Human papillomavirus, commonly known as HPV, is a widespread virus. It is one of the most common viral infections globally, with nearly all sexually active individuals encountering it at some point in their lives. Many people infected with HPV will not experience symptoms, as their immune system often clears the virus naturally.
Understanding Human Papillomavirus
HPV is a DNA virus belonging to the Papillomaviridae family. Over 200 distinct types of HPV have been identified. These types are broadly categorized into two groups based on their potential health implications: low-risk and high-risk HPV types.
Low-risk HPV types cause benign growths, such as common warts on the hands or feet, and genital warts. For instance, HPV types 6 and 11 are responsible for approximately 90% of genital warts. These low-risk types rarely lead to cancer.
In contrast, high-risk HPV types are linked to the development of certain cancers. HPV 16 and HPV 18 are the most common, together accounting for about 70% of all cervical cancers worldwide. Persistent infection with these types can lead to abnormal cell changes that may progress to cancer.
How HPV Spreads and Its Effects
HPV is highly contagious and primarily spreads through direct skin-to-skin contact, especially during sexual activity. This includes vaginal, anal, and oral sex, as well as other close genital-to-genital contact. HPV can be transmitted even when an infected person shows no visible symptoms.
Transmission can also occur through hand-to-genital contact or from a pregnant person to a newborn during childbirth. The virus lives in the surface layers of the skin and does not require the exchange of bodily fluids like semen or blood for transmission. Condoms offer some, but not total, protection, as they do not cover all exposed skin.
The most common visible manifestation of HPV infection is the development of warts. Genital warts, caused by low-risk HPV types, appear as small bumps that can be flat, cauliflower-like, or stem-like. They occur on the vulva, penis, scrotum, or around the anus. These warts are painless but may itch or feel tender.
A more serious effect of persistent high-risk HPV infection is the development of various cancers. HPV is responsible for almost all cases of cervical cancer. High-risk HPV types are also linked to cancers of the anus, penis, vulva, vagina, and certain types of head and neck cancers, particularly those affecting the oropharynx. Most HPV infections are transient and cleared by the immune system within one to two years, but persistent infections can lead to these more serious health issues.
Prevention and Care
Preventing HPV infection primarily involves vaccination. The HPV vaccine is recommended for routine vaccination at age 11 or 12, and can be started as early as age 9. It is also recommended for individuals through age 26. For adults aged 27 through 45, vaccination may be considered after discussion with a healthcare provider.
The HPV vaccine is given as a two-dose series for those who start before their 15th birthday, with the second dose administered 6 to 12 months after the first. Individuals aged 15 through 26 receive a three-dose series. This vaccine protects against the HPV types that cause most HPV-related cancers and genital warts.
Beyond vaccination, practicing safer sexual habits, such as consistent and correct condom use, can help reduce the risk of HPV transmission. Regular screening programs are also an important secondary prevention strategy. The Pap test, which looks for abnormal cell changes on the cervix, and the HPV test, which detects high-risk HPV types, are the main screening tools. Guidelines suggest starting Pap tests at age 21, and for individuals aged 25 to 65, a primary HPV test every five years is recommended, or a co-test combining both HPV and Pap tests every five years, or a Pap test alone every three years.
While there is no cure for HPV infection itself, the conditions it causes, such as warts and precancerous lesions, can be managed and treated. Genital warts can be treated with prescription topical medications, or through procedures like cryotherapy (freezing with liquid nitrogen), electrocautery (burning with an electrical current), surgical removal, or laser surgery. For precancerous cell changes on the cervix, treatments include cryosurgery, laser surgery, loop electrosurgical excision procedure (LEEP) which removes a thin layer of cervical tissue using an electrified wire, or cold knife conization, a surgical procedure that removes a cone-shaped piece of the cervix. These treatments aim to remove abnormal cells and prevent progression to cancer.