Lack of Induction of RBD-Specific Neutralizing Antibodies despite Repeated Heterologous SARS-CoV-2 Vaccination Leading to Seroconversion and Establishment of T Cell-Specific Memory... oleh Bernhard Kratzer, Doris Trapin, Pia Gattinger, Teresa Oberhofer, Al Nasar Ahmed Sehgal, Petra Waidhofer-Söllner, Arno Rottal, Ulrike Körmöczi, Katharina Grabmeier-Pfistershammer, Gerhard H. Kopetzky, Franz Tischer, Rudolf Valenta, Winfried F. Pickl