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

• Published in: Frontiers in cellular and infection microbiology Vol. 14; p. 1231697
• Main Authors: Conti, Maria Giulia, Piano Mortari, Eva, Nenna, Raffaella, Pierangeli, Alessandra, Sorrentino, Leonardo, Frasca, Federica, Petrarca, Laura, Mancino, Enrica, Di Mattia, Greta, Matera, Luigi, Fracella, Matteo, Albano, Christian, Scagnolari, Carolina, Capponi, Martina, Cinicola, Bianca, Carsetti, Rita, Midulla, Fabio
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 27.03.2024
• Subjects: Cellular and Infection Microbiology; children; COVID-19 vaccines; immunogenicity; mucosal immunity; SARS-CoV-2; COVID-19 vaccines; SARS-CoV-2; children; immunogenicity; mucosal immunity
• ISSN: 2235-2988; 2235-2988
• DOI: 10.3389/fcimb.2024.1231697

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.