Efectividad de la vacuna antigripal en individuos de 50-64 años de edad durante una estación de baja concordancia antigénica entre las cepas de virus de la vacuna y las cepas circulantes del virus de la gripe: Colorado, Estados Unidos, 2003-2004

VE was 60% (43-72%) and 48% (21-66%) among those without and with high-risk medical conditions, respectively. VE was 90% (68-97%) and 36% (0-63%) against influenza-related hospitalization for persons without and with high-risk conditions, respectively.