The Importance of Estimating Excess Deaths Regionally During the COVID-19 Pandemic

National or statewide estimates of excess deaths have limited value to understanding the impact of theCOVID-19 pandemic regionally. We assessed excess deaths in a 9-county geographically defined population that had low rates of COVID-19 and widescale availability of testing early in the pandemic, well-annotated clinical data, and coverage by 2 medical examiner's offices. We compared mortality rates (MRs) per 100,000 person-years in 2020 and 2021 with those in the 2019 reference period and MR ratios (MRRs). In 2020 and 2021, 177 and 219 deaths, respectively, were attributed to COVID-19(MR1/452 and 66 per 100,000 person-years, respectively). COVID-19 MRs were highest in males, older persons, those living in rural areas, and those with 7 or more chronic conditions. Compared with2019, we observed a 10% excess death rate in 2020 (MRR1/41.10 [95% CI, 1.04 to 1.15]), with excess deaths in females, older adults, and those with 7 or more chronic conditions. In contrast, we did not observe excess deaths overall in 2021 compared with 2019 (MRR1/41.04 [95% CI, 0.99 to 1.10]).However, those aged 18 to 39 years (MRR1/41.36 [95% CI, 1.03 to 1.80) and those with 0 or 1 chronic condition (MRR1/41.28 [95% CI, 1.05 to 1.56]) or 7 or more chronic conditions (MRR1/41.09 [95%CI, 1.03 to 1.15]) had increased mortality compared with 2019. This work highlights the value of leveraging regional populations that experienced a similar pandemic wave timeline, mitigation strategies, testing availability, and data quality.