HPV (Human Papillomavirus) is one of the most far-reaching viruses that has managed to spread among humans. Transmitted most often sexually, it is estimated that up to 45 years of age, 80% of the sexually active population will have, at some point in their lives, become infected with it.
In the vast majority of cases, an HPV infection is cleared by the immune system without causing any symptoms. In the few times when this does not happen, HPV can cause the appearance of genital warts and, in the worst case scenario, various types of cancer, such as cervical, penis, vulva, anus, mouth and throat.
Because it causes infections without any symptoms and is transmitted through friction between skins, HPV is known to be one of the STIs (sexually transmitted infections) that circulate even among people who use condoms consistently. After all, the condom does not cover the entire body surface of an individual.
Only with the recommendation to use condoms, HPV spread through the Brazilian population, and one of the results of this, according to the Global Cancer Observatory of the WHO (World Health Organization), there are more than 17 thousand cases of cervical cancer diagnosed every year in the country.
Fortunately, in addition to condoms, we also have vaccines for the prevention of HPV, which help the immune system to eliminate the virus after an infection occurs. By eliminating the virus from people’s bodies, the vaccine also promotes, in a very effective way, the reduction in the incidence of cancers related to HPV. This is what we can call a true cancer vaccine.
Maximum vaccine protection is obtained when doses are given before an HPV infection occurs in a person’s lifetime. Thus, vaccination is made available free of charge by the SUS (Unified Health System) for both boys and girls under 15 years of age.
Does this then mean that within a few years Brazil will have eradicated all cases of cancer caused by HPV? Unfortunately not. And the main reason for this anticlimax is the difficulty we find in achieving good vaccination coverage for children and young people.
According to data released in a report by the SBIm (Brazilian Society of Immunizations), since 2013, when the HPV vaccine was introduced to the PNI (National Immunization Program), the minimum vaccination coverage target of 80% has only been achieved by the first dose among the vaccines. girls (83.4%). For the second dose, however, it drops to 55.6%. Among boys, the scenario is even more worrying, with coverage of 57.9% and 36.4% for the first and second doses, respectively.
It would be completely unrealistic to imagine that we will be able to obtain any satisfactory reduction in cases of cancer caused by HPV if we do not complete the vaccination in even 4 out of 10 boys in Brazil. This becomes an even more impossible mission due to the growth in the country of anti-vaccine denial discourse, which disseminates false information about side effects caused by vaccines.
One piece of news, however, that came almost as a breath of fresh air in the last week was the change in the WHO recommendations on HPV vaccination. A group of immunization experts from the agency reviewed a number of new results from clinical trials published in recent years and concluded that, in children, incomplete vaccination, with only one dose, is already capable of inducing protection against HPV comparable to the regimen complete.
With this change, the same batch of vaccine doses will be able to immunize twice as many children, which is especially interesting in the poorest countries, precisely those most affected by HPV-related cancers.
For now, in Brazil the recommendations have not yet changed. We continue to apply 2 doses to boys and girls up to 14 years of age, and 3 doses to immunosuppressed people aged up to 26 years for men and up to 45 years for women.
While the Ministry of Health does not update the recommendations for HPV vaccines, we need to work on parents’ resistance to vaccinating their children, convincing them that the benefit will only be seen in the long term. And that when they grow up, these children will surely thank them for being vaccinated at the right time.
