Comparing immunogenicity and efficacy of two different mRNA-based COVID-19 vaccines as a fourth dose; six-month follow-up, Israel, 27 December 2021 to 24 July 2022 Barda, Noam and Canetti, Michal and Gilboa, Mayan and Indenboim, Victoria and Asraf, Keren and Weiss-Ottolenghi, Yael and Amit, Sharon and Zibly, Daniel and Doolman, Ram and Mendelson, Ella and Harats, Dror and Freedman, Laurence S. and Kreiss, Yitshak and Lustig, Yaniv and Regev-Yochay, Gili, Eurosurveillance, 27, 2200701 (2022), https://doi.org/10.2807/1560-7917.ES.2022.27.39.2200701