Immune responses against SARS-CoV-2 variants after heterologous and homologous ChAdOx1 nCoV-19/BNT162b2 vaccination
Joana Barros‐Martins, Swantje I. Hammerschmidt, Anne Cossmann, Ivan Odak, Metodi V. Stankov, Gema Morillas Ramos, Alexandra Dopfer‐Jablonka, Annika Heidemann, Christiane Ritter, Michaela Friedrichsen, Christian Schultze‐Florey, Inga Ravens, Stefanie Willenzon, Anja Bubke, Jasmin Ristenpart, Anika Janssen, George Ssebyatika, Günter Bernhardt, Jan Münch, Markus Hoffmann, Stefan Pöhlmann, Thomas Krey, Berislav Bošnjak, Reinhold Förster, Georg M. N. Behrens
Abstract
Abstract Currently approved viral vector-based and mRNA-based vaccine approaches against coronavirus disease 2019 (COVID-19) consider only homologous prime-boost vaccination. After reports of thromboembolic events, several European governments recommended using AstraZeneca’s ChAdOx1-nCov-19 (ChAd) only in individuals older than 60 years, leaving millions of already ChAd-primed individuals with the decision to receive either a second shot of ChAd or a heterologous boost with mRNA-based vaccines. However, such combinations have not been tested so far. We used Hannover Medical School’s COVID-19 Contact Study cohort of healthcare professionals to monitor ChAd-primed immune responses before and 3 weeks after booster with ChAd ( n = 32) or BioNTech/Pfizer’s BNT162b2 ( n = 55). Although both vaccines boosted prime-induced immunity, BNT162b2 induced significantly higher frequencies of spike-specific CD4 + and CD8 + T cells and, in particular, high titers of neutralizing antibodies against the B.1.1.7, B.1.351 and P.1 variants of concern of severe acute respiratory syndrome coronavirus 2.