SARS-CoV-2 Antibody Kinetics Eight Months from COVID-19 Οnset: Persistence of Spike Antibodies but Loss of Neutralizing Antibodies in 24% of Convalescent Plasma Donors

Terpos, Evangelos; Stellas, Dimitris; Rosati, Margherita; Sergentanis, Theodoros N.; Hu, Xintao; Politou, Marianna; Pappa, Vassiliki; Ntanasis-Stathopoulos, Ioannis; Karaliota, Sevasti; Bear, Jenifer; Donohue, Duncan; Pagoni, Maria; Grouzi, Elisavet; Korompoki, Eleni; Pavlakis, George N.; Felber, Barbara K.; Dimopoulos, Meletios A.

Elucidating the characteristics of human immune response against SARS-CoV-2 is of high priority and relevant for determining vaccine strategies. We report the results of a follow-up evaluation of anti-SARS-CoV-2 antibodies in 148 convalescent plasma donors who participated in a phase 2 study at a median of 8.3 months (range 6.8-10.5 months) post first symptom onset. Monitoring responses over time, we found contraction of antibody responses for all four antigens tested, with Spike antibodies showing higher persistence than Nucleocapsid antibodies. A piecewise linear random-effects multivariate regression analysis showed a bi-phasic antibody decay with a more pronounced decrease during the first 6 months post symptoms onset by analysis of two intervals. Interestingly, antibodies to Spike showed better longevity whereas their neutralization ability contracted faster. As a result, neutralizing antibodies were detected in only 76% of patients at the last time point. In a multivariate analysis, older age and hospitalization were independently associated with higher Spike, Spike-RBD, Nucleocapsid, N-RBD antibodies and neutralizing antibody levels. Results on persistence and neutralizing ability of anti-SARS-CoV-2 antibodies, especially against Spike and Spike-RBD, should be considered in the design of future vaccination strategies.