英文描述HPV危害、传播、预防，引用专业文献数据

Human Papillomavirus (HPV) is a group of more than 100 related viruses, many of which are sexually transmitted and some can cause cancer. Here's an overview:

1. Harm: HPV infections can lead to various health problems including genital warts and several types of cancer. In fact, according to the Centers for Disease Control and Prevention (CDC), HPV causes nearly all cases of cervical cancer, along with cancers of the anus, mouth and throat, penis, and vagina [1]. A significant percentage of these cancers could be prevented if HPV-related diseases were eliminated.

2. Transmission: HPV is mostly spread through sexual contact, even if the infected person is not showing symptoms. Skin-to-skin contact with an infected person's genitals, mouth, or anus can transmit the virus [2]. Use of condoms and dental dams can reduce the risk but may not fully protect against transmission because HPV can infect areas not covered by a condom or dam.

3. Prevention: The most effective way to prevent HPV-related diseases is vaccination. The CDC recommends HPV vaccination for all 11- and 12-year-old children, girls and boys. Vaccination at this age promotes a stronger immune response and helps prevent infection before it occurs.接种疫苗也可以为已成年但未受到HPV感染的年轻人提供保护。 Regular screening tests, like Pap tests for women and anal cytology tests for certain individuals, can help detect precancerous changes and prevent cancer from developing [3].

4. Data and References:

• "Nearly all cervical cancers are caused by HPV." (CDC) [1].
• "Genital HPV infection is so common that at least 50% of sexually-active men and women will get HPV in their lifetime." (CDC) [2].
• "Screening is crucial for the early detection and treatment of precancerous lesions and has led to a reduction in the incidence of cervical cancer in countries where it is widely implemented." (WHO) [3].

References: [1] Centers for Disease Control and Prevention. "Genital HPV Infection - Fact Sheet." March 25, 2020. [2] Centers for Disease Control and Prevention. "HPV and Men - Fact Sheet." March 25, 2020. [3] World Health Organization. "Human papillomavirus (HPV) and cervical cancer." November 2020.