Nearly ten thousand young adults had an injection against the human papillomavirus (HPV) on Saturday on HPV Awareness Day. But what exactly is HPV?
Nine-year-old girls have been invited for an HPV vaccination since 2010, while boys only received it last year. RIVM therefore started a catch-up campaign in which everyone from 1996 or later can be vaccinated against the virus free of charge in 2023. But what exactly is HPV and what does the vaccine do?
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Warts and cancer
The human papillomavirus (HPV) is a group of viruses that causes warts, usually on the hands and feet. Of the 200 different types of HPV, about 40 viruses infect the genital regions and can therefore be transmitted through sex. HPV is one of the most common causes of STIs (sexually transmitted diseases); about 80 to 90 percent of sexually active people become infected at least once. Usually this does not cause any symptoms and our immune system clears the virus quickly.
However, symptoms do occur in 1 in 10 infections with the sexually transmitted HPV. Some types (especially 6 and 11) then cause genital warts, and are called low-risk HPV. Other types, such as 16 and 18, are high-risk variants and can cause cancer 10 to 15 years after infection.
Almost all cervical cancers are caused by HPV. But tumors can also arise in the vagina, labia, anus, penis and in the mouth and throat. According to the RIVM, 1100 women and 400 men get cancer every year due to infection with HPV.
Anti-cancersystemen
Infection usually occurs during vaginal or anal sex, but can also occur through intimate skin-to-skin contact. The virus enters the cells through small wounds in the skin or in the mucous membrane of the mouth, throat or cervix.
In those cells, high-risk variants of HPV produce the proteins E6 and E7. They reduce the effectiveness of the body’s built-in anti-cancer systems. They bind to the proteins p53 and Rb, which normally ensure that body cells die as a precaution if they grow abnormally or suffer DNA damage. Due to the binding with E6 and E7, they cannot do their job properly and the risk of cancer increases.
Significant decrease
The vaccine protects 95 percent against HPV infections with types 16 and 18, the two variants that most often cause cancer. That protection lasts at least 10 years, probably longer. Because the vaccine has not been around that long, the duration of protection is not yet known. The jab works less well against other high-risk variants. But these are also less likely to cause cancer.
The protection against HPV arises because the vaccine trains the immune system for a future infection. The shot contains a number of harmless virus components of types 16 and 18 and the body produces antibodies against them. In the event of an infection, the antibodies therefore quickly recognize the virus and clear it up.
It is clear that the vaccine prevents HPV infection. But because it can take 10 to 15 years before an infection leads to cancer, there are still few large-scale studies that look at whether a vaccination actually prevents cancer. Yet studies from Sweden (2020) and the United Kingdom (2021) have already found a significant reduction in the number of cervical cancer cases. The vaccine seems to be most effective at an early age, before someone becomes sexually active. According to the British study, children who get an HPV shot before the age of twelve have an almost 90 percent lower risk of cervical cancer. But it can also be useful at a later age; it is quite possible that someone is sexually active, but has not yet been infected with type 16 or 18.
Sources: RIVM, CDC, National Immunization Program, The Journal of Dermatology, Microbiology and Molecular Biology Reviews