What you need to know about the HPV vaccine

Human papillomavirus (HPV) is the most common sexually transmitted infection, and 80% of women are infected with HPV during their lifetime. However, 90% of these infections resolve spontaneously and do not require treatment. Despite this, 630,000 cases of cancer are registered annually in the world, 570,000 of which occur in women caused by HPV.

HPV causes cancer of the vagina, vulva, anus, penis, mouth, and throat, especially cervical cancer. Despite a significant decrease in the number of cases of cervical cancer after routine smear tests, the number of cases of head and neck cancer is increasing, especially in men. Head and neck cancer is the number one HPV-related cancer in the United States.

There are about 140 types of HPV, and 40 of them can cause infection in the genital area. Of these, 12 (types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 and 59) are at higher risk for cervical cancer, and 8 of them (types 26, 53, 66, 67 , 68, 70, 73 and 82) are considered potentially risky. Types 16 and 18 are responsible for 70% of cervical cancers. Although types 6 and 11 do not cause cancer, they are responsible for 90% of genital warts and cause recurrent wart-like papillomatous disease of the larynx.

HPV vaccines

HPV vaccines are made from virus-like particles and cannot cause cancer because they do not cause infection. There are 3 types of vaccines on the market today:

1. Cervarix: provides immunity against types 16 and 18, responsible for 70% of cervical cancers.
2. Gardasil: This vaccine, which we use in Turkey, provides immunity against types 16, 18 and types 6 and 11, which cause 90% of warts.
3. Gardasil-9: This vaccine, which is not yet available in Turkey, provides immunity against 9 viruses, namely types 6, 11, 16, 18, 31, 33, 45, 52 and 58.

The World Health Organization recommends using any available vaccine. Although Cervarix only provides immunity against 2 types of viruses, post-vaccination antibody levels are higher than with other vaccines and immunity can be obtained against types 31, 33 and 45.

Who should get the HPV vaccine?

While the HPV vaccine is recommended for girls and boys aged 11-12 years, it can be given as early as 9 years of age. If vaccination was not carried out during this period, it is advisable to carry it out at the age of 13 to 26 years. Although higher antibody levels are achieved with early vaccination, there is no direct relationship between antibody levels and protection scores. Studies show that low levels of antibodies are sufficient in terms of protection.

The vaccine can also be given to people at high risk of HPV transmission after age 26, and in some countries it is usually given before age 45.

How many doses of the vaccine should be given?

Generally, 2 shots 6 or 12 months apart are recommended before the age of 15, and 3 shots after 15 years, although studies have shown that even one vaccine provides the same level of protection as 2 shots. For this reason, the vaccination committee of the World Health Organization recommends one vaccination at age 11-12 and 2 vaccinations for those who do so later. It is stated that in the near future it is possible to switch to a single vaccine in all age groups. In my practice, I recommend that all age groups get 2 vaccinations 6 months apart.

vaccine effectiveness

Because cancer is not ethically based on vaccine protection, the development of CIN 2 and CIN 3, which are precancerous lesions, is accepted as a target outcome. Studies have shown that vaccines reduce changes in CIN 2 and above by 90-98% in the 15-45 age group. In addition, it has been shown that the number of external genital and anal warts is reduced by 90% and the number of precancerous changes in the anus is reduced by 75-77%. The incidence of infections of the oral cavity and pharynx decreased by 93%. This level of protection is reduced to 47% in individuals with HPV infection prior to vaccination. For this reason, vaccination is recommended for individuals infected with HPV, but it should be noted that the vaccine provides protection only against types that the patient does not have and for which the vaccine provides immunity.

Screening for cervical cancer after vaccination

Vaccinators are now no different from other women and are encouraged to continue routine smear or HPV screening.

The duration of the vaccine

Although HPV vaccines have been shown to be effective up to 11 years of age in studies, they are said to likely provide lifelong protection and there is no need for additional vaccinations. Although antibody levels decrease with age, this is not thought to reduce protection, and protection is maintained even when antibodies are not detected.

Side effects

The most common side effects associated with vaccines are pain, redness, and allergic side effects. Although cases of low positional blood pressure and palpitations, regional pain and transient paralysis have been reported, they are extremely rare and a causal relationship has not been demonstrated.