Frontiers in Cellular and Infection Microbiology (Mar 2024)

SARS-CoV-2–specific mucosal immune response in vaccinated versus infected children

  • Maria Giulia Conti,
  • Eva Piano Mortari,
  • Raffaella Nenna,
  • Alessandra Pierangeli,
  • Leonardo Sorrentino,
  • Federica Frasca,
  • Laura Petrarca,
  • Enrica Mancino,
  • Greta Di Mattia,
  • Luigi Matera,
  • Matteo Fracella,
  • Christian Albano,
  • Carolina Scagnolari,
  • Martina Capponi,
  • Bianca Cinicola,
  • Rita Carsetti,
  • Fabio Midulla

DOI
https://doi.org/10.3389/fcimb.2024.1231697
Journal volume & issue
Vol. 14

Abstract

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The anti-COVID-19 intramuscular vaccination induces a strong systemic but a weak mucosal immune response in adults. Little is known about the mucosal immune response in children infected or vaccinated against SARS-CoV-2. We found that 28% of children had detectable salivary IgA against SARS-CoV-2 even before vaccination, suggesting that, in children, SARS-CoV-2 infection may be undiagnosed. After vaccination, only receptor-binding domain (RBD)–specific IgA1 significantly increased in the saliva. Conversely, infected children had significantly higher salivary RBD-IgA2 compared to IgA1, indicating that infection more than vaccination induces a specific mucosal immune response in children. Future efforts should focus on development of vaccine technologies that also activate mucosal immunity.

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