This thesis attempts to add more evidence to the debate on universal health care coverage in the United States and if the Affordable Care Act (ACA) is effective in increasing access to healthcare and consequently improving healthcare outcomes. It specifically looks at if the expansion of Medicaid, a key component of the ACA, has led to improved COVID-19 outcomes, and more generally, lower overall mortality during the pandemic. COVID-19 led to unprecedented job losses, which in the United States also can mean loss of healthcare insurance due to the majority of workers being covered by employee-sponsored insurance. Therefore, the pandemic provides an interesting time to study if states that expanded Medicaid fared better than states that have not yet expanded Medicaid. The thesis uses multiple linear regressions to examine the impact of the expansion of Medicaid on mortality, one modeling after a difference-in-difference regression. Although research has shown that there was a larger increase in the uptake of Medicaid in states that did expand, the results do not provide evidence of a clear correlation between Medicaid expansion and lower COVID-19 deaths. I do find evidence that the states that expanded Medicaid have experienced lower overall mortality during the pandemic, but this is likely due to other differences between the expansion and non-expansion states, not necessarily due to healthcare coverage.