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:10.3389/fcimb.2024.1231697

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

Front Cell Infect Microbiol. 2024 Mar 27:14:1231697. doi: 10.3389/fcimb.2024.1231697. eCollection 2024.

Authors

Maria Giulia Conti¹, Eva Piano Mortari², Raffaella Nenna¹, Alessandra Pierangeli³, Leonardo Sorrentino³, Federica Frasca³, Laura Petrarca¹, Enrica Mancino¹, Greta Di Mattia¹, Luigi Matera¹, Matteo Fracella³, Christian Albano², Carolina Scagnolari³, Martina Capponi¹, Bianca Cinicola¹, Rita Carsetti², Fabio Midulla¹

Affiliations

¹ Department of Maternal, Child Health and Urological Sciences, Sapienza University of Rome, Rome, Italy.
² B Cell Unit, Immunology Research Area, Bambino Gesù Children's Hospital, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy.
³ Laboratory of Virology, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy.

Abstract

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.

Keywords: COVID-19 vaccines; SARS-CoV-2; children; immunogenicity; mucosal immunity.

MeSH terms

Adult
Antibodies, Viral
COVID-19*
Child
Humans
Immunity, Mucosal*
Immunoglobulin A
Mucous Membrane
SARS-CoV-2
Vaccination

Substances

Immunoglobulin A
Antibodies, Viral

Grants and funding

The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This research was supported by EU funding within the MUR PNRR Extended Partnership initiative on Emerging Infectious Diseases (project no. PE00000007, INF-ACT); by Italian Ministry of Health COVID2020-12371817; by grant 5 per mille, 2021 to EPM and by a grant from Sapienza University of Rome (Progetti di ricerca 2020) to CS.