Correlation between Soluble Immunosenescence Biomarkers and Serum Neopterin Levels after COVID-19 Vaccination in a Geriatric Population

The geriatric population is increasing worldwide, including in Indonesia which has reached 11.01% in 2021 as the leading country in the geriatric population in Southeast Asia. Consequently, there is an increased risk of having severe infection, malignancy, and autoimmunity. Aging of immunity (immunosenescence) is responsible not only for those conditions but also affects the immune response to vaccination. The study's purpose was to analyze the correlation between immunosenescence and a decreased cellular immune response between 6 and 24 weeks after the second dose of CoronaVac vaccination in the geriatric population. This was an observational analytical study with a prospective cohort design. 73 geriatric subjects (≥ 60 years old) who had already received a second dose of CoronaVac were included. All the subjects had blood taken at 6 and 24 weeks after the second dose of CoronaVac. Serum sCD28, sCD80, and sCTLA-4 were used as immunosenescence markers. The decrease in cellular immunity was measured by the decreasing level of serum neopterin between 6 and 24 weeks following vaccine administration. There is a moderate correlation between sCD28, sCD80, and sCTLA-4 with serum neopterin at weeks 6 and 24. We also found a significant correlation between the decrease in neopterin at 6 and 24 weeks with sCD80 (p = 0.016, r = 0.282) but not with sCD28 (p = 0.078, r = 0.207) or sCTLA-4 (p = 0.017, r = 0.279). sCD80 and sCTLA-4 correlated with a more rapid decrease in neopterin level after CoronaVac vaccination in the geriatric population.