Induction of robust cellular and humoral immunity against SARS-CoV-2 after a third dose of BNT162b2 vaccine in previously unresponsive elderly

Herein, we compared SARS-CoV-2-specific antibody and T-cell responses to two doses of BNT162b2 mRNA in 51 vaccinees > 80 years old and 46 (20–53 years old) controls. The responses of the elderly were much lower and 10% non-responders were identified. Importantly, in four of them, a third vaccination raised the immune response to levels seen in responders after two vaccinations, thus implying that non-response is not fateful even in the elderly.