People under the age of 60 who initially received a vaccine from AstraZeneca should be given an mRNA vaccine at their second appointment. This is recommended by the German Standing Committee on Vaccination. However, up until now, there were no data available to indicate to what extent the human organism would react to such a mix-and-match vaccination and start to form antibodies. A team of researchers has now proven that the antibody response is much stronger with the mix-and-match vaccine than with two doses of the AstraZeneca vaccine.
Researchers at Technische Universität München (TUM), Helmholtz Zentrum München, Universitätsklinikum Erlangen and Universitätsklinikum Köln have now investigated immune response of mix-and-match vaccines within the framework of a retrospective scientific study. They took blood samples from 500 people who received a second vaccination with the mRNA vaccine from BioNTech/Pfizer nine weeks after their first AstraZeneca vaccine. The result: The neutralising antibody response was much higher in these people than in those who had received two doses of the AstraZeneca vaccine. The immune response to mix-and-match vaccines has proven to be just as good as the antibody response after two vaccinations with the mRNA vaccine from BioNTech/Pfizer. The study has now been published in the journal ’The Lancet Infectious Diseases’.
Based on the data they collected, the researchers have come to the conclusion that mix-and-match vaccines are a valid option. The combination of two different vaccines is even more effective than two doses of the AstraZeneca vaccine, and might be used, for example, in individuals with allergies or if there are bottlenecks with supplies. The researchers also hope that the mix-and-match vaccine will be a further building block that can be used to improve the overall effectiveness of the Covid-19 vaccination. However, more studies are required to confirm the safety and clinical effectiveness of using this and other mix-and-match vaccines.
The study was able to be carried out so quickly thanks to assistance from several different parties: the Bavarian State Ministry of Science and the Arts as part of the CoVaKo-2021 project and the FOR-COVID consortium, the German Centre for Infection Research (DZIF) and the vaccination network VACCELERATE (funded by the EU programme Horizon 2020). The aim of CoVaKo-2021 and FOR-COVID is for scientists to monitor the introduction of Covid-19 vaccinations in Bavaria. The study was mainly conducted by the three principal investigators Ulrike Protzer from Munich, Klaus Überla from Erlangen and Oliver Cornely from Cologne.
Bernd Sibler, Bavarian State Minister for Science and the Arts, emphasises: "The results of this study have a direct impact on our vaccination strategy. They help us to use vaccinations as effectively as possible and act as an important basis for political decisions regarding our vaccination strategy in the future. The work of our scientists at the Faculty of Medicine and the university hospitals is indispensable for finding a way out of the Covid-19 pandemic."
Heterologous prime-boost vaccination with ChAdOx1 nCoV-19 and BNT162b2
Matthias Tenbusch, Sofie Schumacher, Emanuel Vogel, Alina Priller, Jürgen Held, Philipp Steininger, Stephanie Beileke, Pascal Irrgang, Ronja Brockhoff, Jon Salmanton-García, Kathrin Tinnefeld, Hrvoje Mijocevic, Kilian Schober, Christian Bogdan, Sarah Yazici, Percy Knolle, Oliver A Cornely, Klaus Überla, Ulrike Protzer
The Lancet Infectious Diseases, 29 July 2021