Publication date: Jun 24, 2026
Humoral immune responses to SARS-CoV-2 are well documented, yet the immunopathogenic mechanisms distinguishing severe from critical disease remain incompletely defined, particularly in Middle Eastern populations. We investigated antibody responses across levels of clinical severity in a Saudi Arabian cohort. In this multicentre study, we analysed 406 participants stratified into five clinical groups: controls, asymptomatic, mild, severe, and critically ill requiring intensive care unit (ICU) admission. SARS-CoV-2-specific IgG and IgM levels were quantified alongside surrogate ACE2-RBD neutralisation activity. Associations between humoral markers, demographic factors, comorbidities, and disease severity were assessed. SARS-CoV-2-specific IgG and IgM levels differed significantly across disease severity groups (p
| Concepts | Keywords |
|---|---|
| Arabian | COVID-19 severity |
| Immunopathogenic | humoral immune response |
| Severe | IgG |
| Sex | IgM |
| Viruses | immunosenescence |
| neutralising antibodies | |
| pandemic | |
| SARS-CoV-2 | |
| Saudi Arabia |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | COVID-19 |
| disease | MESH | critically ill |
| disease | MESH | chronic illness |