[Effectiveness of vaccination in high risk population].
Sánchez-Muñoz
Juan Francisco
JF
Saponi-Cortés
José María
JM
Costo-Campoamor
Alberto
A
D006801:Humans; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000401:mortality / Q000517:prevention & control*; D012307:Risk Factors; D013030:Spain
D007252:Influenza Vaccines