Serum GM-CSF is increased in the infected tissues of patients with conditions similar to late-stage COVID-19, including ARDS (Matute-Bello et al., 1997) and cytokine release syndrome (Ahmed, 2019), as well as the SARS-CoV-2 infection itself (Hue et al., 2020). Here, CSF2 is linked to acute respiratory distress syndrome.