Longevity of Humoral and Some Parameters of Innate Immune Responses Induced by SARS-CoV-2 Vaccination

Abstract

Background: The vaccines have been extremely successful in reducing clinically significant COVID-19 morbidity and mortality since their implementation in late 2020. Following vaccination, the innate immune system recognizes and eliminates vaccinated cells while coordinating adaptive immune responses in the form of antigen-specific reactions, resulting in long-term protection from viral infection. Objective: Further understanding of how the immune system functions in vaccinated participants by quantitative detection of some immunological signatures in the serum samples of SARS-CoV-2 vaccinated Iraqis and the correlation between level of protection and vaccine type. Subjects and Methods: The IgG antibody, Interleukin-1 beta, and Interferon Lambda 1(IFN-λ1) were measured in the serum of 125 samples taken from 75 vaccinated participants with two doses of Pfizer or Sinopharm vaccine, in addition to 50 healthy and unvaccinated controls. The measurement of the immunological signatures was performed using the enzyme-linked immunosorbent assay (ELISA) one month after the second dose of vaccination. Results: Elevated levels of IgG, IL-1β, and IFN-λ1 when compared to the control group, with P values of (0.0000) for each signature. Moreover, age was observed to have an association with an elevated level of the immunological signatures. However, sex was observed to have no association with the levels of these immunological signatures. Conclusion: Individuals who have been vaccinated against SARS-CoV-2 have a relatively long immune response post-vaccination, which is evidence of the good immunogenicity of COVID-19 vaccines for their effectiveness in provoking an immune response and the protection they provide in a sample of the Iraqi population.