An STD, or sexually transmitted disease, is a bacterial, viral, or parasitic infection usually transmitted through unprotected vaginal, oral, or anal sex. However, STDs can also spread via non-sexual interactions, such as passing from mother to child during pregnancy, breastfeeding, or childbirth; between drug users who share syringes; or from donor to recipient via infected blood donations. Often referred to as STIs, or sexually transmitted infections, STDs often display few or no symptoms, making diagnosis and treatment unlikely. Although all STDs can be treated, most cannot be cured entirely. As such, health agencies typically encourage prevention, especially through the use of protection when engaging in sexual activity, and regular STD testing.
While the severity of symptoms varies from one STD to the next, some infections can serious indeed—particularly for women. The World Health Organization points out that STDs can lead to neurological disease, cardiovascular disease, infertility, stillbirth, ectopic pregnancies, liver cancer, cervical cancer, and (in the case of the sexually transmitted HIV virus) AIDS. Factors that contribute to rising STD rates include drug use, poverty, and the public stigma associated with STDs and non-monogamous sexual conduct. Conversely, awareness campaigns, the use of condoms, and access to sexual health education are known to decrease the prevalence of STDs.
STD infection rates vary widely by disease and country, but have seen an overall increase in recent years. The World Health Organization estimates that more a million new curable STD infections are created every day. STD rates can be difficult to determine in underdeveloped and developing countries because of the lack of access to health care and dearth of available STD testing—situations which often lead to high STD infection rates as well. By comparison, developed countries tend to have more comprehensive health care systems, so STI testing is much more common and infection rates are much lower. For example, HIV/AIDS infects nearly 27% of people in underdeveloped Eswatini, but only .10% in well-developed Norway.
According to the Centers for Disease Control and Prevention(CDC) and the World Health Organization, the most common type of STD around the world is Human Papillomavirus (HPV), with more than 600 million cases worldwide and 20 million in the United States. Almost every sexually active person catches HPV at some point in life. Some types of HPV have few to no symptoms, while others can lead to genital warts and cervical cancer complications. HPV is preventable for both men and women through vaccination, though there exists no full cure for it once contracted. Additional common STDs around the world include trichomoniasis, chlamydia, gonorrhea, and syphilis—all of which can be cured, though gonorrhea is developing significant resistance to many modern antibiotics.
The United States has some of the highest STD rates in the developed world. The United States had a gonorrhea rate of 123 per 100,000 people in 2015—the highest in the developed world at the time—which increased to 188.4 cases per 100,000 people in 2019. The U.S. also posted the third-highest rate for chlamydia in the developed world with 475 per 100,000 people in 2015, which increased to 552.8 per 100,000 in 2019. STD rates increase in the United States for many reasons, including decreased condom use amongst vulnerable groups such as young people and men who partner sexually with other men. Additionally, state and local programs have experienced budget cuts, resulting in clinic closures, decreased screenings and care, and reduced patient follow-up.
STD rates in the U.S. vary widely from state to state. In 2019, the states with the highest STD rates were Mississippi, Alaska, and Alabama for gonorrhea, Alaska, Mississippi, and Louisiana for Chlamydia, and Nevada, New Mexico, and Mississippi for primary and secondary syphilis. Though not yet available in early 2022, the data for 2020 are expected to show a drop in STI rates across the country compared to 2019—however, health experts expressed concern that this reduction will not reflect a legitimate drop in the number of STIs that exist, but a drop in the number of STI's reported, due to the fact that so many clinics were forced to close during the height of the COVID-19 pandemic.
In Australia, STD cases have risen significantly over the past two decades. Experts attribute the rise to more widespread testing, increasing popularity of online dating, high tourist numbers, and a lack of condom usage, despite people being educated on their effectiveness. Singapore is ranked third overall for the highest STD rates and has the highest rate of syphilis per 100,000 people of 30.39. Singapore’s high rank is perhaps because the government did not initially educate the population about STDs and prevention. It is mandatory to report results for STD tests. This law is not common around the world and is only found in a few countries.
Eswatini, on the southern tip of Africa, has the highest STD rate at 26.%.