Abstract
BACKGROUND: Despite advances in treatment, critically ill COVID-19 patients requiring intensive care unit (ICU) admission continue to comprise a substantial proportion of cases. However, the factors influencing poor prognosis in this population remain poorly understood. To address this knowledge gap, we conducted a prospective analysis of serum neutralizing activity against SARS-CoV-2 in 49 non-selected, critically ill COVID-19 patients enrolled in the multicenter SEVARVIR cohort between October 2022 and May 2024. METHODS: This a substudy of the SEVARVIR prospective multicenter observational cohort study (NCT05162508). We included 49 critically ill COVID-19 patients hospitalized in four French intensive care units between October 2022 and May 2024 from the 827 patients enrolled in the multicenter, prospective SEVARVIR study. Serum neutralizing titers of authentic SARS-CoV-2 isolates were measured using the S-Fuse assay and patients categorized as neutralizers if they had an anti-spike serum neutralization titer against the infecting variant > 15 and non-neutralizers if ≤ 15. Full-length SARS-CoV-2 genomes from all included patients were sequenced by means of next-generation sequencing. RESULTS: Median age was 73 years (59-75) and 34.7% of patients (n = 17/49) were female. Half of the patients (53.1%, n = 26/49) had immunosuppressive comorbidities. A large proportion of individuals lacked the capacity to neutralize their infecting variant (57.1%, n = 28/49). Neutralizing titers were significantly higher in 28-day survivors than in deceased patients (p = 0.0212) and neutralizers had a significantly lower 28-day mortality than non-neutralizers (5.0%, n = 1/21 vs. 32.1%, n = 9/28; p = 0.0312). Nine out of the ten patients who succumbed to the disease within 28 days of admission had undetectable serum neutralizing capacity, which was significantly more prevalent than in survivors (p = 0.03), irrespective of immunosuppression status. The sole patient who died despite having detectable neutralizing antibodies against SARS-CoV-2, was found to have anti-interferon auto-antibodies. CONCLUSION: These findings underscore the potential benefits of early therapeutic interventions aimed at enhancing neutralization, which may improve survival outcomes in both immunocompetent and immunocompromised critically ill COVID-19 patients.