Human papilloma viruses (HPVs) are a group of about 200 similar viruses.
More than 40 types of HPV are transmitted through direct sexual contact. It is one of the most common sexually transmitted infections in the world and it is estimated that 50% - 75% of sexually active men and women have contracted genital HPV infection.
Types of sexually transmitted HPV fall into two categories:
- Low-risk HPV, do not cause cancer but can give rise to warts on the genitals and anus (for example types 6 and 11 are responsible for 90% of genital warts)
- High-risk HPV, can cause a variety of cancers, including cervical cancer (one of the most common cancers in women), cancer of the anus, vagina, penis, head and neck, including throat and tongue, and skin. About twelve high-risk HPV types have been identified. Two of these, 16 and 18, are responsible for most of the cancers caused by HPV. While most high-risk infections occur without ailments and go away within 1 to 2 years without consequences, some can persist for many years and lead to cellular changes that, if left untreated, can cause cancer.
Composition and use of the HPV vaccine
The European Medicines Agency (EMA) and the American Food and Drug Administration (FDA) have approved 3 vaccines, prepared from virus-like particles (VLPs), consisting of a protein present on the surface of the virus. Virus-like particles do not contain viral DNA, cannot infect cells, reproduce or cause disease.
All HPV vaccines protect against infection by types 16 and 18 which are responsible for 70% of cervical cancers, as well as being involved in other types of HPV cancer (Video).
In addition, there is a vaccine that also protects against types 6 and 11 and another, more recently authorized, which also defends against 5 other types of cancer, although less frequently than types 16 and 18.
These vaccines provide strong protection against new HPV infections but do not act on existing ones or diseases caused by HPV.
For this reason, vaccination does not replace the usual checks (pap tests) of the cervix which remain important and must continue to be carried out.Efficacy of the HPV vaccine
Efficacy of the HPV vaccine
The vaccine is "98 to 100% effective in preventing infections from the viruses it contains and in preventing the development of high-risk lesions caused by the types responsible for most cancers." According to recent studies, the protection of the vaccine exceeds 8 years and, therefore, to date there is no need for a booster dose. Other studies are underway that will provide more and more detailed information on the duration of protection.
Since the infection occurs very frequently at the beginning of sexual activity, vaccination of adolescents, before they can come into contact with the virus, represents the most effective and efficient way to avoid contagion (read the Hoax). in fact, the level of protection of the vaccine is significantly reduced in girls who have already started sexual activity (efficacy of 18%). In this case, it is considered more effective to adhere to periodic control programs (pap smear screening).When to get vaccinated
When to get vaccinated
The vaccine is administered, via an intramuscular injection, to male and female adolescents of 11 years of age, before the start of sexual activity. The vaccination schedule provides for the administration of two doses 6 months apart ( for people up to 13 or 14 years of age).
In older boys and girls the number of doses depends on age (read the Hoax).Side effects of the HPV vaccine
Side effects of the HPV vaccine
The most common adverse reactions observed were those occurring at the injection site, mainly erythema, pain and swelling (77.1% of vaccinated within 5 days following vaccination) and headache (16.6% of vaccinated). usually of mild or moderate intensity.Who does not have to get vaccinated
Who does not have to get vaccinated
Anyone who has had a major allergic reaction to any component of the vaccine or to a previous dose should not be vaccinated against HPV.
In addition, it is essential to inform your doctor if you have a yeast allergy (as the viral-like particles present in the tetravalent vaccine are produced by yeast cells) and / or latex (the piston cap of the bivalent vaccine is made of rubber of latex).
Vaccination must be postponed in people suffering from febrile, acute, severe illnesses. However, the presence of a "minor" infection, such as a mild upper respiratory tract infection or a slight rise in body temperature, is not a contraindication to vaccination.Where to find the vaccine
Where to find the vaccine
According to the provisions of the 2017-2019 National Vaccine Prevention Plan, vaccination is offered free of charge to adolescents, males and females, in the 12th year of life (11 years old) in all Italian regions.Bibliography
Steinbrook R. The potential of human papillomavirus vaccines. New England Journal of Medicine. 2006; 354: 1109–1112
Schiller JT, Castellsague X, Garland SM. A review of clinical trials of human papillomavirus prophylactic vaccines. Vaccine. 2012; 30 (Suppl 5): F123-138
Gee J, Naleway A, Shui I, et al. Monitoring the safety of quadrivalent human papillomavirus vaccine: Findings from the Vaccine Safety Datalink [Summary]. Vaccine. 2011; 29: 8279-8284In-depth link
Ministry of Health. Vaccinations. Teenagers 11-18 years
Centers for Disease Control and Prevention. Sexually transmitted diseases (English)