Interplay of inflammatory markers and anti-SARS-CoV-2 antibodies in COVID-19 mortality: A prospective cohort study

Abstract

ObjectivesDespite high global vaccination coverage, it remains unclear how vaccination and anti-SARS-CoV-2 antibodies affect immune responses and inflammation levels in patients with COVID-19. It is further unclear whether the inflammatory response differs depending on antibody levels and whether the combination of antibody and inflammation levels in COVID-19 patients affects mortality rates. MethodsWe conducted a prospective multicenter cohort study that included 1031 hospitalized COVID-19 patients from five hospitals. Anti-SARS-CoV-2-spike antibodies, interleukin-6 (IL6), and CRP were measured on hospital admission. The prespecified endpoint was all-cause in-hospital mortality. ResultsWe observed significantly lower levels of CRP (P<0.001) and IL6 (P<0.001) in patients with antibody levels above 1200 BAU/ml. After adjusting for potential confounders, patients with high levels of inflammatory markers (CRP>6 mg/dl or IL6>100 pg/ml) combined with low levels of anti-SARS-CoV-2-spike antibodies (<1200 BAU/ml) were approximately 8 times more likely to die than patients with low inflammatory responses and high antibody levels (CRP: aHR 7.973, 95% CI 2.744-23.169, P<0.001; IL6: aHR 8.973, 95% CI 3.549-22.688, P<0.001). ConclusionHospitalized COVID-19 patients presenting with high inflammatory markers and low antibody levels exhibited the highest mortality risks. Higher antibody levels are associated with lower levels of inflammation in hospitalized COVID-19 patients.