The lung ultrasound ¿Rule of 7¿ in the prognosis of COVID-19 patients: Results from a prospective multicentric study Yale Tung-Chen; Adriana Gil-Rodrigo; Ana Algora-Martín; Rafael Llamas-Fuentes; Pablo Rodríguez-Fuertes; Raquel Marín-Baselga; Blanca Alonso-Martínez; Elena Sanz Rodríguez; Pere Llorens Soriano; José-Manuel Ramos-Rincón;