Human Papillomavirus (HPV) is a widespread group of over 200 viruses, some transmitted through sexual contact. While many HPV infections are harmless, certain types, including HPV 35, are classified as “high-risk” due to their potential to cause serious health issues.
Understanding HPV Type 35
HPV 35 is categorized as a high-risk HPV type, meaning it can lead to the development of certain cancers through cellular changes that may progress to malignancy. HPV types are broadly divided into cutaneous types, which affect the skin, and mucosal types, which infect the lining of the mouth, throat, respiratory tract, or anogenital area. HPV 35 is a mucosal type.
Transmission of HPV, including type 35, primarily occurs through direct skin-to-skin contact, most commonly during vaginal, anal, or oral sexual activity. The virus infects epithelial cells, found on the surfaces of the body and mucous membranes. Many individuals who contract HPV, including high-risk types like HPV 35, do not experience any symptoms, and their immune systems often clear the infection within one to two years.
Associated Health Risks
Persistent infection with high-risk HPV types, such as HPV 35, can lead to abnormal cell changes that may progress to cancer. While HPV 16 and 18 cause most HPV-related cancers globally, HPV 35 is a high-risk type, contributing to a smaller but significant percentage of cases. In certain populations, such as women of African ancestry, HPV 35 is more prevalent in cervical precancers and invasive cervical cancers, accounting for up to 10% of cases in Sub-Saharan Africa compared to about 2% worldwide.
HPV 35 is associated with several types of cancer, primarily affecting the anogenital region and oropharynx. These include cervical cancer, anal cancer, vaginal cancer, vulvar cancer, penile cancer, and oropharyngeal cancers (affecting the back of the throat and tonsils). The progression from initial infection to cancer is typically slow, often taking a decade or more for persistent infections to lead to cancerous changes.
Screening and Management
Detecting HPV infections and the cellular changes they cause involves specific screening methods. For individuals with a cervix, regular screening includes Pap tests and HPV tests. A Pap test involves collecting cervical cells to check for abnormal changes, while an HPV test detects the presence of high-risk HPV types in cervical cells. These tests can be performed together as a “cotest” or individually, with guidelines varying based on age and previous screening history.
If a Pap test shows abnormal cells or an HPV test is positive for a high-risk type, further evaluation may be recommended. This often involves a colposcopy, where a lighted magnifying instrument examines the cervix closely. During colposcopy, a biopsy may be performed to collect a tissue sample for microscopic examination to check for precancerous or cancerous cells. There is no specific cure for the HPV infection itself; instead, management focuses on monitoring and treating any precancerous lesions to prevent their progression to cancer. Treatment options for precancerous lesions include cryotherapy, laser ablation, or loop electrosurgical excision procedure (LEEP), which remove abnormal cells.
Preventing HPV Infection
The most effective method for preventing HPV infection, including high-risk types like HPV 35, is vaccination. HPV vaccines are highly effective, offering protection against the HPV types most commonly associated with cancers. Current vaccines, such as the 9-valent HPV vaccine, protect against nine HPV types: HPV 16, 18, 31, 33, 45, 52, and 58, which together account for a large percentage of cervical cancers. While HPV 35 is not directly covered by current vaccines, some studies suggest existing vaccines may offer some cross-protection against it.
In addition to vaccination, other preventive measures can help reduce the risk of HPV transmission. Consistent and correct use of condoms during sexual activity can lower the risk of infection, although condoms do not provide complete protection because HPV can infect areas not covered by a condom. Limiting the number of sexual partners and engaging in open communication about sexual health with partners also contribute to reducing exposure risk.