Impact of clinical-epidemiological characteristics, genomic diversity, and SARS-CoV-2 viral load on hospitalized patients with COVID-19.
Name: BRENA RAMOS ATHAYDES
Publication date: 01/09/2026
Examining board:
Name |
Role |
|---|---|
| EDSON OLIVEIRA DELATORRE | Coorientador |
| FLAVIA IMBROISI VALLE ERRERA | Examinador Interno |
| GREICIANE GABURRO PANETO | Examinador Interno |
| IGHOR LEONARDO ARANTES GOMES | Examinador Externo |
| MARCELLE FIGUEIRA MARQUES DA SILVA SALES | Examinador Externo |
Pages
Summary: COVID-19 presents distinct clinical spectra in hospitalized children and adults, with severity arising from the interaction between host factors and SARS-CoV-2 characteristics. This study aimed to investigate the relationship between clinical-
epidemiological profile, viral load, and COVID-19 severity in hospitalized patients, considering genomic diversity in children and fecal viral shedding in critically ill adults. Three studies were conducted in hospitals in Espírito Santo, Brazil: (I) 54
hospitalized children, comparing the pre- and post-Omicron periods, with viral load quantified by RT-qPCR and genomic sequencing performed using nanopore technology; (II) 227 adults admitted to ICU, evaluating clinical, laboratory, and viral
load factors associated with clinical outcome; and (III) 46 critically ill adults followed longitudinally to analyze viral load dynamics in respiratory and fecal samples. In the pediatric study (median age 19.5 months; 68.5% male), 65% presented comorbidities
and more than half required oxygen therapy, with children needing respiratory support at admission being significantly younger. The pre-Omicron period showed higher viral loads, whereas the Omicron period was associated with longer ICU stays.
Comorbidities (aHR=0.47; 95%CI: 0.26–0.86; p=0.015) and male sex (aHR=0.47; 95%CI: 0.25–0.89; p=0.020) were associated with prolonged hospitalization. Sequencing identified five circulating lineages (P.1, B.1.1, BA.1*, BQ.1.1, and BE.9).
Among critically ill adults, non-survivors were older (p<0.001) and had higher rates of hypertension (p=0.014) and chronic respiratory disease (p=0.042), along with higher leukocyte counts (p=0.001), D-dimer (p=0.028), and creatinine levels (p=0.001), a greater need for tracheal intubation (p<0.001), and higher respiratory viral load (p=0.026), which was likewise elevated among intubated patients (p=0.042). These patients more frequently developed acute kidney injury, septic shock, and cardiac
arrest (p<0.001). In the multivariate Cox model, only admission creatinine remained independently associated with in-hospital mortality (HR=1.18; 95%CI: 1.00–1.39; p=0.049), with borderline significance, while age 65 years (p=0.004) and chronic
respiratory disease (p=0.029) were associated with reduced survival. In the longitudinal study, 89.1% of fecal samples collected at admission were positive for SARS-CoV-2. By clinical outcome, viral persistence remained higher in respiratory samples (67.4%) than in fecal samples (45.7%). Patients without gastrointestinal symptoms had higher fecal viral load at admission. Elevated respiratory viral load was associated with unfavorable outcomes, whereas patients with diarrhea showed a faster decline in respiratory viral load. Viral clearance was more efficient in feces. COVID-19 severity results predominantly from host factors, modulated by viral load and genomic diversity, shaping the clinical course according to hospital context. Clinical and virological markers should be integrated into risk stratification and the management of hospitalized COVID-19 patients.
