<p>Schematic showing the multiple levels of the <i>serosolver</i> model.</p>

(B) Infections are modelled as Bernoulli trials from the nfection probability model in (A), resulting in longitudinal neutralising antibody (nAb) titres. This example shows predicted antibody titres to variant X (blue) for a participant first infected with variant X and later with variant Y. (C) The model captures cross-reactive antibody response to all variants.

Shown here are nAb titres to variant Y (pink) over time, compared to variant X (blue, dotted), with sampling points for two longitudinal measurements indicated. (D) The antigenic map determines cross-reactivity between variants, here depicting the Euclidean distance between variants X and Y. (E–F) nAb titres measured against variants X (blue) and Y (pink) at the first (E) and second (F) sample collection. Created with Biorender.com.</p> <p>(PNG)</p>