Effectiveness of an inactivated Covid-19 vaccine with homologous and heterologous boosters against Omicron in Brazil oleh Otavio T. Ranzani, Matt D. T. Hitchings, Rosana Leite de Melo, Giovanny V. A. de França, Cássia de Fátima R. Fernandes, Margaret L. Lind, Mario Sergio Scaramuzzini Torres, Daniel Henrique Tsuha, Leticia C. S. David, Rodrigo F. C. Said, Maria Almiron, Roberto D. de Oliveira, Derek A. T. Cummings, Natalie E. Dean, Jason R. Andrews, Albert I. Ko, Julio Croda