Vaccino anti HPV: cos'è? è sicuro? come funziona? perchè è importante vaccinare anche i ragazzi?

A systematic review of 138 studies confirms the effectiveness of the HPV vaccine in reducing cervical lesions and other HPV-related diseases in women and men worldwide. Vaccination against HPV leads to a reduction in the rates of high- and low-grade cervical lesions, as well as a reduction in some HPV-related non-cervical diseases, in both women and men. This is according to a meta-analysis published in the Expert Review of Vaccines, which examined the field effectiveness and global impact of human papillomavirus (HPV) vaccination with the quadrivalent recombinant vaccine (types 6, 11, 16, and 18). The systematic review, covering 138 studies published between March 1, 2016, and March 31, 2020, analyzes the impact and field effectiveness of the quadrivalent recombinant HPV vaccine implemented in immunization programs in 23 countries in Africa, Asia, Europe, Australia, South America, and North America. The new systematic review, which updates data from a previous review published in 2016, allowed for the assessment of the real-world impact of HPV vaccination on precancerous and related abnormal cervical lesions, genital warts (benign lesions), and HPV infection. Most of the countries included in the analysis used the quadrivalent recombinant HPV vaccine, while others also used the bivalent HPV vaccine. Studies involving only the bivalent HPV vaccine were excluded. Clinical trials conducted with the two available vaccines (bivalent and quadrivalent) showed high efficacy against precancerous and cancerous lesions of the cervix, exceeding 90% in populations that were naïve at the time of enrollment, meaning they were negative for the HPV types contained in the vaccine. The greatest reductions were observed in the youngest age groups (14-17 years), with a reduction of up to 73% in precancerous cervical lesions among vaccinated women. The satisfactory data from over one hundred published studies, in addition to demonstrating the vaccine's efficacy in reducing infections caused by HPV types and related diseases, represent an important reminder to do more to extend vaccination to both men and women. Only in this way will it be possible to implement the global fight to reduce the incidence of certain cancers, such as cervical cancer, and HPV-related diseases. The review demonstrates how vaccinations are also useful in reducing the incidence of anogenital warts in women in the vaccination target age groups, with the most significant reductions, up to 88%, observed in the youngest age groups. Unfortunately, there is no routine screening recommended for the detection of HPV-related non-cervical cancers and diseases. However, a consistent overall decrease in the prevalence of anal infection in vaccinated men has been observed, with variability observed depending on the HPV type involved. Furthermore, one study observed a significant reduction in high-grade anal precancerous forms among vaccinated men who have sex with men compared to unvaccinated men. Finally, there appears to be a significant reduction in the occurrence of recurrent respiratory papillomatosis, a rare form of airway infection caused by the human papillomavirus, among vaccinated women. To ensure maximum vaccination effectiveness, the World Health Organization recommends vaccination before the onset of sexual activity, i.e., before any possible exposure to HPV infection, between the ages of 9 and 11. In Italy, the National Vaccination Prevention Plan provides free vaccination for all adolescents, not only girls but also boys, starting at age 12 in all regions with the quadrivalent recombinant HPV vaccine. In 2017, the 9-valent vaccine was introduced in Italy, gradually replacing the quadrivalent vaccine. In addition to containing the four HPV strains of the previous vaccine, it added five additional oncogenic strains, offering broader protection against HPV-related diseases. Furthermore, in Italy, vaccination with the HPV vaccine is also recommended for women aged 25 and over, in conjunction with the first cervical cytology screening (Pap test). Vaccination is also recommended for all women, in accordance with regional guidelines.