Hello, everyone. Today we're going to turn our attention to human papilloma virus and begin with its epidemiology. HPV is the most common sexually transmitted infection. Almost all females and males will be infected with at least one type of HPV at some point in their lives. Most people never know that they've been infected unless a woman has an abnormal pap smear with a positive HPV test. Most infections, as you can see on this slide, happen during the teen and college age years. HPV is transmitted through skin to skin contact through vaginal, anal, or oral intercourse. HPV exposure can occur at any type of intimate sexual contact. Intercourse is not necessary to become infected. Nearly 50 percent of high school students have already engaged in sexual, which is vaginal-penile intercourse, as shown here. For example, a third of ninth graders and two-thirds of twelfth graders have engaged in sexual intercourse, and 24 percent of high school seniors have had sexual intercourse with four or more partners. This line graph shows how quickly HPV infection occurs after first intercourse. Genital HPV infection occurs frequently in women within one year of their first male sex partner. Some women acquired a genital HPV infection prior to having vaginal intercourse, suggesting that they may have had non-penetrative sexual contact. Young women are at a high risk of acquiring HPV infection from her first male sex partner and the risk is increased by the partner's prior sexual experience. Even if a teen isn't having sex, they may be engaging in behaviors that can expose them to HPV, even girls who report never having sexual intercourse, still had, in this study, HPV infection. This slide demonstrates a study that examined the frequency of vaginal HPV and the association with noncoital sexual behavior in longitudinally followed cohort of adolescent women without prior vaginal intercourse. HPV was detected in 46 percent of women prior to first vaginal sex, 70 percent of these women reported noncoital behaviors that may in part explain genital transmission. Cervical cancer was once the leading cause of cancer death for women in the United States, now it is the most preventable of all of the female cancers. The pap test has helped decrease the number of women in the United States with cervical cancer by about 75 percent in the past 50 years. However, even with an excellent cervical cancer screening program in the US, there are still around 12,000 cases of cervical cancer each year in this country. Many people think of gynecologic cancers as just affecting older women, but cervical cancer affects one in six women who are in the prime of their reproductive years. You can see this data illustrated in the slide, almost 26 percent of cervical cancer occur in women who are between the ages of 35 and 44, with 14 percent between ages 20 and 34, and almost 24 percent between 45 and 54. Most oropharyngeal cancers that were previously thought to be caused by tobacco and/or alcohol use are now being identified as HPV-related cancers. The number of oropharyngeal cancers diagnosed that are not caused by HPV has declined by half. The prevalence of HPV oropharyngeal cancers has increased from 16 percent in 1984-'89 period to almost 72 percent in the period from 2000-2004. Population-level incidence of HPV-positive cancers increased by 225 percent, while HPV-negative cancers declined by 50 percent. So if the trends continue, if the annual number of HPV positive oropharyngeal cancers is expected to surpass the annual number of cervical cancers by the year 2020, we don't have these data yet, so stay tuned. Now, here are two graphs from the CDC illustrating anogenital warts and the prevalence per 100,000 person-years. So the prevalence of anogenital warts was examined using health care claims of privately insured females and males in the ages of 15 to 39 years and this shows the period of 2006-2014. The prevalence among adolescent females ages 15 to 19 years declined, but it was non-significantly during the 2006, 2008 period and then significantly decreased through 2014. Focusing on women ages 20 to 24, genital wart prevalence was stable in the 2006-'09 period, but declined significantly during 2009-'14. Prevalence among women 25 to 29 years also decreased significantly in the 2009-'14 time period. Prevalence increased or was stable during the entire period for women ages 30 to 39. Thought focusing on the males, which is in the lower part of the slide, anogenital warts prevalence increased significantly during 2006, '09 for all age groups except those ages 15 to 19, and you can look at the various breakdown if you're interested. Now, the annual prevalence of high-grade histologically detected cervical intraepithelial neoplasia or cancers, grade 2 and 3, during 2007-'14 was estimated using health care claims from 9 million females, ages 15 to 39, who received cervical cancer screening in a given calendar year, and this is reflected in the CDC data shown here. The prevalence of CIN 2 or greater decreased significantly in women 15 to 19 and 20 to 24 years of age. Among the 15 to 19 year olds, annual percent change in CIN 2 or greater was almost 20 percent less during the 2007-'09 period and 12 percent less during the 2009-'14 period. If you look at women from 20 to 24 years of age, the annual percent change decreased almost seven percent during the 2007-'12 period and then almost 13 percent during the 2012-2014 period, and there was no decreases in CIN 2 or greater observed in women age 25 to 39 years. So here we see the cost of HPV-associated disease in the United States, taking into account the burden of the cancers and other HPV-associated diseases. The total cost of HPV associated diseases is $8 billion, including the 6.6 billion due to routine screening. With new technologies, it's hoped that there can be more efficient screening augmented by more organized screening systems, and of course, vaccination leading to reduction of the screening costs. Estimates of the direct medical costs attributable to human papilloma virus can help to quantify the economic burden of HPV and to illustrate the economic benefits of the HPV vaccine. Treatment of cervical pre-cancer and cancer can lead to many complications in women, particularly of childbearing age. For example, cervical cancer is often treated by hysterectomy, leaving many young woman unable to have any or additional children. High-grade or severe pre-cancerous lesions often require treatment that can cause cervical incompetence or cervical stenosis, and cervical incompetence can lead to preterm delivery and cervical stenosis can lead to birth complications. Both of these lead to a tremendous burden on the mother, the infant, and the family.
