Human papillomavirus (HPV) is a very common virus that can infect various areas of the body. There are over 100 types of HPV, with around 40 types that specifically infect the genital area. HPV is primarily transmitted through sexual contact and often resides in warm, moist areas like the mouth, throat, genitals, and anus.
Oral HPV
Many types of HPV can infect the mouth and throat, residing in the moist lining of the oropharynx (back of the throat, including the base of the tongue and tonsils). Oral HPV is passed through oral sexual contact, including vaginal, oral, and anal sex. The virus can also spread through open-mouth kissing if an infected person’s saliva enters the mouth. Once contracted, oral HPV tends to stay inside the oropharynx and is unlikely to spread to other areas of the body.
Around 10% of men and 3.6% of women have oral HPV, with HPV16 being the type most commonly found in cancers. Oral HPV is typically asymptomatic, though some people may notice mouth sores or small bumps known as papillomas.
Oral HPV is closely associated with some types of head and neck cancers, especially oropharyngeal cancer. The tonsils and base of the tongue are the areas most affected. Smoking and drinking alcohol in those with oral HPV significantly raises cancer risk.
Key facts about oral HPV:
- Resides in the moist lining of the throat and mouth
- Passed through oral sexual contact
- Often has no symptoms
- Linked to oropharyngeal cancer
Genital HPV
HPV is very common in the genital region. Around 79 million Americans are currently infected with HPV, with about 14 million becoming newly infected each year. HPV can infect the genitals of both males and females, residing in different areas:
Areas genital HPV resides in women:
- Vulva (outer part of the vagina)
- Vagina
- Cervix
- Anus
Areas genital HPV resides in men:
- Penis
- Scrotum
- Anus
- Urethra
Genital HPV is typically spread through vaginal, anal, and oral sex. Since condoms do not cover all infected areas, they do not fully protect against HPV. Many people with genital HPV don’t know they are infected since symptoms are often minimal or non-existent.
Genital HPV can cause genital warts, though the types that cause warts are different from the high-risk types that lead to cancer. Around 30% of genital cancers are linked to HPV, with cervical cancer being the most closely associated.
Key facts about genital HPV:
- Infects the genitals of both males and females
- Passed through sexual contact
- Often asymptomatic
- May cause genital warts or cancer
Cutaneous HPV
Many types of HPV only infect the outer layer of skin, residing in the basal epithelium cells of the epidermis. These are called cutaneous HPV types, which are responsible for common warts on hands and feet.
Cutaneous HPV is typically passed through direct skin-to-skin contact, or by touching objects used by an infected person such as towels, shoes, or gym equipment. Minor cuts or damages to the skin allow the virus entry. The virus then causes thickening and hardening of the skin, forming warty lesions.
Common warts often occur on hands and fingers, while plantar warts arise on the soles of the feet. Warts can also less commonly appear on the face, lips, chest, arms, and knees.
Cutaneous HPV may be more likely to spread to other areas of the infected person’s body through autoinoculation, such as scratching or biting warts and spreading virus particles. The immune system often clears the infection over time, causing warts to eventually disappear without treatment.
Key facts about cutaneous HPV:
- Causes common warts on hands and feet
- Passed through skin-to-skin contact
- Resides in outer layer of skin
- Usually clears from the body over time
Comparison of HPV Types
There are over 100 types of human papillomavirus, with different types tending to infect different areas. The virus resides in basal epithelial cells of the skin or mucous membranes.
| HPV Type | Location | Transmission | Symptoms |
|---|---|---|---|
| Oral HPV | Mouth/throat | Oral sexual contact | Often none, may have mouth sores or bumps |
| Genital HPV | Genitals, anus | Sexual contact | May be asymptomatic or cause genital warts |
| Cutaneous HPV | Hands, feet, face, chest, etc | Skin-to-skin contact | Causes common warts on skin |
While HPV resides in different areas, the underlying mechanism of infection is similar. The virus infects basal epithelial cells through micro-abrasions, evades the immune system, and replicates as infected cells divide and move up through the epithelial layers. Viral particles are shed to infect others.
HPV and Cancer
Some types of HPV are high-risk and can lead to cancer formation. When high-risk HPV lingers in epithelial cells for many years, it can eventually cause cellular changes and mutations that result in cancer:
- Oral HPV – Linked to oropharyngeal cancers, particularly at the base of the tongue and tonsils.
- Genital HPV – Associated with cancers of the cervix, vulva, vagina, penis, and anus.
- Cutaneous HPV – Very rarely linked to non-melanoma skin cancers in those with weakened immune systems.
HPV16 and HPV18 are the two main high-risk types responsible for around 70% of HPV-associated cancers. Preventive measures like vaccines, condoms, dental dams, and routine cancer screening are important to reduce HPV transmission and enable early treatment.
HPV Prevalence by Age and Gender
HPV is extremely common in sexually active adults, though prevalence varies by age and gender:
- HPV prevalence is highest in those under 25 years old soon after becoming sexually active.
- Over 50% of sexually active men and women in their early 20s have genital HPV.
- HPV rates significantly decline with age as the immune system clears the infection or viral DNA integrates into host cells.
- Around 20% of sexually active men and women in their 50s have genital HPV.
- Oral HPV follows a similar pattern, with prevalence declining with age.
Regarding gender differences:
- Men have a higher prevalence of both oral and genital HPV compared to women.
- The highest-risk HPV types are around 50% more common in men versus women.
- Higher HPV rates in men may reflect differences in immune response and sexual behaviors.
Table: HPV Prevalence by Age
| Age Range | Women | Men |
|---|---|---|
| 14-19 years old | 29.5% | 45.0% |
| 20-24 years old | 44.8% | 57.3% |
| 25-59 years old | 27.4% | 45.2% |
| 60-69 years old | 19.6% | 28.4% |
This table displays genital HPV prevalence by age range and gender, showing the decline in HPV rates with increasing age after early adulthood. Overall, HPV prevalence is higher in sexually active males compared to females.
HPV Vaccination
Safe and effective vaccines are available to prevent infection from certain high-risk HPV types that cause cancers and genital warts. The main HPV vaccines are:
- Gardasil: Protects against HPV types 16, 18, 6, 11 (quadrivalent vaccine)
- Gardasil 9: Protects against HPV types 16, 18, 31, 33, 45, 52, 58, 6, 11 (9-valent vaccine)
HPV vaccines are recommended for preteens starting at ages 11-12 to develop immunity well before sexual activity begins. The vaccines are given as a series of either two or three doses over 6-12 months. HPV vaccines provide long-lasting protection, though immunocompromised people may need booster shots.
The vaccines are most effective when given before any exposure to HPV. However, young adults who did not receive the vaccine as preteens can still benefit from vaccination up until their mid-20s. HPV vaccination together with routine cervical cancer screening greatly reduces HPV-associated disease burden.
Key Facts About HPV Vaccination:
- Recommended starting at ages 11-12
- Given as a 2-3 dose series over months
- Provides long-term immunity against cancer-causing HPV types
- Most effective when given before exposure to HPV
HPV Testing and Screening
Since HPV often has minimal symptoms, testing and screening are important to identify precancerous changes that may lead to cancer if left untreated. HPV testing is primarily used for cervical cancer screening, though it is sometimes performed with anal Pap tests as well.
Two main HPV tests are available:
- HPV DNA test – Detects current high-risk HPV infection by identifying genetic material of the virus.
- HPV E6/E7 mRNA test – Identifies HPV strains actively making cancer-causing proteins.
These tests for high-risk HPV types may be used together with a Pap smear, which screens for precancerous cell changes. HPV testing is approved for women 25 and over, in conjunction with cytology. Women who test positive may need additional follow-up testing.
Currently there are no recommended tests to screen for HPV-related cancers in the mouth/throat or penis. However, physical exams are important to detect any abnormal lesions or growths that could signal cancer.
Key Facts on HPV Testing:
- Used to identify high-risk HPV infections
- Primarily performed in cervical cancer screening
- May prompt further testing if results are abnormal
- No HPV tests approved to screen cancers of the mouth/throat or penis
HPV Treatment
There is currently no specific treatment to cure HPV or eliminate an active infection. However, the immune system usually clears HPV naturally within 1-2 years. Early intervention is key to prevent HPV complications:
- Genital warts – Treated with prescription medications, cryotherapy freezing, or surgery.
- Cervical dysplasia – Abnormal precancerous cells removed by procedures like LEEP or cone biopsy.
- HPV-related cancers – Treated with surgery, radiation, chemotherapy, targeted therapy.
Since HPV goes away on its own in most cases, conservative watchful waiting may be appropriate for mild disease. Stopping smoking, eating healthy, and managing stress support immune function against HPV.
For couples, condoms reduce HPV transmission risk during periods of active infection. However, condoms cannot fully protect against catching HPV or passing it on.
Key Facts on HPV Treatment:
- No treatment eliminates HPV infection
- Focuses on managing complications like genital warts and precancer
- Immune system often clears HPV naturally within 1-2 years
- HPV-linked cancers are treated with surgery, radiation, chemotherapy
Conclusion
HPV is a widespread virus that can reside in the epithelium of the skin and mucous membranes. Different HPV types tend to affect certain areas – oral, genital, or cutaneous. HPV is passed through direct sexual or skin-to-skin contact.
While HPV generally causes no symptoms and goes away on its own, some high-risk types are linked to cancers of the cervix, anus, vulva, vagina, penis, mouth, and throat. Vaccines now safely and effectively prevent infection from cancer-causing HPV strains.
Routine screening and follow-up testing are important for identifying precancerous changes that can be treated early before turning into cancer. Practicing safe sex, getting immunized, avoiding smoking, and eating healthy help minimize the risks from HPV.