The cervical vaccine mainly prevents human papilloma virus, so it is also called HPV vaccine. the most ideal period for HPV vaccination is actually before the first sexual intercourse, because after having sex, 80%-90% of women may have already been infected with HPV virus, but the vaccine can also play a protective role for women who have already had sex, and the earlier the vaccination, the better the effect. The age of vaccination differs for each vaccine. The bivalent vaccine prevents HPV16 and HPV18, mainly for 9-25 years old; the quadrivalent vaccine prevents HPV6, 11, 16 and 18, mainly for 20-45 years old; the nine-valent vaccine prevents HPV6, 11, 16, 18, 31, 33, 45, 52 and 58, mainly for 16-26 years old. -26 years old. The age limit is not absolute and women who are over the age can also be vaccinated. However, the older you are, the less effective the vaccination will be.