Title : Evaluation of adaptive immune responses to COVID-19 vaccination in patients with comorbidities
Abstract:
In Kazakhstan, the most widely utilised vaccines against the novel strain of the virus were those developed by the Russian company Gamaleya, known as Sputnik V, and by the German company BioNTech, known as Comirnaty. Elderly patients and those with comorbidities were prioritized for vaccination due to their higher risk of severe complications from the disease. Individuals aged 50 and over with comorbidities may be at greater risk of SARS-CoV-2 infection due to immunosenescence and chronic mild systemic inflammation. At present, there are no accepted surrogates for protection against symptomatic infection or severe disease caused by the virus. This is because antibody concentrations alone may not reflect antibody function or T-cell responses. The objective of this study was to evaluate the adaptive immune responses in patients with comorbidities, including diabetes, hypertension, and oncopathology, following vaccination for SARS-CoV-2.
The following section will outline the methodology and the cohort of patients who participated in the study. The present study comprised a total of 99 hospitalized patients (mean age 67.5 years) with confirmed cases of severe acute respiratory syndrome caused by the novel coronavirus (SARS-CoV-2) using polymerase chain reaction (PCR) testing. Of these, 34 patients in the vaccinated group received two doses of Sputnik V or Comirnaty, while 65 patients in the unvaccinated control group had not received any vaccinations. Serum samples were collected for the purpose of analyzing IgG antibodies against the Spike (S) protein, as well as their avidity. This analysis was conducted using an enzyme-linked immunosorbent assay (ELISA). The degree of avidity was determined by means of an "antibody avidity index" (AI), a quantitative metric of antibody binding strength. The subsequent analysis involved the utilisation of Pearson's chi-square test, with statistical significance being established at p < 0.05. The following section will present the results of the study. Following a comparison of the two groups, it was established that the percentage of unvaccinated patients was higher in the second group. The mean age of the unvaccinated group was 57.66 ± 17.05 years, while that of the vaccinated group was 72.27 ± 14.08 years (p < 0.001). There was no observed difference in gender between the two groups. Patients who had received the vaccine exhibited a more robust antibody response, characterised by higher avidity levels, in comparison to those who had not received the vaccine. Low-avidity antibodies in serum indicated a recent infection, while high-avidity antibodies suggested past or chronic infections. The present study will include both vaccinated and unvaccinated participants.
Conclusion: The present findings emphasise the significance of IgG avidity testing in the diagnosis of recent infections in vaccinated individuals. In cases of low avidity (AI ≤ 40%), enhanced medical surveillance and prophylactic revaccination are recommended, as these patients are at greater risk of severe disease upon reinfection with SARS-CoV-2. It is recommended that testing for antibody avidity be extended to all patients, irrespective of comorbid conditions, in order to guide clinical management and improve patient outcomes.
