Publication: Determination of total immunoglobulin g and immunoglobulin g subclass response against sars-cov-2 omicron variant in pfizer and sinovac vaccinated serum samples
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Date
2025-01
Authors
Ravi, Syamalan
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The COVID-19 pandemic, caused by the highly transmissible SARS-CoV-2 virus, continues to pose significant global health challenges. The emergence of variants such as Omicron has raised concerns regarding immune escape, waning immunity, and the long-term effectiveness of COVID-19 vaccines. While vaccination remains the most effective strategy in mitigating severe disease and transmission, differences in immune responses elicited by various vaccine platforms necessitate further investigation. This study aimed to evaluate the humoral immune response, focusing on total Immunoglobulin G (IgG) levels and IgG subclasses (IgG1 and IgG4), in individuals vaccinated with Pfizer-BioNTech (BNT162b2) and Sinovac (CoronaVac) vaccines. A total of 14 participants were recruited, with seven receiving Pfizer and seven receiving Sinovac. Serum samples were collected at six critical time points: pre-vaccination, post-first dose, two weeks after the second dose, and post-booster doses at two, 26, and 52 weeks. An indirect enzyme-linked immunosorbent assay (ELISA) was employed to quantify spike-specific IgG responses. The results demonstrated a significant increase in total IgG levels over time in both vaccine groups (p < 0.0001). Sinovac recipients exhibited higher total IgG levels (predicted mean: 1.984) compared to Pfizer recipients (predicted mean: 1.442). IgG1 levels remained comparable between both groups across all time points (p > 0.05), with Sinovac showing a transiently higher IgG1 response at two- and 26-weeks post-booster. In contrast, IgG4 levels significantly increased in Pfizer recipients at later booster time points (26 and 52 weeks, p < 0.05), whereas Sinovac elicited a less pronounced IgG4 response. These findings suggest that Sinovac induces a stronger early total IgG response, while Pfizer leads to a more pronounced IgG4 response after booster doses. The distinct patterns of IgG subclass distribution may influence long-term immunity and immune regulation following vaccination. Understanding these differential immune responses is essential for optimizing booster strategies, refining vaccine policies, and ensuring prolonged protection against emerging SARS-CoV-2 variants
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