1. Medical and Scientific Affairs, Pfizer Vaccines, New York, NY 10017, USA
2. Medical and Scientific Affairs, Pfizer Vaccines, 75668 Paris, France
3. Center for Public Health, Medical University of Vienna, 1090 Vienna, Austria
4. Center for Virology, Medical University of Vienna, 1090 Vienna, Austria
5. Medical and Scientific Affairs, Pfizer Vaccines, 1210 Vienna, Austria