STDs: What Are They and How Do You [not] Get Them?By Everyday Health. Listen to the ► Podcast at How To Sex.   This episode deals with the following STD concerns: Chlamydia,  Genital Herpes, Gonorrhea, Hepatitis B, HIV, HPV, Molluscum Contagiosum, Syphilis, Trichomoniasis, Chlamydia, Genital Herpes, Gonorrhea, Hepatitis B, HIV, HPV, Molluscum Contagiosum, Syphilis, Trichomoniasis.The number of cases of sexually transmitted diseases (STDs), now more commonly referred to as sexually transmitted infections (STI), in the United States hit an all-time high in 2019, according to data released on April 13, 2021, by the Centers for Disease Control and Prevention (CDC). The CDC’s surveillance report shows that nearly 2.5 million new cases of gonorrhea, syphilis, and chlamydia were reported that year. Chlamydia remained the most common condition reported to the CDC, with close to 1.8 million cases, up 19 percent since 2015. Gonorrhea diagnoses reached 616,392, up 56 percent since 2015. And primary and secondary syphilis diagnoses reached 129,813, up 74 percent since 2015.Of high concern is that congenital syphilis cases, that is, syphilis in newborns, nearly quadrupled between 2015 and 2019, reaching 1,870 cases. From 2018 to 2019 the number of stillbirths caused by syphilis increased from 79 to 94, and the number of congenital syphilis-related infant deaths rose from 15 to 34 deaths.While the 2019 STD statistics reflect pre-COVID-19 pandemic numbers, preliminary data from 2020 suggests many of the same trends continued during the pandemic. Experts attribute some of the growth in STDs in 2020 to disruptions in STD testing and treatment programs caused by the pandemic.While 2.5 million cases of chlamydia, gonorrhea, and syphilis may sound like a lot, it’s likely an undercount: Many people with these and other STDs, formerly known as venereal diseases, go undiagnosed and untreated. The CDC estimates that nearly 20 million new sexually transmitted infections occur every year, accounting for almost $16 billion in healthcare costs annually.Inequities in STD BurdensThe numbers of STDs increased in all age groups and among all racial and ethnic groups in 2019, according to CDC statistics. However, some groups saw higher rates of STDs than others:People ages 15 to 24 accounted for 61 percent of chlamydia cases and 42 percent of gonorrhea cases.Gay and bisexual men accounted for nearly half of all primary and secondary syphilis cases.Here’s what you need to know about how to spot, treat, and prevent STDs.What Is the Definition of an STD?“STDs are diseases that are passed from one person to another through sexual contact,” a representative of the CDC says.According to the CDC, some of the common STDs are chlamydia, gonorrhea, herpes simplex virus type 2 (HSV-2), human immunodeficiency virus (HIV), human papillomavirus (HPV), and syphilis. "Many of these STDs do not show symptoms for a long time," per the CDC, "but they can still be harmful and passed on during sex.”Virtually all STDs can be transmitted through anal, vaginal, or oral sex. In addition, some STDs can also be transmitted through close skin-to-skin contact, even if no intercourse occurs.HPV, for example, can be spread through skin-to-skin touching. In addition, “Molluscum contagiosum, a viral skin disease, can be spread through sexual or casual contact, as can scabies, an itchy skin condition caused by a mite infestation. It is also possible to get scabies from an infected sleeping bag or bed,” says Edward W. Hook III, MD, an endowed professor of infectious disease translational research in the departments of medicine, epidemiology, and microbiology at the University of Alabama in Birmingham, who works with the CDC.STDs don’t just affect the genital regions: “Oral herpes can be transmitted through oral and genital sex,” says Dr. Hook.It is important to remember that STDs may have no symptoms. However, new vaginal