Background: COVID-19 is a respiratory viral disease caused by the severe acute respiratory syndrome-Coronavirus type 2 (SARS-CoV-2). The World Health Organization (WHO) declared the SARS-CoV-2 infection as well as global health emergency. COVID-19 vaccines provide strong protection against serious illness, hospitalization, and death. Objectives: This study aimed to assess the correlation between the vaccine [type, doses] and the viral load, oxygen saturation, inflammatory markers, disease severity, and morbidity among Egyptian inpatients at Assiut chest hospital as well as assess the immune status relative to different types of cytokines, and level of anti-viral spike IgG.
Methodology: The study involved eighty-nine subjects, including seventy-seven COVID-19 inpatients and twelve healthy controls. IL-18 and MCP-1, were evaluated using the Luminex® 100/200TM System, IgG antibodies against the SARS-CoV-2 spike protein's receptor binding domain (RBD) in human serum were detected using the ELISA technique. Results: increase in IgG concentration levels, oxygen saturation, clinical features (fever), and hospitalization time in vaccinated patients versus unvaccinated patients. The viral load and the levels of D-dimer, MCP-1, and IL-18 are related to vaccination status. Conclusion: According to the study, people who were not vaccinated got severe and life-threatening COVID-19 infections. The immunized population had a lower percentage of severe COVID-19 infections and overall mortality than the unvaccinated group. Two doses of vaccination were linked to a decreased mortality rate in hospitalized patients with moderate-to-severe COVID-19 infection.