SARS-CoV-2 SPIKE Antibody Levels can Indicate Immuno-Resilience to Re-infection: a Real-World Study
Year: 2024
Type: article
Study design: Observational Study
Abstract: INTRODUCTION: The use of antibody titers against SARS-CoV-2, as a method of estimating subsequent infection following infection or vaccination, is unclear. Here, we investigate whether specific levels of antibodies, as markers of adaptive immunity, can serve to estimate the risk of symptomatic SARS-CoV-2 (re-) infection. METHODS: Anti-SARS-CoV-2 S assay. Study outcomes included the first symptomatic SARS-CoV-2 infection (per ICD-10 diagnostic codes, occurring ≥ 7 days post-antibody titer test), and severe SARS-CoV-2 infection, characterized by adverse outcomes including hospitalization, intensive care unit admission, intubation, mechanical ventilation, or death within 30 days of infection. All outcomes were assessed for 12 months following antibody measurement. Hazard ratios of subsequent symptomatic and severe infections were estimated using Cox regression with inverse probability weighting. RESULTS: Of 268,844 individuals with antibody data (April 2021-June 2022), those with levels ≥ 0.8 to < 1,000 U/mL had a 42% reduced risk of symptomatic infection within 12 months, compared with < 0.8 U/mL (HR = 0.58, 95% CI [0.55, 0.61]). The risk decreased by 53% (HR = 0.47, 95% CI [0.45, 0.49]) with ≥ 1000 to < 2500 U/mL and by 62% (HR = 0.38 [0.36, 0.39]) for ≥ 2500 U/mL. Risk of severe SARS-CoV-2 outcomes was also reduced. Subgroup analyses showed a consistent association between antibody levels and infection risk, by immune status and age. Clinically meaningful thresholds of antibody titers varied between Delta and Omicron infections. CONCLUSION: Higher antibody titer levels indicated reduced risk of developing symptomatic or severe COVID-19. Titers of ≥ 2500 U/mL indicated a 62-87% reduced infection risk. The quantitative determination of antibody titers allowed scaling of the correlate of risk to new variants.
Source: Infectious Diseases and Therapy
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $6,850
OpenAlex ID: W4405800632