HPV Genotype Reference Guide
Classifying the oncogenic risk and clinical significance of common Human Papillomavirus strains.
For more foundational information, please start with our Pillar Guide on HPV Prevention.
Human Papillomavirus (HPV) is a diverse family of over 200 genetically distinct viruses. They are categorized numerically based on the chronological order of their discovery. When discussing clinical virology, especially in the context of reproductive and sexual health, approximately 40 types that infect the mucosal epithelium are divided into two main categories based on their oncogenic (cancer-causing) potential.
The Interactive Genotype Database
Select an HPV type below to view its risk classification, vaccine coverage, and associated clinical manifestations.
Clinical Association: The most potent oncogenic strain. Responsible for ~50% of cervical cancers globally and the vast majority of HPV-positive oropharyngeal (head and neck) cancers, as well as anal, vaginal, and vulvar cancers.
Vaccine Coverage: Included in Gardasil 9, Gardasil (quadrivalent), and Cervarix.
Notes: Tends to persist longer than other types and integrates more readily into the host genome.
Clinical Association: The second most potent oncogenic strain. Responsible for ~20% of cervical cancers. Highly associated with adenocarcinoma, a type of cervical cancer that begins in the glandular cells and can be harder to detect early via Pap smear.
Vaccine Coverage: Included in Gardasil 9, Gardasil (quadrivalent), and Cervarix.
Notes: Faster progression from infection to cancer compared to Type 16.
Clinical Association: Primarily causes anogenital warts. Along with Type 11, it is responsible for approximately 90% of all genital wart cases. Also associated with recurrent respiratory papillomatosis (RRP).
Vaccine Coverage: Included in Gardasil 9 and Gardasil (quadrivalent). Not in Cervarix.
Notes: Very rarely associated with malignant transformation.
Clinical Association: Like Type 6, it primarily causes anogenital warts and RRP.
Vaccine Coverage: Included in Gardasil 9 and Gardasil (quadrivalent). Not in Cervarix.
Notes: Often co-infects with Type 6. High infectivity rate but benign clinical course.
Clinical Association: A significant contributor to cervical dysplasia (CIN 2/3) and cancer, accounting for ~4% of cervical cancers. Closely related phylogenetically to Type 16.
Vaccine Coverage: Included in Gardasil 9.
Notes: Often targeted in secondary screening protocols if 16/18 are negative but cytology is abnormal.
Clinical Association: Closely related to Type 18. Strongly associated with cervical adenocarcinoma. Accounts for ~5% of cervical cancers.
Vaccine Coverage: Included in Gardasil 9.
Notes: Some older vaccines offered cross-protection against 45 due to its genetic similarity to 18.
Clinical Association: Important high-risk types that collectively account for about 10% of cervical cancers. Type 52 is particularly prevalent in Asian populations, while 58 has high prevalence in Latin America and East Asia.
Vaccine Coverage: All three are included in Gardasil 9.
Notes: These types are frequently found in high-grade squamous intraepithelial lesions (HSIL).
Understanding Risk Categories
High-Risk (Oncogenic) Types
The International Agency for Research on Cancer (IARC) classifies specific HPV types as Group 1 carcinogens. The most critical are 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 73, and 82.
These types produce viral oncoproteins (E6 and E7) that, during a persistent infection, can disrupt the host cell cycle by binding to and inactivating critical tumor suppressor proteins (p53 and pRb). Over years or decades, this unchecked cellular proliferation can accumulate mutations leading to invasive cancer.
Low-Risk (Non-Oncogenic) Types
Types such as 6, 11, 40, 42, 43, 44, 54, 61, 70, 72, 81 are considered low-risk. While their E6 and E7 proteins can stimulate cell growth resulting in benign warts (papillomas), they lack the affinity to permanently disable the host's tumor suppressor mechanisms, meaning they rarely lead to cancer.