CD79A and COVID-19: Guerrieri et al. 26, using the same technique, and Varadhachary et al. 27, using a different approach, also showed a large variation in the salivary IgA titre in pre-vaccinated and pre-COVID-19 saliva samples, although they found significantly lower levels compared to those observed in COVID-19 vaccinated and COVID-19 PCR-confirmed individuals, respectively.