[1] Fdn Fomento Invest Sanitaria & Biomed Comun Valen, Area Invest Vacunas, Valencia, Spain
[2] Ctr Salud Nazaret, Dept Clin Malvarrosa, Valencia, Spain
[3] Hosp Costa Sol, Dept Pediat, Malaga, Spain
[4] GISRS Global Influenza Surveillance & Response Sy, Ctr Nacl Gripe Valladolid, Valladolid, Spain