Emergence of SARS-CoV-2 Omicron lineages shifted antibody-mediated protection curves

Antibody dynamics models are analytical frameworks that probabilistically link changes in antibody titer timeseries to exposures. To date, antibody dynamics models have not been applied to SARS-CoV-2 datasets and have not incorporated observed exposures (i.e., from vaccination and positive PCR results) directly in their inference. We developed a bespoke framework that incorporates these features and applied it to data from the "Prospective Assessment of COVID-19 in a Community" (PACC) cohort. We used ELISA to measure serum antibody levels against Wuhan-1 spike (S) and nucleocapsid (N) proteins and inferred the level of protection from SARS-CoV-2 infection each antigen provided at different titers (protection curves). The S protection curve shifted when the Omicron lineage evolved, indicating that higher Wuhan-1 titers were required for protection. Age and exposure history did not shift the protection curves. This work highlights the utility of antibody dynamics frameworks to inform SARS-CoV-2 vaccination strategies.