Assessment of immuno-hematological parameters in Oxford-AstraZeneca vaccinated patients: A demographic comparative analysis

Objectives: Vaccination is pivotal in addressing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, yet comprehensive documentation of immunological and hematological outcomes, particularly with the Oxford-AstraZeneca vaccine (ChAdOx1) in Nigeria, is lacking. This multicenter study evaluated hematological and immunological correlates in individuals vaccinated with the ChAdOx1 vaccine. Materials and Methods: The study included 227 adult participants, who were enrolled and categorized based on SARS-CoV-2 infection status (non-infection, recent infection, and past infection) and vaccination phase (baseline, first dose, and second dose). SARS-CoV-2 infection status was confirmed using reverse transcription polymerase chain reaction and serological assays, while immune biomarkers (kidney injury molecule 1 [KIM-1], programmed cell death protein 1 [PD-1], and interleukin-6 [IL-6]) were measured using enzyme-linked immunosorbent assay and enzyme-linked fluorescent assay platforms. Complete blood counts were evaluated using a standard hematology analyzer. Results: In the Federal Capital Territory (FCT) cohort, white blood cell (WBC), neutrophil counts, and mean corpuscular hemoglobin concentration (MCHC) significantly increased in second-dose vaccines compared to baseline and first-dose categories. Similarly, lymphocyte, monocyte, eosinophil, red blood cell (RBC), mean cell hemoglobin (MCH), and IL-6 levels were persistently higher in the FCT cohort, irrespective of infection or vaccination status, while KIM-1 and PD-1 levels revealed no statistically significant difference between the FCT and Calabar cohorts. Conclusion: Vaccination with the ChAdOx1 vaccine was associated with immunomodulatory effects, particularly in the FCT cohort, including increased white blood cell (WBC) counts, neutrophils, and mean corpuscular hemoglobin concentration (MCHC), and reduced interleukin-6 (IL-6) and lymphocyte counts, which suggest a favorable immune trajectory following vaccination.