Comparison of neutralizing antibody responses against SARS‐CoV‐2 in healthy volunteers who received the BNT162b2 mRNA or the AZD1222 vaccine: Should the second AZD1222 vaccine dose be given earlier?. Issue 9 (2nd June 2021) - Terpos, Evangelos; Trougakos, Ioannis P.; Karalis, Vangelis; Ntanasis‐Stathopoulos, Ioannis; Sklirou, Aimilia D.; Bagratuni, Tina; Papanagnou, Eleni‐Dimitra; Patseas, Dimitrios; Gumeni, Sentiljana; Malandrakis, Panagiotis; Korompoki, Eleni; Dimopoulos, Meletios A.