Publication date: May 25, 2026
The concept of immunity debt due to reduced circulation of RSV in adults is controversial. We questioned whether adults lost protective antibodies when RSV was not circulating in Houston during the SARS-CoV-2 pandemic. We studied 100 adults (mean age 49; range 21-82) from a longitudinal cohort: 50 SARS-CoV-2 seronegative and 50 SARS-CoV-2 infected. They were followed from March-2020 to April-2021, when RSV was not in circulation. Three serum samples were collected per adult during the observation period and were tested for neutralizing antibodies against four RSV/A and RSV/B strains, fusion protein (F) site competitive antibodies (CA), and natural killer cell antibody dependent cell cytotoxicity (NK ADCC). Antibody kinetics and decay were analyzed. Seronegative and infection groups exhibited similar geometric mean neutralizing antibody titers (GMTs) against RSV/A and RSV/B strains, warranting a single combined cohort. The neutralizing antibody titers against the RSV strains during the three visits were stable over a mean of 309 days. Comparable antibody kinetic stability and decay rates were observed for F site CA to site cD8, II and IV. NK ADCC activity was detected in 29 participants with no correlation to neutralizing or F site competitive antibodies. We detected remarkable stability in protective antibody levels in adults against RSV when it was not circulating in Houston. Immunity debt could not be ascribed to the adult population in our cohort. We identified Fc-mediated antibody effector function by NK ADCC in a minority of adults, but this did not correlate with protective antibodies.
| Concepts | Keywords |
|---|---|
| Adults | antibody responses |
| Houston | COVD-19 |
| Pandemic | immunity debt |
| Serum | RSV |
| SARS-CoV-2 |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | COVID-19 Pandemic |
| disease | MESH | strains |
| disease | MESH | ADCC |
| disease | MESH | infection |