1. Infectious Diseases Unit; Infanta Sofía Hospital; Madrid Spain
2. National Epidemiology Center; Madrid Spain
3. Ramón y Cajal Hospital; Madrid Spain
4. Virgen del Rocío Hospital; Sevilla Spain
5. Son Espases Hospital; Palma de Mallorca; Spain
6. Donostia Hospital; San Sebastián Spain
7. La Paz University Hospital; Madrid Spain
8. Navarra Hospital; Pamplona Spain
9. Miguel Servet Hospital; Zaragoza Spain