Author:
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
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.