Intramuscular vaccination against SARS-CoV-2 transiently induces neutralizing IgG rather than IgA in the saliva.

The mucosal immunity is crucial for restricting SARS-CoV-2 at its entry site. Intramuscularly applied vaccines against SARS-CoV-2 stimulate high levels of neutralizing Abs in serum, but the impact of these intramuscular vaccinations on features of mucosal immunity is less clear. Here, we analyzed kinetic and functional properties of anti-SARS-CoV-2 Abs in the saliva after vaccination with BNT162b2.

Omicron subvariants illustrate reduced respiratory tissue penetration, cell damage and inflammatory responses in human airway epithelia.

Introduction: To explore whether the reported lower pathogenicity in infected individuals of variant of concern (VoC) Omicron and its current subvariants compared to VoC Delta may be related to fundamental differences in the initial virus-tissue interaction, we assessed their ability to penetrate, replicate and cause damage in a human 3D respiratory model.

Methods: For this, we used TEER measurements, real-time PCR, LDH, cytokine and complex confocal imaging analyses.

Results And Discussion: We observed that Delta readily penetrated deep into the respiratory epithelium and this was associated with major tissue destruction, high LDH activity, high viral loads and pronounced innate immune activation as observed by intrinsic C3 activation and IL-6 release at infection sites.

Salivary antibodies induced by BA.4/BA.5-convalescence or bivalent booster Immunoglobulin vaccination protect against novel SARS-COV-2 variants of concern.

Currently, SARS-CoV-2 Omicron BA.5 subvariants BF.7 and BQ.

Antiviral drugs block replication of highly immune-evasive Omicron subvariants ex vivo, but fail to reduce tissue inflammation.

The identification of the SARS-CoV-2 Omicron variants BA.4/BA.5, BF.