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Papillomavirus: preventing cancers by vaccinating young people, including boys

One year ago, the World Health Organization (WHO) launched a prevention campaign on the transmission and risks of HPV to encourage young men and women to be vaccinated. The virus called HPV is responsible for hundreds of thousands of cancers each year.

On this occasion, we interviewed Dr. Oceane Sorel, a virologist, who works with the United Nations to disseminate popularized and verified scientific information. She is notably active on Instagram (@TheFrenchVirologist) where, with humor, she helps fight misinformation.

What is HPV and how is it transmitted?

Human papillomavirus also known as HPV is a family of viruses that infect humans. There are more than 150 different types of HPV, about 40 of which are transmitted through sexual contact. Some of these HPVs (but not all!) are said to be “high-risk oncogenic” and can cause cancers such as cervical, penile, anal or oropharyngeal cancers… About 600,000 new cases of cancer per year are attributed to HPV worldwide, including cervical cancer.

HPV is highly contagious and is transmitted by contact with the skin or mucous membranes, particularly during sexual contact with or without penetrative sex. Simple skin-to-skin or genital contact is sufficient, so condoms do not provide complete protection against HPV infection.

How do I know if I have HPV, are there any signs of infection?

HPV infection is often asymptomatic and transient, meaning that the immune system ends up clearing the infection in most cases. Most men and women will be infected with HPV during their lifetime. Some transient infections can cause lesions in the cervix, but in 85% of cases, these abnormalities disappear spontaneously after a few months or years when the immune system eventually gets rid of the virus. In some cases, when a high-risk oncogenic HPV persists in the body, it can cause cancer in women (mainly cervical cancer, but also vulvar, vaginal, anal or oropharyngeal cancers) and men (penile, anal and oropharyngeal cancers).

How can HPV lead to cervical cancer? Is it systematic?

In the context of persistent infection with an oncogenic HPV and when the immune system has not been able to clear the infection, abnormal cells can appear in the cervix which can lead to pre-cancerous lesions and then turn into cancer. This progression is slow and takes several years (approximately 10-20 years between the time of infection and the development of cancer).

What are the risk factors for developing cervical cancer?

The main risk factor is infection with one or more of the 14 types of HPV that can cause cancer. Among them are HPV 16 and 18, which are responsible for about 70% of cervical cancers.

Other factors significantly increase the risk of developing cervical cancer such as sexual intercourse at an early age, multiple sexual partners, smoking, prolonged use of the oral contraceptive pill, immunosuppression, Chlamydia infections, multiple full-term pregnancies…

How can cervical cancer be prevented and detected? How often should I be tested?

Since 2006, there are vaccines that are recommended for young adolescents to prevent HPV infections and thus protecting them from developing cancers linked to these viruses. HPV vaccination is a primary prevention method against cervical cancer, but it is not sufficient to prevent 100% of cervical cancers. Therefore, vaccination does not replace cervical cancer screening.

In France, regular screening for cervical cancer is recommended for all women aged 25 to 65 (vaccinated or not) through collecting a few cells and mucus from the cervix to detect the presence of the virus (HPV test) or the presence of abnormal cells (cervical cytology also called Pap test). For more information about the types of tests and recommended intervals, consult your doctor.

Why is HPV testing not recommended for women under 30?

In France, cytology screening is recommended for women as young as 25 years old to detect the presence of abnormal cells. However, before the age of 30, HPV testing is not recommended because HPV infections are very common in young people. The peak of HPV infection occurs shortly after becoming sexually active. However, most of these infections are transient and disappear after a few months when the immune system eventually clears the infection. HPV testing in young women under 30 years of age would result in a significant number of unnecessary tests and potentially invasive treatments that could increase the risk of complications in future pregnancies when most of these infections would have resolved on their own without treatment.

Are there multiple vaccines? Why are there different vaccines? How effective are they?

There are 3 vaccines: Cervarix, Gardasil and Gardasil9 and all of them protect against HPV 16 and 18 which are responsible for most HPV-related cancers. Gardasil and Gardasil9  further protect against several HPVs that can cause genital warts. Finally, Gardasil9, which has replaced its predecessor Gardasil on the market, also targets other additional HPVs that are responsible for an additional 20% of cervical cancers. When given before the first sexual contact, HPV vaccines are more than 90% effective in preventing the targeted-HPV related infections.

HPV / Papillomavirus infographic

Who should be vaccinated and when?

In France, the High Authority of Health recommends vaccinating against HPV:

– All kids: Girls and boys aged 11 to 14 years according to a 2-dose schedule.

– A catch-up immunization is possible for all adolescents and young adults from 15 to 19 years of age according to a 3-dose schedule.

– Vaccination recommendation can be extended to 26 years for men who have sex with men.

Does the vaccine have any known side effects?

The reported side effects of HPV vaccines are overall classic side effects of the initiation of the immune response such as pain at the injection site, fever, fatigue, etc. Recent studies have found no link between vaccination and the development of autoimmune diseases.

Is it possible to be vaccinated against HPV after the first sexual intercourse?

Yes, up to a certain age. However, the vaccine effectiveness drops to 50-60% if it is given after the first sexual contact because the peak of HPV infection occurs shortly after becoming sexually active, hence the importance of age at the time of vaccination.

Should I get tested if I’m vaccinated?

Yes, vaccination is a primary layer of protection against cervical cancer, but no vaccine is 100% effective and vaccines do not protect against all types of oncogenic HPV and therefore are not sufficient to prevent all cervical cancers. In other words, vaccination does not replace regular cervical cancer screening.

Should boys get vaccinated too?

HPV vaccination has recently been extended to boys in France and in other countries around the world for several reasons. First, 4 out of 10 HPV-related cancers occur in men, and vaccination can prevent most HPV-related cancers in men. Indeed, in men, HPV infections can cause genital warts, penile, anal and oropharyngeal cancers. In addition, vaccination of boys protects girls from HPV infections. Finally, gender-neutral vaccination can help prevent the spread of HPV in the population and could ultimately lead to the eradication of high-risk oncogenic HPVs.

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