Effects of QazVac Vaccination on Immune and Clinical Characteristics in Patients With and Without Long COVID-19

Long COVID-19 is characterized by the persistence of symptoms and immune alterations beyond the acute phase of SARS-CoV-2 infection. Understanding the demographic, clinical, and immunological differences between individuals with and without long COVID-19 is crucial for developing targeted interventions. This observational study included 206 participants, comprising 90 patients with long COVID-19 and 116 without. Data on demographic, lifestyle, and clinical characteristics were collected, alongside immune cell profiles and SARS-CoV-2 antibody levels. Statistical analyses compared these parameters between the two groups. Long COVID-19 patients were predominantly female (77.8%), older (47.78% aged 41–60, 20% >60 years), and had higher BMI, hypertension (31.1%), and autoimmune diseases (11.1%) compared to nonlong COVID-19 individuals (P < 0.001). Clinical symptoms unique to long COVID-19 included memory loss (40.0%), hair loss (37.8%), fatigue (35.6%), and myalgia/arthralgia (28.9%), all absent in the control group (P < 0.001). Immunologically, patients with long COVID-19 exhibited distinct immune profiles, including elevated cytotoxic T cells (CD3+CD8+), reduced B cells, and higher CD4/CD8 ratios. Moreover, long COVID-19 patients had higher SARS-CoV-2 antibody levels, with 15.5% showing levels between 1000–2500 BAU/ml, compared to 6.9% in controls. These immunological biomarkers, including altered T cell subsets and antibody levels, highlight the complex immune dysregulation associated with long COVID-19. These findings could inform future clinical management and therapeutic strategies targeting immune modulation.