This study investigated the 12-month antibody dynamics in COVID-19 recovered individuals, focusing on the receptor-binding domain (RBD) of the spike (S) protein and nucleocapsid (N) protein. The study also aimed to identify clinical parameters correlated with declining antibody levels and to evaluate the prevalence and symptoms of Post-COVID Syndrome (PCS) after one year. Results showed stable anti-RBD/S1 antibody levels in unvaccinated individuals, a significant booster effect of vaccination, and a significant decrease in anti-N antibodies. A prediction model for antibody decline was developed using a random forest algorithm. PCS prevalence was 38.6% at 12 months, with an increase in cognitive impairments. Cell-free DNA (cfDNA) did not effectively differentiate between subjects with and without PCS.

Gerhards, C, Kittel, M, Ast, V, Bugert, P, Froelich, M.F, Hetjens, M, Haselmann, V, Neumaier, M, Thiaucourt, M