Effectiveness of ChAdOx1 nCoV-19 (Vaxzevria) primary series vaccine against SARS-CoV-2 beta and delta variants: a nationwide study. - Chemaitelly, Hiam; Ayoub, Houssein H.; Coyle, Peter; Tang, Patrick; Hasan, Mohammad R.; Yassine, Hadi M.; Al Thani, Asmaa A.; Al-Kanaani, Zaina; Al-Kuwari, Einas; Jeremijenko, Andrew; Kaleeckal, Anvar Hassan; Latif, Ali Nizar; et al. (BMC Infectious Diseases, 2025)