Epidemiological and Clinical Characteristics, and Virologic Features of COVID-19 Patients in Kazakhstan: a Nation-Wide, Retrospective, Cohort Study.

Background: The earliest coronavirus disease-2019 (COVID-19) cases in Central Asia were announced in March 2020 by Kazakhstan. Despite the implementation of aggressive measures to curb infection spread, gaps remain in the understanding of the clinical and epidemiologic features of the regional pandemic. Methods: We did a retrospective, observational cohort study of patients with laboratory-confirmed COVID-19 in Kazakhstan between February and April 2020. We compared demographic, clinical, laboratory and radiological data of patients with different COVID-19 severities on admission. Univariable and multivariable logistic regression was used to assess factors associated with disease severity and death. Whole-genome SARS-CoV-2 analysis was performed in 53 patients without a recent history of international travel. Findings: Of the 1072 patients with laboratory-confirmed COVID-19 in March-April 2020, the median age was 36 years (IQR 24-50) and 484 (45%) were male. On admission, 683 (64%) participants had mild, 341 (32%) moderate, and 47 (4%) severe-to-critical COVID-19 manifestation; 20 deaths (1.87%) were reported at study exit. Multivariable regression indicated increasing odds of severe disease associated with older age (odds ratio 1.05, 95% CI 1.03-1.07, per year increase; p<0.001), the presence of comorbidities (2.13, 95% CI 1.07-4.23; p<0.031) and elevated white blood cell count (WBC, 1.14, 95% CI 1.01-1.28; p<0.032) on admission, while older age (1.09, 95% CI 1.06-1.12, per year increase; p<0.001) and male sex (5.97, 95% CI 1.95-18.32; p<0.002) were associated with increased odds of death. The Kazakhstan SARS-CoV-2 isolates grouped into seven distinct lineages O/B.4.1, S/A.2, S/B.1.1, G/B.1, GH/B.1.255, GH/B.1.3 and GR/B.1.1.10. Interpretation: Older age, comorbidities, increased WBC count, and male sex were risk factors for COVID-19 disease severity and mortality in Kazakhstan. The broad SARS-CoV-2 diversity suggests multiple importations and community-level amplification, likely predating the declaration of state emergency. Continuous epidemiologic and genomic surveillance may be critical for a better understanding of the regional COVID-19 dynamics.