A Robust Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)-Specific T- and B-Cell Response Is Associated With Early Viral Clearance in SARS-CoV-2 Omicron-Infected Immunocompromised Individuals.

Background: The immunological determinants of delayed viral clearance and intrahost viral evolution that drive the development of new pathogenic virus strains in immunocompromised individuals are unknown. Therefore, we longitudinally studied severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific immune responses in relation to viral clearance and evolution in immunocompromised individuals.

Methods: Among Omicron-infected immunocompromised individuals, we determined SARS-CoV-2-specific T- and B-cell responses, anti-spike immunoglobulin G (IgG) and IgG3 titers, neutralization titers, and monoclonal antibody (mAb) resistance-associated mutations. The 28-day post-enrollment nasopharyngeal specimen defined early (reverse-transcription polymerase chain reaction [RT-PCR] negative ≤28 days) or late (RT-PCR positive >28 days) viral clearance.

Results: Of 30 patients included (median age, 61.9 [interquartile range, 47.4-72.3] years; 50% females), 20 (66.7%) received mAb therapy. Thirteen (43.3%) demonstrated early and 17 (56.7%) late viral clearance. Patients with early viral clearance and patients without resistance-associated mutations had significantly higher baseline interferon-γ release, and patients with early viral clearance had a higher frequency of SARS-CoV-2-specific B cells at baseline. In non-mAb-treated patients, day 7 IgG and neutralization titers were significantly higher in those with early versus late viral clearance.

Conclusions: An early robust adaptive immune response is vital for efficient viral clearance and associated with less emergence of mAb resistance-associated mutations in Omicron-infected immunocompromised patients. This emphasizes the importance of early SARS-CoV-2-specific T- and B-cell responses and thereby provides a rationale for development of novel therapeutic approaches.