVID-19 deaths went uncounted during the pandemic," Andrew Stokes, a corresponding author on the study, said in a release.2 “Surprisingly, these undercounts persisted well beyond the initial phase of the pandemic.”
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In terms of geographic representation, nonmetropolitan counties, the West, and the South had higher excess deaths than reported COVID-19 deaths. In both New England and Middle Atlantic metropolitan counties, reported COVID-19 deaths were higher than estimates of excess natural-cause deaths.
“This work is important because our ability to detect and correctly assign deaths during an epidemic goes to the heart of our understanding of the disease and how we organize our response,” Nahid Bhadelia, founding director of the Boston University Center for Emerging Infectious Diseases Policy and Research, said in a release.2
Study limitations include the inability to distinguish between excess natural-cause deaths that were unrecognized COVID-19 deaths and those that were related to health care interruptions and/or social and economic consequences of the pandemic, that natural-cause death counts were provisional in 2022, and that temporal analyses were conducted using monthly mortality data.
“Future research should work to differentiate unrecognized COVID-19 deaths from other excess natural-cause deaths using hospitalization and other localized data” the authors concluded. “Studies should also explore potential differences in unrecognized COVID-19 deaths by individual factors such as age, gender, racialized identity, ethnicity, and socioeconomic status and by health system and death investigation system characteristics. Studying these differences is critical for identifying populations with underestimated burdens of COVID-19 mortality.”
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1. Paglino E, Lundberg DJ, Wrigley-Field E, et al. Excess natural-cause mortality in US counties and its association with reported COVID-19 deaths. PNAS. 2024;121(6). doi:10.1073/pnas.2313661121