Modelling the association between neutralizing antibody levels and SARS-CoV-2 viral dynamics : implications to define correlates of protection against infection

• DOI: 10.1101/2023.03.05.23286816
• Publication Date: 2023-03-08T19:55:14Z
• Authors: Guillaume Lingas; Delphine Planas; Hélène Péré; Darragh Duffy; Isabelle Staropoli; Françoise Porrot; Florence Guivel-B...; Nicolas Chapuis; Camille Gobeaux; David Veyer; Constance Delaugerre; Jérôme Le Goff; Prunelle Getten; Jérôme Hadjadj; Adèle Bellino; Béatrice Parfait; Jean-Marc Treluyer; Olivier Schwartz; Jérémie Guedj; Solen Kernéis; Benjamin Terrier

AbstractBackgroundWhile anti-SARS-CoV-2 antibody kinetics have been well described in large populations of vaccinated individuals, we still poorly understand how they evolve during a natural infection and how this impacts viral clearance.MethodsFor that purpose, we analyzed the kinetics of both viral load and neutralizing antibody levels in a prospective cohort of individuals during acute infection by Alpha variant.ResultsUsing a mathematical model, we show that the progressive increase in neutralizing antibodies leads to a shortening of the half-life of both infected cells and infectious viral particles. We estimated that the neutralizing activity reached 90% of its maximal level within 8 days after symptoms onset and could reduce the half-life of both infected cells and infectious virus by a 6-fold factor, thus playing a key role to achieve rapid viral clearance. Using this model, we conducted a simulation study to predict in a more general context the protection conferred by the existence of pre-existing neutralization, due to either vaccination or prior infection. We predicted that a neutralizing activity, as measured by ED50>103, could reduce by 50% the risk of having viral load detectable by standard PCR assays and by 99% the risk of having viral load above the threshold of cultivable virus.ConclusionsThis threshold value for the neutralizing activity could be used to identify individuals with poor protection against disease acquisition.