Clinical and Laboratory Differences between Delta and UK Variants of SARS-CoV-2: B.1.617.2 and B.1.1.7

At the end of 2019, the world met with the coronavirus disease 2019 (COVID-19), which will affect all humanity. Later in the course, the genetic variants of SARS-CoV-2 have emerged, bringing new questions and concerns. This study investigated differences between patients infected with the B.1.1.7 (UK variant) and the B.1.617.2 (Delta variant) regarding patient complaints, intensive care unit (ICU) admission and stay time, intubation, severe disease, mortality rates, and laboratory parameters. Hospitalized 205 patients infected with B.1.1.7 and 207 patients infected with B.1.617.2 were included in the study. Laboratory parameters, admission complaints, and the percent saturation of oxygen in the blood (SpO₂) were recorded on the same day as the diagnosis and clinical findings during their follow-up. Cough and fever were more common complaints in the B.1.1.7 infected group, whereas tiredness, joint pain, and gastrointestinal complaints were more frequent in patients infected with B.1.617.2. The B.1.617.2 infected group had higher severe disease, acute coronary syndrome (ACS), mortality rates, neutrophil, troponin, and ferritin levels. In conclusion, patients infected with B.1.617.2 had a higher risk of intubation, ACS, and mortality rates. Cough and fever were more common in B.1.1.7 infected group, whereas tiredness was more frequent in B.1.617.2 infected group. Vaccination with at least one dose of Pfizer-BioNTech or CoronaVac is independently associated with a decreased mortality risk caused by two variants (Odds Ratio 0.4).