A Report on the Relationship Between Vaccination Status, Viral Loads and Patient Outcomes Among Hospitalized Patients During the Covid-19 Omicron Variant’S Surge in Tehran, Iran Publisher



Esmaeili S ; Khaneshan AS ; Alavijeh PE ; Semnani K ; Seyedalinaghi S ; Sohrabi M
Source: Journal of Iranian Medical Council Published:2026

Abstract

Background: The present study explored patient outcomes and factors possibly associated with these outcomes among patients hospitalized with severe COVID-19 during the Omicron variant’s surge in a tertiary care center in Tehran, Iran. Methods: The study design was a retrospective observational study conducted on adults hospitalized with severe COVID-19 in a tertiary care center in Iran, from 22 December 2021 to 22 April 2022. Patients with major comorbidities were excluded. Demographics, Cycle threshold (Ct) value at diagnosis, and outcomes (length of stay, ICU admission, and mortality) were obtained from hospital archives. Vaccination status was retrieved from a national registry. The relationship between proposed prognostic factors and patient outcomes was analyzed. Results: Data from 212 in-patients with severe COVID-19 was analyzed. Patients were aged 54.7±18.6 years old. 11.3% of patients were admitted to the ICU, and overall mortality was 14.1%. Average length of stay was 6.27 days. 70.8% of patients were fully vaccinated, and 11.3% had received a booster dose. Vaccination was associated with significantly less hospital stay (p=0.006), ICU admissions (p=0.018), and mortality (p=0.024). Higher viral burden was associated with mortality (p=0.01), but not ICU admission or longer stay. Conclusion: The present study findings restate the protective role of vaccines against adverse outcomes of COVID-19 infection. However, an alarming rate of poor outcomes during the peak circulation of the Omicron variant was found – warranting further consideration. © 2026, Journal of Iranian Medical Council.