Human Papillomavirus Is Dangerous—But a Vaccine Can Save You!

Human papilloma virus (HPV) is a virus that can cause disease in the skin and mucus membranes of both women and men. There are more than 100 types of HPV. While most of them cause harmless infections, some types of HPV are more harmful and can lead to cancers. HPV infection cannot be cured. The only solution is to prevent infection by vaccinating girls and boys at the age of 9–15. HPV vaccination prevents the infection and also stops the spread of the virus from one person to another. This article will help you to understand the basics about HPV, the diseases it causes, and why the HPV vaccine is an important solution.

Human papilloma virus (HPV) is a virus that can cause disease in the skin and mucus membranes of both women and men. There are more than types of HPV. While most of them cause harmless infections, some types of HPV are more harmful and can lead to cancers. HPV infection cannot be cured. The only solution is to prevent infection by vaccinating girls and boys at the age of -. HPV vaccination prevents the infection and also stops the spread of the virus from one person to another. This article will help you to understand the basics about HPV, the diseases it causes, and why the HPV vaccine is an important solution.

Figure Figure
The structure of HPV. HPV is composed of proteins that assemble themselves into starry shield shapes. Seventy-two Starry shields assemble to create the capsid, which encloses the viral DNA (illustrated by Susan Nasif).

WHAT IS HUMAN PAPILLOMAVIRUS?
The human papillomavirus, also known as HPV, is a virus that infects humans and causes "papilloma." The word papilloma is composed of "papilla," which means pimple, and "oma," which refers to an abnormal growth of cells, otherwise known as a tumor. HPV preferably infects cells of the skin and the mucous membranes. The skin is an organ,

MUCOUS MEMBRANE
The tissue that lines the inside of numerous organs, including the oral cavity, the nasal cavity, and the genitals.
with several tissue layers, that forms the natural protective barrier of a person's body. Mucous membranes are the tissues that line the inside of numerous organs, such as the mouth, the throat, and the genitals.
Viruses are invisible to the naked eye, but they can be observed using a powerful microscope. HPV has a round shape, and its diameter is nm ( nm = . cm). This is a million times smaller than a tennis ball! Some of the proteins that make up HPV combine to form a star-shaped shield, kind of like a star built from Lego ® . In total, starry shields assemble to create the round shape of HPV, which is called the capsid. The capsid contains the viral DNA ( Figure ) [ , ].

CAPSID
The protein structure that surrounds the genetic material of the virus, like a shell.

HPV COMES IN DIFFERENT FORMS AND SPREADS VIA DIFFERENT ROUTES
HPV is not just one virus. There are more than kinds of HPV, but most of them are rare and not dangerous. Each kind of HPV has a slightly di erent looking starry shield and therefore has unique characteristics. Scientists have given each type of HPV a number to identify it. Some types of HPV, like and , are very harmful for humans (called high-risk HPV) and can cause malignant lesions,

MALIGNANT LESION
An abnormal new growth of tissue/cells which usually develops rapidly and spreads to the whole body. It is life-threatening if it is not taken care of. leading to cancers in various parts of the body. Others, like and , are less dangerous (called low-risk HPV) and might create wounds, such as warts or condyloma (Figure ) [ ]. Condylomas are warts that WART An abnormal growth of cells, most frequently in the shape of a nipple or cauliflower.

CONDYLOMA
A wart located in the mucous membrane for example on the genitals or in the throat. are located in the mucous membrane of the body, for example in the kids.frontiersin.org January | Volume | Article |

Figure
Lesions associated with HPV infection. infected by HPV. Most people do not even notice the infection, but can still infect other people. Infections can happen in swimming pools or through skin-skin contact when you shake hands. When a mother is infected, she can transmit the virus to her baby during childbirth. HPV is also the most common sexually transmitted disease and can be passed on through close intimacy and sexual contact.  Figure From HPV infection to cervical cancer. The blue square shows the infection of a cell by HPV. In the lower part of the drawing, you see the evolution of the cervix cells from normal (green) to cancerous (red) cell formation (illustrated by Susan Nasif).

SYMPTOMS: FROM WARTS TO CANCER
although these are less common than cervical cancer, it is important to remember that men are also vulnerable to HPV infection and can also develop cancer.
Being infected by HPV does not mean that a person will definitely develop a tumor. This is good news, because HPV infection is the most common viral infection of the reproductive tract. To develop cancer, a person must be infected by a high-risk type of HPV and be infected for a long time, meaning that the person's body is not able to fight against the virus e ectively. To better understand the risks linked to HPV infection, if adolescents are infected, will clear the virus from their bodies and only will develop a serious disease, such as cervical cancer.
Sometimes, when a high-risk type of HPV infects human cells, the virus can mislead the immune system and maintain its infection. This long-standing infection is the first step in the potential development of cancer. The infection starts at the deepest layer of the skin or mucous membranes (see yellow triangle in Figure ). HPV disrupts the functioning of the cells it infects [ ]. After taking control of the cells, HPV can reproduce itself and invade more cells, from the deepest layers to the surface. Each infected cell displays an abnormal appearance that doctors and scientists can detect if they examine the cells using a microscope (Figure ).  Figure What is the HPV vaccine? Section illustrates a cell being infected by HPV and turning sick. Section illustrates the stages to create the vaccine against HPV, namely by using yeast cells to produce VLPs that mimic the appearance of HPV. Section illustrates a cell being infected by HPV. The immune system of the cell fights e ciently the virus thanks to the vaccine previously received (illustrated by Susan Nasif).

VACCINATION KEEPS US PROTECTED FROM HPV
HPV infection cannot be cured. The only solution is to prevent HPV infection from happening in the first place, through vaccination. Currently, the HPV vaccine can protect us against nine high-risk types of HPV: , , , ]. Therefore, the vaccine prevents most cases of HPV infection that can lead to serious health problems.
The HPV vaccine is made of reconstructed starry shields of the viruses, which cannot cause any harm to humans. Those shields are called virus-like particles (VLPs) because they look like the HPV virus but

VIRUS-LIKE PARTICLE
Small particle that appears like a certain virus since it contains proteins from the viral capsid. They do not contain viral genetic material and can therefore not cause an infection. They are usually synthesized in laboratories to mimic a virus, like in the HPV vaccine.
do not actually come from it. VLPs are created in laboratories using yeast cells (Figure ). When a person receives the vaccine, the immune system reacts against the VLPs and remembers them. If the person gets infected by HPV later, the immune system will remember the starry shield of the virus and immediately fight to eliminate the virus from the body.
Girls and boys should be vaccinated against HPV between and years old. Why so early? It is important that you get your first HPV vaccine before you get intimate with somebody you like, because the virus is easily transmitted from one person to another. The sooner you get vaccinated, the fewer shots you need: between and years old, you only receive two shots, whereas if you are between and years old, you need three shots to be protected. The pinch of the shot is worth it, do not you think? Although the vaccine is very safe and e ective, you might experience some mild side e ects, such as a sore spot, swelling, and redness where the shot was given. Headaches and nausea can also occur, but less frequently. Boys usually get tested when something strange appears on their genitals or if they find out their partner is infected. There is no Pap test for boys, but HPV can be detected using a laboratory technique that looks for the DNA of the HPV virus. When a wart is observed on the genitals of a girl or a boy, the doctor can collect the wart cells, which can then be tested in the lab to see if they contain HPV.

WHAT DID I LEARN? VACCINATION TO PROTECT MYSELF AND OTHERS!
HPV is very common. It is considered to be the most common sexually transmitted disease and men are equally infected than women. In most cases, infected people clear the virus from their bodies, but sometimes the immune system is not strong enough to fight it. Hence, some people develop serious health problem, such as cancer. Currently, no cure exist to get rid of this viral enemy, but we can protect ourselves with a vaccine.
The more people are vaccinated, the lower the risk of HPV infection will be. Spread the news to your friends, classmates, and family to create a chain of solidarity against HPV and decrease the transmission of the virus. Widespread immunization against HPV could reduce, and eventually even eliminate, cervical cancers and other diseases caused by HPV worldwide.

REFERENCES
. Song, D., Li, H., Li, H., and Dai, J. . E ect of human papillomavirus infection on the immune system and its role in the course of cervical cancer. Oncol. Lett.

CONFLICT OF INTEREST:
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
COPYRIGHT © Neunez, Nasif, Smeesters and Stevens. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

PIERRE R. SMEESTERS
Pierre Smeesters is a pediatrician working as the head of the pediatric department from the Academic Children's Hospital Queen Fabiola at the Free University of Brussels (ULB) in Belgium. He is also leading a research group in Microbiology and Infectious Disease at the Free University of Brussels. His research interests include translational research in Strep A, vaccination, new diagnostic tests, and societal issues related to childhood.

HILDE STEVENS
I am an Associate Professor at the Université Libre de Bruxelles. My research focuses on how people with various cultures and ways of working (e.g., academics or people in the pharmaceutical industry) could optimally collaborate to bring inventions from the lab to the patient much faster, and how patients in low-and middle-income countries also could get access to innovative therapies. I love telling stories to my children about bad bugs and how to fight them, and then we make paintings about it!