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neutralizing antibodies.26 Crucial role of T-cell immune response in SARS-CoV-1 infection has been clearly studied in animal models. On long term follow-up, only 8.69% (2/23) patients of SARS-CoV-1 patients have shown detectable levels of IgG at six years indicating reduce humoral immunity over time whereas durable memory T-cells were detected against SARS-CoV-1 at even >10 years after infection. These findings may help us to understand the potential cross-reactivity with existing SARS-CoV-2 and effectiveness of T-cell memory cells.7
Cirrhosis is associated with dysfunction of both innate and adaptive immune system and is a state of acquired immunodeficiency.18 Cirrhotic patients developing COVID-19 infection seem to have a worse outcome than those otherwise.27 Data on the duration of vaccine efficacy towards COVID-19 in patients with cirrhosis is sparse. Literature suggests that the underlying immune dysfunction in cirrhosis may lead to suboptimal response to vaccination as seen with hepatitis B and pneumococcal vaccines.28,29 However, recent studies have shown an improved outcome, reduced hospital stay and mortality in patients with cirrhosis undergoing COVID-19 vaccination.
Our study shows concordance in equal seroconversion in cirrhotic & immunocompetent HCW in developing comparable titers of anti-RBD and neutralizing antibodies after one year of initial dose of vaccination, however, differ in concept of booster dose requirement as persistent cellular immune response in form of induced stem cell memory & central memory were intact and similar in both cirrhotic and HCW which upon antigenic exposure have ability to mediate adequate immune response.
Several studies have revealed the disparity between B cell and T-cell mediated immune response in recipients of kidney transplant . It has been observed that prevalence of S-protein specific CD4+T in transplant recipient is comparable to healthy control despite a lower humoral response after two dose of vaccination.30Additionally, research has demonstrated that cytokines are produced by S-protein-reactive T-cells on ex-vivo antigenic stimulation indicating that they can mediate antiviral response activity and safeguard patients against severe COVID-19, despite the lack of antibodies. Consequently, relying solely on antibody detection to assess vaccination response may underestimate existing antiviral protection.31