9-valent HPV Vaccine for HPV 9-valent HPV vaccine is known as quite effective in building immunity against this virus. It is the only vaccine available in the US where it was approved in 2014. This vaccine decreased the risk of various HPV-related cancers and pre-cancers in both men and women. Children and adolescents aged up to 15 years need 2 doses while older adolescents and young adults aged 15-45 years need 2-3 doses within 6 months. WHO recommends vaccination against HPV 16 and 18.