Publication date: Jun 20, 2026
Acute respiratory infections, including SARS-CoV-2, remain a leading cause of childhood morbidity and mortality in low- and middle-income countries (LMICs), yet the underlying immune determinants of disease severity are poorly understood. The increased susceptibility to SARS-CoV-2 could be related to a decreased antibody or altered inflammatory response. We conducted a cohort study of South African children hospitalised with acute respiratory infections, and collected mucosal and serum samples over time. Nasopharyngeal aspirates (NPAs) or swabs were tested for viral pathogens by multiplex PCR. Antibody levels, neutralising capacity, and inflammatory proteome profiles were assessed. In the cohort (median age 7. 31 months, IQR 2. 9-31. 7), 67 children (54%) were SARS-CoV-2 positive at enrolment. Substantial baseline anti-spike IgG was detected in both SARS-CoV-2-positive (68% serum, 58% saliva) and negative (40% serum, 36% saliva) patients, irrespective of disease severity. Lower expression of salivary inflammatory proteins was associated with severe disease (p
| Concepts | Keywords |
|---|---|
| African | Acute |
| Biomarkers | African |
| Hospitalised | Antibody |
| Months | Cohort |
| Viral | Cov |
| Hospitalised | |
| Infections | |
| Inflammatory | |
| Lmics | |
| Mucosal | |
| Respiratory | |
| Sars | |
| Serum | |
| Severity | |
| South |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | Respiratory Tract Infections |