"SAGE’s review concluded that a single-dose Human Papillomavirus (HPV) vaccine delivers solid protection against HPV, the virus that causes cervical cancer, that is comparable to 2-dose schedules. This could be a game-changer for the prevention of the disease; seeing more doses of the life-saving jab reach more girls.
SAGE recommends updating dose schedules for HPV as follows:
one or two-dose schedule for the primary target of girls aged 9-14
one or two-dose schedule for young women aged 15-20
Two doses with a 6-month interval for women older than 21"
https://www.who.int/news/item/11-04-2022-one-dose-human-papillomavirus-(hpv)-vaccine-offers-solid-protection-against-cervical-cancer