COVID-19 IgG seropositivity and its determinants in occupational groups of varying infection risks in two Andean cities of Ecuador before mass vaccination. - Leon-Rojas JE; Arias-Erazo F; Jiménez-Arias P; Recalde-Navarrete R; Guevara A; Coloma J; Martin M; Chis Ster I; Cooper P; Romero-Sandoval N (PloS one, 2024)