While microglial cells expressed homeostatic marker TMEM119 as well as lysosomal-activity marker CD68 in both COVID-19 and control subjects (5A–D), COVID-19 subjects displayed a more widespread CD68+ immunoreactivity (5A–B), with statistically significant differences in CD68 immunoreactive area (expressed as percentage, A%) at the level of the medulla and midbrain, but not the pons, when compared to controls (Fig. 5e, Welch ANOVA W = 42.68; medulla p < 0.0001; pons p = 0.733; midbrain p < 0.0001). Here, CD68 is linked to COVID-19.