& Sadoff, J. et al. Interim results of a phase 1-2a trial of Ad26.COV2.S covid-19 vaccine.N. Engl. J. Med. 384, 1824–1835 (2021). 25. Zhao, H. et al. Seroprevalence of neutralizing antibodies against human adenovirus type-5 and chimpanzee adenovirus type-68 in cancer patients. Front Immunol.