Protective antibodies and T cell responses to Omicron variant after the booster dose of BNT162b2 vaccine

• Published in: Cell Reports Medicine 2022-08, Vol.3 (8), p.100716-100716, Article 100716
• Main Authors: Naaber, Paul, Tserel, Liina, Kangro, Kadri, Punapart, Marite, Sepp, Epp, Jürjenson, Virge, Kärner, Jaanika, Haljasmägi, Liis, Haljasorg, Uku, Kuusk, Marilin, Sankovski, Eve, Planken, Anu, Ustav, Mart, Žusinaite, Eva, Gerhold, Joachim M., Kisand, Kai, Peterson, Pärt
• Format: Article
• Language: English
• Subjects: adverse effects; dynamics of the immune response; SARS-CoV-2 mRNA vaccine; spike RBD-ACE2 inhibition; T cell response
• ISSN: 2666-3791; 2666-3791
• DOI: 10.1016/j.xcrm.2022.100716

The high number of mutations in the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes its immune escape. We report a longitudinal analysis of 111 vaccinated individuals for their antibody levels up to 6 months after the third dose of the BNT162b2 vaccine. After the third dose, the antibody levels decline but less than after the second dose. The booster dose remarkably increases the serum ability to block wild-type or Omicron variant spike protein’s receptor-binding domain (RBD) interaction with the angiotensin-converting enzyme 2 (ACE2) receptor, and these protective antibodies persist 3 months later. Three months after the booster dose, memory CD4+ and CD8+ T cells to the wild-type and Omicron variant are detectable in the majority of vaccinated individuals. Our data show that the third dose restores the high levels of blocking antibodies and enhances T cell responses to Omicron. [Display omitted] •After the third BNT162b2 dose, the antibody levels decline slower than after the second•The protective antibodies persist for at least 3 months after the third dose•81% of individuals have T cell responses to Omicron at 3 months after third dose Naaber et al. monitor individuals vaccinated with BNT162b2 up to 6 months after the third dose. The S-RBD IgG levels decline but slower after the third than second dose. The booster restores the serum ability to block wild-type and Omicron RBD interaction with the ACE2 and boosts cellular immunity.