Comparison of clinical characteristics of second and third peaks of COVID-19 pandemic: effects of vaccination and preventive measures

BACKGROUND: Understanding the differences in consequent peaks of covid-19 may guide us for better predicting future disease characteristics. in this study, we aimed to compare clinical and radiological characteristics as well as outcomes of hospitalized patients with the diagnosis of covid-19 in second and third peaks of disease. METHOD(S): We retrospectively included 303 hospitalized patients with covid-19. the study population was examined in two groups: patients hospitalized between october 2020 and January 2021 during second peak and patients hospitalized between March and June 2021 during third peak. RESULT(S): there were 171 patients in group 1 and 132 patients in group 2. the patients in group 2 were younger (64+/-13.27 vs. 56.02+/-15.39, respectively;P<0.001) and female proportion was higher (64.9% and 48.5% males;P=0.005). Smoking history and presence of comorbidities were less in group 2 (41.5% vs. 25.7%, P=0.008;and 78.5% vs. 59.1%, P<0.001) and symptom duration was shorter (median 7 days vs. 6 days, P=0.039). CT severity scores, LDH, CRP, D-dimer, Ferritin, and creatinine levels were lower in group 2 (P=0.003, P=0.008, P<0.001, P<0.001, P<0.001, respectively), and mortality ratio was lower (N.=39 [28%] vs. N.=15 [11.4%], P=0.01). Duration of hospital stay and need for intensive unit care were similar across groups (median 8 days vs. 7 days, P=0.673 and N.=39 [22.8%] vs. N.=33 [25.2%], P=0.683). CONCLUSION(S): although duration of hospital stay was lower in third peak, clinical severity scores and prognostic markers were lower compared with second peak. These may reflect the increased proportion of immunized people, and the effect of preventive measures. Copyright © 2022 EDIZIONI MINERVA MEDICA.