Human Papillomavirus, or HPV, represents a large group of over 200 related viruses that are extremely common worldwide. While many people may contract HPV at some point in their lives, these diverse types are broadly categorized based on their potential to impact human health.
Low-Risk HPV Types
Low-risk human papillomavirus types rarely lead to cancer. These types cause the growth of benign lesions on the skin or mucous membranes. The most common manifestations of low-risk HPV infection include genital warts, which are soft, flesh-colored bumps that appear on or around the genitals and anus. These warts can vary in size and shape, sometimes appearing as single lesions or in clusters.
Beyond genital warts, low-risk HPV types can also cause non-genital warts, such as common warts found on the hands, or plantar warts that develop on the soles of the feet. These skin growths are harmless, though they can sometimes cause discomfort or itching. HPV types 6 and 11 are recognized as the primary culprits, accounting for over 90% of all cases of genital warts.
High-Risk HPV Types
In contrast to low-risk strains, high-risk HPV types can cause cancer. While infection is common, persistent infection raises concern for cellular changes, which can lead to the development of cancerous cells in various parts of the body.
High-risk HPV types are strongly linked to several cancers, including cervical, oropharyngeal (throat), anal, penile, vaginal, and vulvar cancers. Among these, HPV 16 and HPV 18 are responsible for approximately 70% of all cervical cancer cases. These two types also contribute to a large proportion of other HPV-related cancers.
Identifying HPV Types
Determining the specific type of HPV often involves distinct diagnostic methods, especially for cervical health. A Pap test, also known as a Pap smear, screens for abnormal cells on the cervix that could be caused by HPV infection. This test does not directly detect the virus itself but identifies cellular changes that may indicate a risk of developing cancer.
An HPV test, on the other hand, directly detects the virus’s genetic material. These tests are primarily used in cervical cancer screening to identify high-risk HPV types in cervical cells. Currently, there is no routine, commercially available test to detect HPV in men or to specifically identify low-risk HPV types that cause warts.
Prevention Targeting Specific HPV Types
Prevention strategies for HPV largely center on vaccination, which directly targets specific types of the virus. The HPV vaccine, such as Gardasil 9, offers protection against common and harmful HPV types. This vaccine specifically covers the two most common low-risk types, HPV 6 and HPV 11, which are responsible for the majority of genital warts.
The vaccine also provides protection against the high-risk types HPV 16 and HPV 18, which are implicated in many cervical and other HPV-associated cancers. Gardasil 9 further covers five additional high-risk HPV types (31, 33, 45, 52, and 58) that contribute to a notable percentage of these cancers.