Human papillomavirus, commonly known as HPV, is a group of more than 200 related viruses that infect human skin and mucous membranes. It is one of the most common sexually transmitted infections worldwide, with most sexually active individuals contracting it at some point in their lives[1][2]. HPV viruses are small, containing circular double-stranded DNA, and they belong to the Papovaviridae family[2].
HPV types are broadly classified into two categories based on their health risks: low-risk and high-risk types. Low-risk HPV types, such as HPV 6 and 11, typically cause benign conditions like genital warts and respiratory papillomatosis, which affects the airways. These types do not cause cancer[1][3]. High-risk HPV types, including HPV 16 and 18, are associated with the development of several cancers, most notably cervical cancer, but also anal, throat, vulvar, vaginal, and penile cancers[1][3][4].
The virus spreads primarily through intimate skin-to-skin contact, including sexual intercourse, oral sex, anal sex, and genital-to-genital contact without intercourse. Because HPV infections often do not cause symptoms, many people are unaware they are infected and can unknowingly transmit the virus to others[1][5]. The immune system clears most HPV infections naturally within one to two years, but in about 10% of cases, the infection persists for longer than two years, increasing the risk of developing cancer[5].
Cervical cancer is the most well-known and studied cancer caused by HPV. It develops when persistent infection with high-risk HPV types leads to abnormal changes in the cells of the cervix, the lower part of the uterus that opens into the vagina. These abnormal cells can progress to precancerous lesions and eventually invasive cancer if left untreated[3]. Cervical cancer often takes many years, sometimes decades, to develop after the initial HPV infection[5].
Detection of HPV and cervical cancer risk is commonly done through cervical screening tests. The Pap smear test can identify abnormal cervical cells, while HPV DNA tests can detect the presence of high-risk HPV types in women aged 25 or older. Early detection allows for treatment of precancerous changes before they develop into cancer[2].
There is no cure for HPV itself, but treatments exist for the symptoms and complications caused by the virus. Genital warts can be treated with medications or removed surgically, though they may recur. Precancerous cervical lesions can be treated with procedures such as cryotherapy (freezing), loop electrosurgical excision procedure (LEEP), or cone biopsy to remove abnormal cells[2].
Prevention of HPV infection and its consequences is possible through vaccination and safe sexual practices. HPV vaccines, such as the nonavalent vaccine Gardasil 9, protect against nine HPV types, including the most common high-risk types (16, 18) and low-risk types (6, 11). This vaccine can prevent approximately 90% of cervical cancers and also protects against other HPV-related cancers[3]. Vaccination is most effective when given before individuals become sexually active. Other preventive measures include abstinence, limiting the number of sexual partners, and consistent condom use, although condoms do not provide complete protection against HPV transmission[1][5].
HPV is also linked to cancers beyond the cervix. Recent research has shown that high-risk HPV types, especially HPV 16, contribute to head and neck cancers, including cancers of the throat, tonsils, and tongue. These cancers were previously thought to be mainly caused by tobacco and alcohol use, but HPV infection is now recognized as a significant factor[4].
In summary, HPV is a widespread virus with many types, some of which cause benign warts and others that can lead to serious cancers, particularly cervical cancer. Persistent infection with high-risk HPV types is the main cause of cervical cancer, which develops over many years. Screening and vaccination are key tools in preventing HPV-related diseases. Although there is no cure for HPV infection itself, medical treatments can manage symptoms and precancerous changes effectively.
Sources:
[1] Thomson Medical: Human Papillomavirus (HPV): Symptoms, Causes, Prevention, and Treatment
[2] Britannica: Human papillomavirus (HPV) | Description & Diseases
[3] PMC – National Center for Biotechnology Information: Unveiling the burden of human papillomavirus infection and risk
[4] Dr. Amit Chakraborty Blog: HPV and Head & Neck Cancers: Myths vs Facts
[5] Children’s Hospital of Philadelphia Vaccine Education Center: Human Papillomavirus: The Disease & Vaccines
