Background There is growing evidence indicating that children are less affected from COVID-19. Some authors speculate that childhood vaccinations may provide some cross-protection against COVID-19. In this study, our aim was to compare the circulating antibody titers for multiple childhood vaccine antigens, as an indicator of the state of immune memory between patients with COVID-19 and healthy controls, with a specific aim to identify the association between disease severity and antibody titrations which may indicate a protective function related to vaccine or disease induced memory. Methods This study is a case-control study including 53 patients with COVID-19 and 40 healthy volunteers. COVID-19 severity was divided into three groups: asymptomatic, mild and severe. We measured the same set of antibody titers for vaccine antigens, and a set of biochemical and infection markers, in both the case and control groups. Results Rubella ( p = 0.003), pneumococcus ( p = 0.002), and Bordetella pertussis ( p < 0.0001) titers were found to be significantly lower in the case group than the control group. There was a significant decline in pneumococcus titers with severity of disease ( p = 0.021) and a significant association with disease severity for Bordetella pertussis titers ( p = 0.014) among COVID patients. Levels of AST, procalcitonin, ferritin and D-dimer significantly increased with the disease severity. Discussion Our study supports the hypothesis that pre-existing immune memory, as monitored using circulating antibodies, acquired from childhood vaccinations, or past infections confer some protection against COVID-19. Randomized controlled studies are needed to support a definitive conclusion.
【저자키워드】 COVID-19, pandemic, cross-protection, Antibody titers, 【초록키워드】 Vaccine, vaccination, antibody, children, severity, disease severity, Infection, COVID-19 severity, D-dimer, ferritin, procalcitonin, memory, Asymptomatic, Antibody titer, AST, Mild, antigens, immune memory, Severity of disease, childhood, disease, Protective, case-control study, association, Evidence, Hypothesis, Vaccinations, rubella, Bordetella pertussis, Support, circulating antibodies, control group, biochemical, healthy volunteers, control groups, healthy controls, circulating, Covid patients, pneumococcus, significantly lower, infection markers, significantly increased, Result, identify, affected, the disease, less, Level, patients with COVID-19, 【제목키워드】 vaccination, antibody, Infection, childhood, case control study,