AUTHOR=Ramos Irene , Goforth Carl , Soares-Schanoski Alessandra , Weir Dawn L. , Samuels Emily C. , Phogat Shreshta , Meyer Michelle , Huang Kai , Pietzsch Colette A. , Ge Yongchao , Pike Brian L. , Regeimbal James , Simons Mark P. , Termini Michael S. , Vangeti Sindhu , Marjanovic Nada , Lizewski Stephen , Lizewski Rhonda , George Mary-Catherine , Nair Venugopalan D. , Smith Gregory R. , Mao Weiguang , Chikina Maria , Broder Christopher C. , Laing Eric D. , Bukreyev Alexander , Sealfon Stuart C. , Letizia Andrew G. TITLE=Antibody Responses to SARS-CoV-2 Following an Outbreak Among Marine Recruits With Asymptomatic or Mild Infection JOURNAL=Frontiers in Immunology VOLUME=12 YEAR=2021 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.681586 DOI=10.3389/fimmu.2021.681586 ISSN=1664-3224 ABSTRACT=

We investigated serological responses following a SARS-CoV-2 outbreak in spring 2020 on a US Marine recruit training base. 147 participants that were isolated during an outbreak of respiratory illness were enrolled in this study, with visits approximately 6 and 10 weeks post-outbreak (PO). This cohort is comprised of young healthy adults, ages 18-26, with a high rate of asymptomatic infection or mild symptoms, and therefore differs from previously reported longitudinal studies on humoral responses to SARS-CoV-2, which often focus on more diverse age populations and worse clinical presentation. 80.9% (119/147) of the participants presented with circulating IgG antibodies against SARS-CoV-2 spike (S) receptor-binding domain (RBD) at 6 weeks PO, of whom 97.3% (111/114) remained positive, with significantly decreased levels, at 10 weeks PO. Neutralizing activity was detected in all sera from SARS-CoV-2 IgG positive participants tested (n=38) at 6 and 10 weeks PO, without significant loss between time points. IgG and IgA antibodies against SARS-CoV-2 RBD, S1, S2, and the nucleocapsid (N) protein, as well neutralization activity, were generally comparable between those participants that had asymptomatic infection or mild disease. A multiplex assay including S proteins from SARS-CoV-2 and related zoonotic and human endemic betacoronaviruses revealed a positive correlation for polyclonal cross-reactivity to S after SARS-CoV-2 infection. Overall, young adults that experienced asymptomatic or mild SARS-CoV-2 infection developed comparable humoral responses, with no decrease in neutralizing activity at least up to 10 weeks after infection.