When men encounter HPV

This is the 4921st article of Da Yi Xiao Hu

Preface

Human papillomavirus (HPV) is one of the most common sexually transmitted viruses in the world. In recent years, as people's health awareness has gradually increased, HPV vaccines have come into everyone's view and become very popular. In some areas, you even need to draw lots to get the vaccine. At present, HPV vaccines have achieved great success in protecting women's health. So is HPV just a matter for women? HPV viruses are susceptible to infecting squamous epithelial cells of the skin and mucous membranes, and these cells are rarely protected by virus-specific antibodies. Among people with active sexual lives, more than 4/5 of them can be infected with HPV. Young women have the highest risk of HPV infection, and the infection rate among men is relatively low. However, with the changes in romantic sexual orientation and sexual behavior, the HPV infection rate among men is increasing year by year.

1. What is HPV

Human papilloma virus (HPV) HPV is a large group of viruses that includes more than 200 HPV genotypes, of which about 30 to 40 types have affinity for the reproductive tract and regularly or occasionally infect the reproductive tract. HPV is divided into high-risk and low-risk types according to the degree of carcinogenicity. High-risk HPV includes types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 73 and 82; low-risk HPV includes types 2, 3, 6, 7, 10, 11, 13, 32, 40, 42, 43, 44 and 57. However, co-infection with high-risk and low-risk HPV is common.

2. How HPV is transmitted

HPV viruses exist widely and stably in the natural environment, so various types of HPV infections are very common among the population. There are four common ways that HPV is transmitted.

(1) Transmission through sexual intercourse

This is the most common way of transmission. Cross-infection of HPV between couples is common. People who engage in high-risk behaviors such as not taking protective measures, not paying attention to cleanliness before and after sex, and having a chaotic private life are more likely to be infected with HPV.

(2) Indirect contact transmission

Contact with items used by HPV carriers, such as bath towels, washbasins, toothbrushes, underwear, etc. In addition, places such as hotels, swimming pools, and public baths are also gathering places for HPV viruses.

(3) Mother-to-child transmission

If the mother herself has the HPV virus, the fetus will also be at risk of HPV infection during vaginal delivery.

(4) Nosocomial transmission

Infection occurs through contact with utensils used by HPV-infected people in the hospital.

What are the symptoms of HPV?

When women are infected with HPV, they usually develop gynecological diseases such as cervical cancer, vaginal cancer, and vulvar cancer.

HPV infection in men is rarely noticed, but the HPV infection rate in men is very high. Globally, the male genital HPV infection rate is higher than that in women, especially in uncircumcised men, HIV-positive men and homosexual men.

Possible symptoms of HPV infection in men:

(1) Genital warts

Genital warts are a sexually transmitted disease mainly caused by HPV6 and HPV11. The main clinical manifestation is benign hyperplasia of the skin and mucous membranes of the genitals, anus and vulva, which is prone to recurrence and may become cancerous. Genital warts not only affect physiological functions, cause psychological pressure, and bring huge economic burdens to patients, but are also highly contagious.

(2) Male infertility

HPV affects male fertility by infecting sperm. When a man is infected with HPV, sperm motility decreases, sperm morphology changes, and sperm activity decreases, which reduces the quality of his semen. Among them, the change in sperm activity is the most important feature after HPV infection.

(3) Penile cancer

Penile cancer is a rare disease that mainly occurs in middle-aged and elderly men, with a high mortality rate. Penile cancer is mainly squamous cell carcinoma of penis (pSCC). Recent data show that HPV infection can cause about 50.1% of pSCC, of ​​which HPV16 is the most common pathogenic type. The penis is the most susceptible part of men to HPV infection, and the high infection rate of HPV is associated with a lower circumcision rate.

(4) Anal cancer

Anal cancer is a rare malignant tumor with squamous cell carcinoma as the main type. HPV infection is the main factor causing anal cancer, especially the high-risk HPV16. Anal HPV infection varies greatly between different genders and sexual orientations. The infection rate in women is higher than that in men. Anal HPV infection is most common in HIV-positive individuals or men who have sex with men (MSM).

4. If a man has no physical abnormalities, does he not carry HPV?

Just because a man has no physical abnormalities does not mean he does not carry HPV. Some men who are infected with HPV are in an invisible state, with no abnormalities in their vulva or foreskin cavity, and they are unaware that they are infected.

5. Is it necessary for men to get HPV vaccine?

Sexual transmission is a major way of HPV transmission. If either of the sexually active male and female spouses is infected, their spouses have a higher probability of being infected with the corresponding HPV, so vaccine protection for both spouses should be emphasized. At the same time, based on the transmission mode of HPV, HPV-related vaccination for men also has a protective and preventive effect on their male spouses and themselves. Therefore, under the current situation, it is necessary to emphasize the vaccination of men, especially the male spouses of women infected with HPV.

The quadrivalent and nine-valent HPV vaccines have been approved for male injection and have a good immune response in men, which can directly protect men. The current vaccines can cover most HPV-related disease subtypes. The HPV vaccine is 46.9% effective in preventing HPV16-related anal and genital infections in men (continuous contact for >6 months), 88% effective in preventing persistent oral HPV infection, and 61.9% and 46.8% effective in preventing grade 2 and grade 3 anal intraepithelial neoplasia, respectively, indicating that the HPV vaccine can effectively prevent HPV infection and mucosal damage in men. In a study involving 1,767 young people in the United States, the oral and anal HPV infection rates of the quadrivalent vaccine group (22.9%) were lower than those of the unvaccinated group (31.6%), and the effectiveness of vaccine protection decreased with age, which shows the effectiveness of HPV vaccination for men and the necessity of vaccination as early as possible.

The United States, Australia, Scotland, Austria, Canada and many other countries recommend HPV vaccination for men. The effectiveness of HPV vaccination in reducing the burden of HPV-related diseases depends largely on the vaccine coverage in the region. Australia has the highest universal HPV vaccine coverage rate. After nearly a decade of efforts, the female vaccine coverage rate is as high as 80% and the male coverage rate is 76%. The incidence of HPV infection and related diseases in its population has been significantly reduced, and HPV-related diseases are expected to be eliminated in the future. In terms of the current vaccine coverage rates in most countries, the vaccine does not provide enough protection for men. When the vaccine coverage rate for men and women in a region reaches 70%, the herd effect can be optimal and can be protected from instantaneous fluctuations in vaccination rates. However, MSM are less protected from this effect. It is necessary to strengthen the direct protective effect of HPV vaccines on men to reduce HPV infections in men and even the entire population.

6. How to prevent HPV infection in men

(1) Circumcision

First, HPV likes to grow in a warm and humid environment. After circumcision, the male genitals are more hygienic and dry, which greatly reduces the probability of HPV infection. Secondly, when the foreskin covers the glans, the tender skin on the inside of the glans is called the inner plate, and the skin exposed on the penis is called the outer plate. After friction during sex, the inner plate skin is prone to slight cracks and damage. Once damaged, the virus can "have a crack to get in." Therefore, circumcision is very important for men to prevent HPV.

(2) Maintain vaginal hygiene

(3) Be chaste and avoid having too many sexual partners. Use safe sexual intercourse methods and take protective measures.

References:

[1] Teng Qiuli, Niu Maoyuan, Liu Yuying, Ren Shurong. The harm of HPV infection to men and the protection of HPV vaccination to men[J]. Chinese Journal of Immunology, 2022, (Issue 4).

[2] Can men also be infected with HPV? [J]. Health and Wellness, 2020, (Issue 1).

[3] Si Keyi. HPV vaccination can also prevent cancer in men[J]. Rehabilitation, 2022, (Issue 2).

Author: Shanghai University of Traditional Chinese Medicine, School of Rehabilitation Medicine

Gu Yiwen 2022441009