The challenge of “new STDs” involves rapidly changing sexual health threats, not just novel pathogens. This evolving landscape includes infections expanding their geographic reach, becoming harder to treat, or utilizing sexual contact as a newly recognized route of transmission. Global interconnectedness and shifting public health priorities allow established infections to resurge quickly. Understanding these emerging threats requires focusing on infections that are changing their behavior and presenting new difficulties for prevention and treatment.
Defining Emerging Sexually Transmitted Infections
The term “emerging” STIs refers to three distinct scenarios challenging public health systems. The first involves re-emerging infections, which are known diseases that were previously controlled but are now returning at higher rates or in new populations. Syphilis resurgence is a prime example, showing a profound increase in incidence across multiple regions.
The second scenario is the acquisition of new characteristics by existing pathogens, particularly antimicrobial resistance (AMR). Infections like Gonorrhea and Mycoplasma genitalium are not new, but their ability to evade common treatments has fundamentally changed their threat level. The third category includes pathogens not traditionally classified as STIs, but which have demonstrated the capacity for sexual transmission during outbreaks, such as Mpox and Zika. Their sexual spread demands new surveillance and containment strategies.
Current High-Priority Emerging STI Threats
Highly Resistant Gonorrhea
The rise of highly drug-resistant Neisseria gonorrhoeae, often termed “super gonorrhea,” is an immediate emerging threat. This bacterium develops resistance to nearly every class of antibiotic used to treat it, including cephalosporins, which were once the last line of defense. The World Health Organization (WHO) notes an increasing number of countries reporting multi-resistant N. gonorrhoeae strains.
This resistance could lead to untreatable cases and long-term complications, such as pelvic inflammatory disease, infertility, and increased risk of HIV transmission. Surveillance programs track treatment failures at different anatomical sites, as resistance varies depending on whether the infection is in the throat, genitals, or rectum. The pathogen’s adaptability pressures researchers to find new therapeutic options quickly.
Syphilis Resurgence
Syphilis, caused by the bacterium Treponema pallidum, is a re-emerging threat with global infection rates surging in recent years. The increase in adult syphilis cases has caused a rise in congenital syphilis, where the infection is passed from a pregnant person to their fetus. Congenital syphilis can lead to severe adverse birth outcomes, including stillbirth, infant death, and long-term health complications for the child.
In 2022, new adult syphilis cases reached an estimated eight million worldwide, undermining public health goals. The rise is pronounced in regions where access to timely diagnosis and treatment, typically a single dose of penicillin, has been disrupted. This sustained increase demonstrates a failure in public health infrastructure to contain a treatable infection.
Mycoplasma genitalium (Mgen) and Mpox
Mycoplasma genitalium (Mgen) is a bacterium associated with urethritis and cervicitis that is becoming increasingly resistant to first-line antibiotics like azithromycin. This drug resistance makes treating Mgen challenging and contributes to its recognition as a growing public health concern. Because Mgen is difficult to isolate and study, its spread and resistance patterns are harder to track than more common STIs.
The recent global outbreak of Mpox (formerly monkeypox) highlighted the potential for non-classical diseases to spread rapidly through sexual networks. Although Mpox is not exclusively an STI, the 2022 outbreak demonstrated that close physical contact during sexual activity was the predominant mode of transmission, particularly among men who have sex with men. This forced public health officials to adapt surveillance and intervention strategies for a disease not previously considered a primary sexual health concern.
Factors Driving the Rise of Emerging STIs
The emergence and re-emergence of these infections are driven by a complex interplay of biological, social, and systemic factors. The most significant biological driver is the acceleration of antimicrobial resistance (AMR), particularly in bacterial infections like Gonorrhea and Mgen. The widespread use and misuse of antibiotics, both within and outside of healthcare settings, selects for bacteria that survive treatment, limiting effective therapeutic options.
A systemic factor is the decline in public health infrastructure and funding, exacerbated by the COVID-19 pandemic. Resource allocation was diverted from sexual health clinics and STI surveillance programs, reducing testing, contact tracing, and treatment capacity. This disruption created a backlog of undiagnosed cases, allowing infections to spread silently.
Changes in social behavior and global mobility complicate containment. Increased international travel and expanding sexual networks can rapidly disseminate new or resistant strains across geographic boundaries. Furthermore, decreased condom use in some populations, sometimes linked to the availability of HIV pre-exposure prophylaxis (PrEP), has removed a physical barrier to STI transmission.
Public Health Response and Prevention Strategies
The public health response focuses on enhanced surveillance, innovative prevention tools, and accelerated research. Surveillance systems are being strengthened globally to track drug-resistant strains, such as the WHO Gonococcal Antimicrobial Surveillance Programme, which monitors antibiotic effectiveness against N. gonorrhoeae. Improved data collection is essential for quickly identifying outbreaks and guiding localized intervention strategies.
Prevention efforts include innovative pharmaceutical interventions like Doxycycline post-exposure prophylaxis (DoxyPEP). DoxyPEP is being explored to reduce the risk of acquiring bacterial STIs like Syphilis and Chlamydia in high-risk populations. This strategy involves taking an antibiotic after sexual activity to prevent infection, requiring careful monitoring to prevent new resistance development.
Long-term solutions involve investment in research and development for new vaccines and therapeutic agents. Efforts are underway to develop vaccines against pathogens like Gonorrhea, Syphilis, and Chlamydia. For individuals, consistent screening remains important, especially given increasing asymptomatic infections and the prevalence of drug-resistant strains that require precise, early diagnosis.