Differences in clinical features and mortality in very old unvaccinated patients (>= 80 years) hospitalized with COVID-19 during the first and successive waves from the multicenter SEMI-COVID-19 Registry (Spain)_

Ramos-Rincon, JM; Cobos-Palacios, L; Lopez-Sampalo, A; Ricci, M; Rubio-Rivas, M; Nunez-Rodriguez, MV; Miranda-Godoy, R; Garcia-Leoni, ME; Fernandez-Madera-Martinez, R; Garcia-Garcia, GM; Beato-Perez, JL; Monge-Monge, D; Asin-Samper, U; Bustamante-Vega, M;...