1. Centre for Epidemiological Studies on HIV/STI in Catalonia (CEEISCAT), Institut Catala d'Oncologia (ICO), Agencia de Salut Publica de Catalunya (ASPC), Generalitat de Catalunya, Badalona, Spain
2. CIBER Epidemiología y Salud Pública (CIBERESP), Spain
3. Department of Paediatrics, Obstetrics and Gynaecology, and Preventive Medicine, Univ Autonoma Barcelona, Bellaterra, Cerdanyola, Spain
4. Microbiology Service, Fundacio Institut d'Investigacio en Ciencies de la Salut Germans Trias i Pujol, Hospital Universitari Germans Trias i Pujol, Univ Autonoma Barcelona, Badalona, Spain
5. Sexual and Reproductive Health Centre, ASSIR Esquerre, Barcelona, Spain
6. Sexual and Reproductive Health Centre, CAP Sant Fèlix, Sabadell, Spain
7. Sexual and Reproductive Health Centre, BSA, Badalona, Spain
8. Sexual and Reproductive Health Centre Mataró-Maresme, Mataró, Spain
9. Youth Health Centre for Contraception and Sexuality (CJAS), Barcelona, Spain
10. Youth Health Centre Hospitalet del LLobregat, Spain