Clinical and Laboratory Characteristics of Hospitalized Patients With COVID-19 After Vaccination in Quchan-Iran

Background: COVID-19 is the latest and most important global health crisis, which challenged even the most advanced healthcare systems in the world. Effective vaccination is the only solution to prevent infection and reduce the disease severity and mortality rate. The present study aimed to determine the clinical and laboratory characteristics of hospitalized patients with COVID-19 after vaccination in Quchan County, Iran. Materials and Methods: This is an observational analytical study with a cross-sectional scheme. The study population includes the one-year data of COVID-19 patients admitted to Musa Ibn Jafar Hospital in Quchan, Iran from March 2021 until March 2022. The data were divided into two groups vaccinated (n=123) and un-vaccinated (n=123). Three post-vaccination time windows of “no immunity”, “partial immunity”, and “full immunity” were defined to determine the length of hospitalization and death rate due to COVID-19 based on the type of vaccine. The data were collected from patient’s medical files recorded in the archive system of the hospital, the SIB system, or by calling patients or their families. Results: The mean age of vaccinated patients was higher than that of un-vaccinated patients (P 0.001). Chest pain, muscle pain, and vomiting were significantly less common in vaccinated patients (P 0.05, P 0.01, P 0.05, corresponigly), while shivering was more common (P 0.001). The serum levels of C-reactive protein (CRP) were significantly higher in vaccinated patients (P 0.01), while the white blood cell (WBC) count was lower (P 0.05). Mortality rate (P 0.01) and the length of hospitalization (P 0.001) were significantly higher in un-vaccinated patients. Sinopharm (73.98%) and AstraZeneca (17.7%) were the most administered vaccines. All death cases occurred in the full immunity time window (two weeks after receiving the second dose of vaccine). Conclusion: Vaccination can reduce the length of hospitalization and mortality rate in COVID-19 patients. Therefore, further vaccination coverage is necessary to reduce the severity of disease, length of hospitalization, and mortality rate in these patients.