Direct and Indirect Mortality Impacts of COVID-19 in the US, March-December 2020

Abstract

Excess mortality, defined as deviation from seasonal mortality patterns, indicates an increase in the number of deaths due to external factors, such as ongoing disease outbreaks. When disease prevalence cannot be accurately monitored due to limited testing, analyses of these patterns can provide crucial information regarding the total mortality burden of the outbreak. In this study, we analyze patterns of excess mortality due to both respiratory and non-respiratory causes from March to December 2020 in the United States. We assess the overall impact of the current pandemic across different states, age groups, and pandemic waves. We also discuss the secondary of impacts of COVID-19 and the associated interventions.

In Chapter 1: Introduction and Background, I provide an in-depth overview of the topics we explore in our study, including seroprevalence, excess mortality estimates, and infection fatality ratio. I compare the COVID-19 pandemic to previous outbreaks and examine what characteristics make SARS-CoV-2 such a deadly and effective pathogen.

The remainder of my thesis seeks to estimate excess mortality during the pandemic and disentangle the direct contribution of SARS-CoV-2 infections from the indirect consequences of public health interventions. We discover that the largest consequences of the COVID-19 pandemic are attributable to the direct impact of SARS-CoV-2 infections. The secondary impacts of the pandemic are most pronounced among younger age groups and are statistically related to the strength of interventions. In addition, several non-respiratory mortality causes show synchronous upticks with the pandemic trajectory, suggesting that a fraction of deaths ascribed to chronic conditions could be directly related to COVID-19 and missed by official tallies.