For a study, researchers sought to compare the relationship between COVID-19 infection and periodontitis severity in subjects with mild periodontitis versus subjects with moderate periodontitis. The study included 116 COVID-19 patients randomly divided into 2 groups based on a convenient sampling methodology. Group, I had a moderate form of COVID that necessitated hospitalization, while Group II had a mild form of COVID treated at home. In both groups, the stage of periodontal disease was assessed. In addition, laboratory parameters such as C-reactive protein (CRP), white blood cell (WBC), D-dimer, vitamin D, and lymphocytes were measured. Chi-square and multiple logistic regression analyses were used for statistical analysis. In both groups, more than 75% of the subjects were nonsmokers. Subjects with more than 1 comorbid condition were more prevalent in Group I (51.7%) than in Group II (24%). Severe periodontitis (stages 2–4) was found in 81% of Group I subjects and 46.2% of Group II subjects. Subjects in Group I was 6.32 times more likely to develop severe periodontal disease than those in Group II. Subjects with more than one comorbid condition were 4.43 times more likely to develop severe periodontitis than subjects with no co-morbidity. Severe periodontal disease was linked to moderate-to-severe COVID-19 infection, and lymphocytes, WBCs, and CRP levels were elevated in Group I subjects.