P
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