Introduction . Both COVID-19 vaccination and natural infection from SARS-CoV-2 generate protection against future risk of COVID-19; however, this protection wanes over time, in part due to new variants1 , 2 , 3 , 4 , 5 , 6. While waning protection from vaccination and natural infection against SARS-CoV-2 infection is well-documented6, recent analyses have also found some waning of protection against severe COVID-19 (defined as hospitalization or death)1 , 2 , ...