EPO and COVID-19: Along these lines of thought, people living at high-altitude have elevated levels of serum EPO and are therefore believed to be better protected from a severe course of COVID-19 (Arias-Reyes et al. 2020, 2021; Beall 2007; Jaramillo et al. 2021; Soliz et al. 2020; Viruez-Soto et al. 2021; Zubieta-Calleja et al. 2020).