Frontiers in Immunology (Jun 2021)

Antibody Responses to SARS-CoV-2 Following an Outbreak Among Marine Recruits With Asymptomatic or Mild Infection

  • Irene Ramos,
  • Carl Goforth,
  • Alessandra Soares-Schanoski,
  • Dawn L. Weir,
  • Emily C. Samuels,
  • Emily C. Samuels,
  • Shreshta Phogat,
  • Shreshta Phogat,
  • Michelle Meyer,
  • Michelle Meyer,
  • Kai Huang,
  • Kai Huang,
  • Colette A. Pietzsch,
  • Colette A. Pietzsch,
  • Yongchao Ge,
  • Brian L. Pike,
  • James Regeimbal,
  • Mark P. Simons,
  • Michael S. Termini,
  • Sindhu Vangeti,
  • Nada Marjanovic,
  • Stephen Lizewski,
  • Rhonda Lizewski,
  • Mary-Catherine George,
  • Venugopalan D. Nair,
  • Gregory R. Smith,
  • Weiguang Mao,
  • Maria Chikina,
  • Christopher C. Broder,
  • Eric D. Laing,
  • Alexander Bukreyev,
  • Alexander Bukreyev,
  • Alexander Bukreyev,
  • Stuart C. Sealfon,
  • Andrew G. Letizia

DOI
https://doi.org/10.3389/fimmu.2021.681586
Journal volume & issue
Vol. 12

Abstract

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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.

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