Compared to less severe cases, patients with severe disease: were less vaccinated (40% vs. 28%, p = 0.021); presented with more confusion (26.9% vs. 6.8%), were more hypoxemic (Horowitz index (PaO2/FiO2) 261 vs. 280), had higher C-reactive protein (CRP) (12.3 vs. 4.0), had more coinfections (26.8% vs. 6.3%) and had more pleural effusion (14% vs. 2.6%) (last six all p < 0.001). Here, CRP is linked to Pleural effusion.