The goal of this study is to evaluate the safety of using the \[5-cyano-N-(4-(4-\[11C\]Methylpiperazin-1-yl)-2-(Piperidin-1-yl)Phenyl)Furan-2-carboxamide\] (\[11C\]CPPC) radiotracer in positron emission tomography (PET) imaging of people with history of COVID-19 infection, with and without symptoms. The investigators are also interested to see whether use of this radiotracer reveals imaging differences between patients with history of COVID-19 infection and still exhibiting symptoms or healthy patients with history of COVID-19 infection but exhibiting no current symptoms.