Human papillomavirus (HPV) is considered the most common cause of sexually transmitted infection (STI) today. Some types of the pathogen are even responsible for triggering the development of cancer. To prevent contamination, the international recommendation is to vaccinate children and adolescents before the onset of sexual life, when they have not yet been exposed to the virus.
But that doesn’t mean that sexually active women and men don’t benefit from immunization – the vaccine is available on the private network for people outside the groups provided for in the National Immunization Program (PNI).
“Although all programs in the world are focused on the age group that has not yet started sexual activity, we know that it is extremely rare to be infected with the four most common types of the virus and not have the benefits of vaccination”, says the pediatrician and president from the Brazilian Society of Immunizations (SBIM), Mônica Levi.
There are more than 200 types of HPV cataloged by science so far, and not all of them are considered dangerous to health. Vaccines include the most common and serious strains — even if a person has already been infected, it is unlikely that they will develop protection against all aggressive variants of the virus and, therefore, immunization is recommended.
Like any vaccine, the formula of vaccines against HPV teaches the body to create a robust and personalized defense against the invader. Studies on the effectiveness of vaccines have shown a significant reduction in the rates of infection, pre-neoplastic diseases, cervical surgeries and invasive cervical cancer associated with the types of HPV prevented by immunizations.
The formula also helps prevent infected and previously treated patients from re-injuring after treatment. “There is a risk of infected cells being reactivated and the patient suffering a recurrence”, explains the doctor.
very common virus
It is estimated that 80% of people have contact with one of the versions of HPV throughout their lives. More than 90% of them eliminate the virus spontaneously, without developing symptoms or even suspecting that they have been contaminated – but these individuals are at risk of being reinfected.
For other people, the infection can have more serious consequences, causing genital warts or cervical cancer. The virus is also associated with cancer of the penis, vulva, vagina, anus and oropharynx. “Therefore, vaccination is important even for those who have already had an infection or injuries”, emphasizes Mônica.
Vaccination in Brazil
The PNI schedule is aimed only at girls and boys aged between 9 and 14 years, with two doses six months apart, aiming to offer protection before the onset of sexual life. It is known that most people are infected with HPV soon after the onset of sexual activity.
The Unified Health System (SUS) also offers immunization for immunocompromised people up to 26 years old or up to 45 years old depending on the cause of immunosuppression.
Women and men outside this age group or priority group can be immunized in the private network. The available vaccines are indicated in the package insert for use in all people aged 9 to 45 years. They must take three doses, with an interval of two months between the first and second, and six months for the third.
There are three vaccines against HPV licensed in Brazil. The bivalent HPV2, manufactured by GSK, covers types 16 and 18, but had its commercialization stopped in Brazil in 2021.
The quadrivalent HPV4, from MSD, with action against types 6, 11, 16 and 18, has been part of the public network’s calendar since 2014. And the ninth-valent HPV9, from MSD, which also includes types 31, 33, 45, 52 and 58, is only available on the private network.
Immunization below target
Data from a study by the Cancer Foundation released last Sunday (26/3) show that all Brazilian capitals and regions are vaccinating against HPV below the target established by the PNI and the World Health Organization (WHO).
The survey is based on vaccination records of girls between 9 and 14 years old, in the period from 2013 to 2021, and boys aged 11 to 14 years old, between 2017 and 2021. For them, vaccination coverage was 76% for the first dose and 57% for the second dose. For them, it is even lower: 52% and 36%, respectively.
The researchers estimate that, at the current rate, Brazil will not be able to reach the vaccination coverage target needed to eliminate the disease by 2030.
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