HPV, or human papillomavirus, is an extremely common cause of sexually transmitted diseases. Globally, almost all sexually active people are at risk of contracting HPV at some point in their lives.
Human papillomavirus (HPV) is a group of viruses that infect cells in the skin and mucous membranes of humans and belongs to the papillomavirus family. These viruses have an extremely high species diversity, and different HPV types can cause varying degrees of disease, from harmless skin warts to infections in the genital area, and may even lead to cancer.
Types of HPV
There are more than 100 types of HPV, which are divided into two main categories:
Low-risk HPV:
- Usually associated with noncancerous lesions.
- Typical problems caused include skin warts or genital warts (also called genital warts).
- Common low-risk HPV types include 6 and 11.
High-risk HPV:
- There is a strong association with the development of cancer, especially cervical cancer.
- Certain high-risk HPV types are also associated with other cancers, such as vaginal, vulvar, anal, oropharyngeal, and rare penile cancer.
- Examples of high-risk HPV types include models 16, 18, 31, 33, 45, 52, and 58.
Each type of HPV differs according to its DNA sequence, and only some HPV types have a direct link to cancer. The HPV vaccine protects against many high-risk types and some low-risk types of HPV.
How HPV is transmitted
1. Sexual contact: The most common route of transmission is through sexual contact, including vaginal, anal, and oral sex. Even if penetrative sex is not occurring, skin-to-skin contact between any sexual organs can lead to the spread of the virus.
2. Intimate skin-to-skin contact: HPV can be spread when an infected area of skin comes into contact with another piece of skin, not necessarily involving sexual activity.
3. Transmission at birth: Rarely, HPV can be transmitted from an infected mother to a baby and through the reproductive tract during childbirth.
4. Hand transmission: Although uncommon, transmission can theoretically occur through hand contact, such as by touching the skin of an infected genital and then touching one's own or another person's genitals.
5. Infected items or surfaces: Although HPV is not easily transmitted through non-living surfaces, in rare cases, there may be a risk of infection from the use of personal items used by an infected person, such as a towel or razor.
HPV is not usually transmitted through water sources, swimming pools, bed sheets, or toilet seats. In addition, although most HPV infections are associated with sexual transmission, because they can be transmitted through non-sexual contact, HPV is not actually exclusively restricted to sexually active people.
Signs and symptoms of HPV infection
1. Warts on the skin and mucous membranes:
Common warts: usually appear on the fingers, the backs of the hands or feet.
Plantar warts: Appear on the soles of the feet and can sometimes be painful due to pressure.
Flat warts: Smaller, flatter warts that may appear on the face, neck, backs of the hands or legs.
Genital warts: appear on the vulva, penis, perianal area, vagina or cervix. These warts vary in shape and size and can be raised, flat, or cauliflower-like.
2. Carcinogenesis:
Cervical cancer: In women, persistent high-risk HPV infection is the leading cause of cervical cancer.
Other cancers: HPV has also been linked to the development of anal, penile, oropharyngeal, and vulvar and vaginal cancers.
3. Mucosal damage:
Respiratory papilloma: Rarely, HPV may affect the larynx and respiratory tract, causing growth failure and difficulty breathing.
Because most people with HPV infection have no obvious symptoms, they may not know they have the virus and may spread it to others. That's why regular sexual health check-ups are so important for sexually active individuals.
For women, regular cervical cytology smears (PAP tests) can detect abnormal changes in cervical cells, allowing early detection and treatment of problems caused by HPV to avoid the development of cervical cancer. In addition, HPV DNA testing may be recommended for age and risk factors.
If abnormal growths or warts in the genital area appear, you should seek medical attention promptly, as this may be a sign of HPV infection. Other underlying symptoms, such as persistent sore throat or dysphagia, should also be noted and a professional medical evaluation should be sought.
The relationship between high-risk HPV and cancer
1. Cervical Cancer:
Main reason: Almost all cases of cervical cancer are associated with high-risk HPV infection, especially HPV16 and HPV18, which alone account for the majority of cervical cancer cases.
Cellular changes: Long-lasting high-risk HPV infection may lead to precancerous changes in cervical cells, which may eventually evolve into cervical cancer.
2. Other HPV-related cancers:
Anal cancer: strongly associated with HPV infection, especially HPV16.
Penile cancer: High-risk HPV is also associated with penile cancer in men.
Oropharyngeal cancer, particularly tongue and tonsil cancer, is associated with HPV infection, and the incidence of this type of cancer has increased in recent years, partly due to HPV.
Vulvar and vaginal cancer: Although rare, high-risk HPV is also a risk factor for these cancers.
3. Mechanism of carcinogenesis:
Gene interference: When high-risk HPV infects cells, certain genes in the viral DNA (such as E6 and E7) can interfere with the normal gene function of the host cell, such as the tumor suppressor genes p53 and Rb, which can lead to dysregulation of the cell cycle, thereby promoting cancer.
Chronic infection: HPV infection can be long-lasting, and chronic infection exacerbates the effects of the virus on the genetic material of the host cell, increasing the risk of cancer development.
4. Prevention:
Vaccination: Vaccines against HPV are available to prevent infection with many high-risk types of HPV, thereby reducing the risk of related cancers.
Screening: Regular cervical cancer screening (e.g., Pap smear and HPV DNA test) can detect and treat pre-cancerous lesions at an early stage, greatly reducing the incidence of cervical cancer.
Although high-risk HPV is strongly linked to these cancers, it is important to note that not all people with high-risk HPV infection will develop cancer. The body's immune system is usually able to clear the virus, and many infections resolve on their own without causing long-term problems. However, when the infection persists and the body is unable to effectively clear the virus, precancerous lesions and eventual cancer can occur.
HPV precautions
1. Establish safe sex, avoid sexual confusion, maintain a single sexual partner, and reduce the chance of HPV infection.
2. Get vaccinated against HPV. At present, there are two types of HPV vaccines on the market, including bivalent, quadrivalent and nine-valent, which can produce immune protection against different types of HPV virus and reduce the risk of infection.
3. Pay attention to personal hygiene. Keeping the genital organs clean and hygienic, changing underwear frequently, washing underwear separately, and avoiding sharing bath towels, bathtubs and other items with others can effectively prevent HPV infection.
4. Have regular gynecological check-ups. Early detection and treatment of HPV infection can improve the treatment effect and prevent the occurrence of malignant lesions.
5. Boosts immunity. Maintaining a healthy lifestyle, including a balanced diet, moderate exercise, regular work and rest, etc., can help improve the body's immunity and resist the invasion of the virus.
Preventing HPV infection requires the joint efforts of individuals and society to take measures from multiple aspects to reduce the risk of infection. At the same time, people who have been infected with HPV should be actively treated to prevent the occurrence of malignant lesions.
How to screen for HPV in the early stages
1. 宫颈涂片检查（Pap smear测试）：
It is a screening method used to detect cervical precancerous changes and cervical cancer.
It is recommended that women undergo regular Pap testing starting at the age of 21.
During the test, your doctor uses a special tool to collect a sample of cells from the surface of your cervix and send the sample to a lab for microscopic examination.
2. HPV DNA Test:
This is a test that directly detects HPV DNA and can determine if there is a high-risk HPV infection.
HPV DNA testing is generally recommended for women over the age of 30 as women in this age group are at a higher risk of contracting HPV.
Some guidelines recommend that the Pap test and HPV DNA test be done at the same time to improve the accuracy of screening.
3. 共测法（Co-testing）：
In this method, a Pap smear and an HPV DNA test are done at the same time.
Co-testing can provide more complete information and help doctors make more accurate diagnoses.
4. Physical Examination:
Your doctor may also do a physical exam of your cervix to check for any unusual changes or growths.
Screening frequency and age recommendations
Women between the ages of 21 and 29: A Pap smear is recommended every three years.
Women between the ages of 30 and 65: Cervical smear test every three years is optional.
or co-test every five years (Pap smear + HPV DNA test),
Or just an HPV DNA test every five years.
Screening considerations
Sexual intercourse, vaginal medications, or lotions should be avoided prior to screening, as these may affect the accuracy of test results.
If the screening results are abnormal, further evaluation is indicated. Your doctor may recommend more detailed diagnostic procedures, such as a biopsy of the cervix (Pap smear) or a conization of the cervix.
Regular HPV screening is an important measure to prevent cervical cancer, but even women who have been vaccinated against HPV should be screened regularly.
It is best to consult with your local hospital for advice that best suits your individual situation.
What are the misconceptions about HPV?
1. Myth: Only women need to worry about HPV.
Fact: HPV affects people of all genders. While cervical cancer is most closely linked to HPV, the virus can also cause other types of cancer, including penile, anal, and oropharyngeal cancers, which also affect men.
2. Myth: Using a condom can completely prevent HPV infection.
Fact: While condoms can significantly reduce the risk of HPV transmission, they do not provide complete protection because HPV can be transmitted through skin-to-skin contact, which is often not covered by condoms.
3. Myth: HPV is only available to people who have had multiple sexual partners.
Fact: Anyone who is sexually active can get HPV. Even people who have sex with a single partner can get HPV.
4. Myth: HPV always causes obvious health problems, such as genital warts or cancer.
Fact: Most people with HPV infection do not experience any symptoms or health problems. In many cases, the immune system clears the virus within two years without causing any long-term effects.
5. Myth: If the Pap smear results are normal, it means that there is no HPV infection.
Fact: The Pap smear is mainly used to detect abnormal changes in the cells of the cervix, it does not directly detect HPV. A person may still have an HPV infection even if the Pap smear results are normal.
6. Myth: Once you get the HPV vaccine, you don't need to be screened for cervical cancer.
Fact: Although the HPV vaccine protects against many high-risk types of HPV, it does not protect against all HPV infections. Women who have been vaccinated should still have regular cervical cancer screenings as recommended by their healthcare provider.
7. Myth: HPV vaccine is only suitable for teenagers.
Fact: While HPV vaccination is recommended for best results at ages 11 to 12, unvaccinated adults, especially those under the age of 26, can also benefit from the vaccine.
8. Myth: Having HPV means that your partner must be unfaithful to you.
Fact: Because HPV can remain dormant in the body for years without being detected, it is impossible to determine when and from whom HPV was infected.
Understanding these misconceptions can help to better recognize and prevent HPV-related health risks and to take appropriate protective measures.