STD Statistics in the United States: 2024 CDC Data

The United States reports approximately 20 million new sexually transmitted infections every year — roughly one new infection every 1.6 seconds. Despite decades of public health investment, several STIs are now more prevalent than at any point in recent memory: primary and secondary syphilis reached its highest case count since 1950 in 2023, congenital syphilis has surged 755% since 2012, and gonorrhea carries a resistance profile that prompted the CDC to classify it as an urgent-threat antimicrobial-resistance pathogen. Understanding these numbers — where they come from, who they affect, and how they are changing — is the foundation of any serious STI prevention or policy effort.

The scale matters in part because most STIs are asymptomatic. An estimated 70% of chlamydia infections in women produce no symptoms at all, and roughly 50% of gonorrhea infections in men go unnoticed. That invisibility is what enables silent transmission across social networks and explains why surveillance data — not symptom counts — is the only reliable way to track the epidemic. The CDC's National Notifiable Diseases Surveillance System (NNDSS) requires that clinicians and laboratories report confirmed cases of chlamydia, gonorrhea, syphilis, and several other STIs to local and state health departments, which then report aggregated data to the CDC. The resulting annual Sexually Transmitted Infections Surveillance Report is the authoritative source used throughout this article.

These surveillance figures nonetheless undercount true prevalence. Only infections that are tested and reported enter the case count; untested asymptomatic infections are invisible to the system. The American Sexual Health Association estimates that if all STIs — including undiagnosed ones — were counted, the true annual burden would approach 26 million new infections. The CDC's 20 million figure, derived from the Kreisel et al. (2021) prevalence methodology, represents the most widely cited and methodologically rigorous estimate available. Both figures underscore the same conclusion: routine screening, not symptom-driven testing, is the primary public-health tool for controlling STI transmission in the United States.

Chlamydia — the most reported bacterial infection in the United States

Chlamydia trachomatis caused 1,648,568 reported cases in 2023, a rate of 492.2 per 100,000 population, making it the most reported bacterial STI in the United States for the 30th consecutive year. Despite a modest 2.2% decline from the 2022 figure of 1,649,716 cases, chlamydia rates remain more than twice their 2000 levels, reflecting both improved diagnostic testing and persistent transmission. The NAAT (nucleic acid amplification test) has dramatically increased sensitivity since its widespread adoption in the mid-2000s, so some of the apparent increase from 2000 onward reflects better detection rather than a pure increase in infections.

The age distribution is strikingly concentrated: 55.8% of all reported chlamydia cases occur in people aged 15–24. Among women aged 15–19, the rate was approximately 2,700 per 100,000 in 2023 — more than five times the overall national rate. The disproportionate burden in young women is partly biological: cervical ectopy (the presence of columnar epithelial cells on the outer cervix, which is common and normal in adolescents and young adults) makes the cervix more susceptible to chlamydial infection. This is the mechanistic basis for the USPSTF's Grade B recommendation that all sexually active women aged 24 and younger receive annual chlamydia and gonorrhea screening regardless of symptoms or self-reported risk.

Left untreated, chlamydia ascends from the cervix to the upper reproductive tract in approximately 10–15% of untreated women, causing pelvic inflammatory disease (PID), which in turn is the leading infectious cause of tubal-factor infertility and ectopic pregnancy in the United States. In men, untreated chlamydia can cause epididymitis. These downstream complications cost the US healthcare system an estimated $691 million annually (ASHA 2021), making routine screening cost-effective even when accounting for the cost of the test itself.

Racial and ethnic disparities in chlamydia rates are large, persistent, and structurally driven. In 2023, the chlamydia rate among Black Americans was 5.3 times higher than the rate among white Americans (CDC STI Surveillance 2023). The rate among American Indian/Alaska Native populations was 3.3 times higher than among white Americans. These differences are not explained by differences in sexual behavior; research consistently shows that they are driven by structural factors including differential access to healthcare and screening, residential segregation concentrating transmission networks, higher rates of poverty limiting healthcare-seeking, and historic policy failures in STI public health resources in disproportionately affected communities. The CDC's STI National Strategic Plan 2021–2025 explicitly identifies health equity as a foundational goal.

Gonorrhea — rising antibiotic resistance makes this the urgent priority

Neisseria gonorrhoeae caused 601,240 reported cases in 2023, a rate of 179.5 per 100,000 — a 28% increase from 2019 and more than 2.5 times the rate in 2009. The clinical trajectory of gonorrhea is unique among common STIs because of its unmatched capacity to acquire antibiotic resistance. Gonorrhea has developed resistance to sulfonamides, penicillin, tetracyclines, fluoroquinolones, and to earlier-generation cephalosporins in sequence — each time, the CDC updated treatment guidelines and the pathogen adapted. In 2012, the CDC designated gonorrhea an urgent-threat antimicrobial-resistance pathogen, the highest-priority tier in its AMR Threat Report. Dual therapy — currently ceftriaxone 500mg intramuscular injection as monotherapy (raised from 250mg in 2020 to slow resistance) — is now standard because the previous combination therapy is no longer reliably effective. In December 2025, the FDA approved two new oral antibiotics (zoliflodacin and gepotidacin) — the first new drug classes for gonorrhea in over 30 years.

Gonorrhea is frequently asymptomatic, particularly in the pharynx and rectum, where infection can persist for weeks or months without symptoms while still transmitting. Men who have sex with men (MSM) account for approximately 47% of all male gonorrhea cases despite representing a small fraction of the male population, reflecting both higher sexual network density and more comprehensive screening in communities with access to MSM-focused sexual health services. Women bear significant gonorrhea burden as well: untreated cervical gonorrhea ascends to cause PID with similar rates and consequences as chlamydia.

Syphilis — the most alarming trend in modern STI surveillance

Primary and secondary (P&S) syphilis, the infectious stages of Treponema pallidum infection, reached 209,253 cases in 2023 at a rate of 15.8 per 100,000 — the highest case count since 1950 and an increase of more than 1,000% since the post-2000 nadir when the US had fewer than 6,000 annual P&S cases and public health officials briefly discussed elimination. All-stage syphilis (including primary, secondary, early latent, late latent, and tertiary) totaled more than 207,000 primary and secondary cases alone, with additional latent stages adding substantially to the total case burden. The acceleration has been consistent: P&S cases increased 5.1% from 2022 to 2023 even as chlamydia modestly declined.

Congenital syphilis is a public health emergency. When syphilis passes from a pregnant person to a fetus, it can cause stillbirth, premature birth, and severe multi-organ damage in newborns. In 2023, there were 3,882 reported congenital syphilis cases — a 755% increase since 2012. The US congenital syphilis rate in 2023 was 10.3 per 100,000 live births. This is not primarily an access problem in the aggregate: more than 60% of congenital syphilis cases in recent years occurred in pregnancies that had prenatal care, suggesting late presentation for care, insufficient retesting in the third trimester, or failures in the clinical-to-treatment pipeline. Most congenital syphilis cases are entirely preventable with timely diagnosis and treatment of pregnant people. See the congenital syphilis crisis breakdown for the full state-level data and prevention gaps.

The epidemiology of syphilis has shifted markedly over the past decade. Through the mid-2010s, P&S syphilis was concentrated among men who have sex with men. Since 2017, the epidemic has expanded into heterosexual networks and into women of reproductive age at an accelerating rate. The share of P&S cases in women roughly doubled between 2017 and 2023. This demographic shift — from a concentrated epidemic in a high-screening subpopulation to a more generalized epidemic — is the proximate driver of the congenital syphilis surge, because women of reproductive age who acquire syphilis represent a new risk for perinatal transmission.

HIV — the long-term epidemic

HIV is the most consequential STI in US history and, in many ways, remains its most pressing long-term sexual health challenge. In 2022, there were approximately 39,000 new HIV diagnoses in the United States — a significant improvement from peak transmission of more than 130,000 new infections per year in the late 1980s, but still far from the Ending the HIV Epidemic initiative's target of reducing new transmissions to fewer than 3,000 per year by 2030. The 1.2 million people currently living with HIV in the US include an estimated 13% — roughly 157,000 people — who are unaware of their infection, representing the primary reservoir for ongoing transmission.

The introduction of pre-exposure prophylaxis (PrEP) in 2012 has been transformative for high-risk individuals. As of 2022, an estimated 360,000 people were taking PrEP in the US, but the CDC estimates that more than 1.2 million people could benefit from it — a coverage gap that disproportionately affects Black and Hispanic communities. Among people living with HIV who are diagnosed and on antiretroviral therapy (ART), viral suppression to undetectable levels means they cannot transmit HIV sexually — the U=U (Undetectable = Untransmittable) framework is now well-established. The cascade-of-care statistics are therefore the critical metric: not just how many people have HIV, but how many are diagnosed, linked to care, retained in care, on ART, and virally suppressed. See HIV viral suppression rates by state for the 50-state breakdown.

HIV disproportionately affects Black and Hispanic Americans, gay and bisexual men, and people who inject drugs. Black Americans account for approximately 42% of new HIV diagnoses while representing 13% of the US population. Gay and bisexual men account for roughly 67% of new male HIV diagnoses. These disparities are not narrowing at the rate required to meet Ending the HIV Epidemic targets, in part because PrEP uptake, testing access, and linkage to care remain inequitably distributed across race, geography, and income.

HPV — the most common STI overall

Human papillomavirus (HPV) is the most prevalent STI in the United States by a wide margin, but it is deliberately excluded from CDC case-count surveillance because it is so ubiquitous that surveillance of individual cases would not be informative for public health action. Instead, the CDC tracks HPV-attributable disease burden. The current estimates: approximately 43 million active HPV infections exist in the US at any given time, with approximately 14 million new infections occurring each year. An estimated 80% of sexually active Americans will acquire at least one HPV strain in their lifetime. The vast majority of HPV infections are cleared by the immune system within two years without medical intervention and without symptoms.

The public health urgency with HPV is concentrated in two domains. First, oncogenic HPV strains (primarily HPV-16 and HPV-18) cause approximately 36,000 HPV-attributable cancers per year in the United States — including cervical, oropharyngeal, anal, vulvar, vaginal, and penile cancers. Cervical cancer was once the leading cause of cancer death among US women; the combination of Pap smear screening and HPV testing has reduced cervical cancer incidence by more than 70% since 1975. Second, non-oncogenic strains (primarily HPV-6 and HPV-11) cause genital warts, affecting approximately 360,000 people annually. The Gardasil 9 vaccine, recommended for all people through age 26 (and through age 45 for some adults), protects against the nine HPV strains responsible for approximately 90% of cervical cancers and genital warts.

HPV vaccination coverage in the US has been increasing but remains below optimal levels. Among adolescents aged 13–17, approximately 62% have received the complete HPV vaccine series as of 2022, leaving a substantial proportion of the population unprotected. The lag between vaccination and visible cancer reduction is measured in decades — the full impact of current vaccination programs will not be seen in cancer incidence data until the 2040s. The current cancer burden from HPV reflects vaccination rates and screening patterns from 10–20 years ago.

Demographic patterns — who is most affected?

Age is the strongest demographic predictor of STI risk. People aged 15–24 account for approximately half of all new STI cases in the United States each year, despite representing roughly 25% of the sexually active population. This age concentration reflects multiple factors: higher rates of partner change, lower rates of consistent condom use, lower screening uptake outside of formal medical systems, and the biological reality that the cervical ectopy common in adolescent and young adult women increases susceptibility to chlamydia and gonorrhea. The USPSTF's recommendation for annual chlamydia and gonorrhea screening for all sexually active women aged 24 and younger is directly calibrated to this age-specific burden.

Gender patterns differ significantly by infection. Women bear a disproportionate burden of chlamydia and gonorrhea complications relative to reported case rates, because asymptomatic infections in women are more likely to ascend to the upper reproductive tract and cause PID, infertility, and ectopic pregnancy. For syphilis, men account for the majority of reported P&S cases — in 2023, the male-to-female ratio for P&S syphilis was approximately 4:1, reflecting the concentration of syphilis in MSM networks. However, the female rate is increasing faster than the male rate, and the gender ratio is narrowing. For HIV, women account for 19% of new diagnoses, with Black women accounting for 52% of all new HIV diagnoses in women.

Racial and ethnic disparities are the most persistent and troubling pattern in US STI surveillance. These disparities exist for every reportable STI and are particularly pronounced for bacterial infections. The CDC's 2023 surveillance data show: Black Americans have a chlamydia rate 5.3 times higher than white Americans; a gonorrhea rate 7.0 times higher than white Americans; and a P&S syphilis rate 3.8 times higher than white Americans. American Indian/Alaska Native populations show rates 3–4 times higher than white Americans for most infections. The CDC explicitly attributes these disparities to structural determinants — residential segregation, differential access to healthcare, economic inequality — rather than differences in sexual behavior between populations.

Geography creates its own STI risk patterns. STI rates are systematically higher in the South and Southeast United States than in the Northeast or Midwest. States in the Deep South — Mississippi, Louisiana, Alabama, Georgia — consistently rank among the highest for chlamydia, gonorrhea, and syphilis rates. Rural areas face compounding barriers: fewer testing venues, greater distances to care, higher rates of uninsurance, and greater social stigma around STI testing. Urban areas generally have both higher absolute rates (due to network density) and better testing infrastructure, which partly explains why the measured gap between urban and rural rates understates the true testing disparity.

State-by-state comparison

STI rates vary by a factor of 3–4 between the highest- and lowest-burden states in the United States. This geographic variation reflects differences in population demographics, healthcare access and coverage rates, historical investment in sexual health infrastructure, rates of testing and reporting, and the underlying structure of sexual networks. The data below illustrates the spread across states; for the full 50-state rankings see STD rates by state, syphilis rates by state, and HIV viral suppression by state.

Mississippi's chlamydia rate is approximately 3.6 times New Hampshire's; its gonorrhea rate is 6.6 times higher. These are not marginal differences — they represent fundamentally different epidemic intensities that require different levels of clinical and public health resources. State-level data can obscure within-state county-level variation that is often even more extreme. For local testing resources and county-level statistics, see our STD testing location finder.

Trends — what the data shows from 2020 to 2023

The COVID-19 pandemic created a significant disruption in STI surveillance in 2020. Reported chlamydia cases fell from 1,808,703 in 2019 to 1,579,885 in 2020 — a 12.6% decline that public health officials immediately recognized as primarily a testing artifact rather than a true reduction in transmission. As sexual health clinics closed or shifted to telehealth, testing rates plummeted, asymptomatic infections went undetected, and the case-reporting pipeline was disrupted. The same artifact appeared in gonorrhea (down 8.8% in 2020) and even in syphilis to a lesser degree. The subsequent rebound in 2021 and 2022 represented a combination of returning testing infrastructure and the downstream effect of uncounted and untreated infections from 2020 continuing to transmit.

For chlamydia, the post-2020 trend is one of recovery and stabilization rather than surge: cases rebounded to 1.65 million in 2021 and have remained in that range through 2023. The slight 2022-to-2023 decline of 2.2% is a positive signal but should be interpreted cautiously — it remains within the range of year-to-year surveillance variation, and chlamydia rates are still dramatically above their 2000 levels. For gonorrhea, the trend is more concerning: cases have risen each year since 2009, with only a modest COVID-related interruption in 2020, and 2023 rates are at their highest since 1993. The surge in gonorrhea is occurring simultaneously with rising antimicrobial resistance, which means each new case carries higher treatment risk than a case in prior decades.

Syphilis is the most alarming trend line in modern US STI surveillance. P&S syphilis cases increased from 74,702 in 2020 to 116,980 in 2021, 176,713 in 2022, and 209,253 in 2023 — a 47% increase in just the final two years. This is not a COVID rebound; the acceleration in syphilis predates 2020, and the increase from 2022 to 2023 alone (18.4%) is larger than the total case count was in 2001. Congenital syphilis has mirrored this trajectory, rising from 2,855 cases in 2021 to 3,882 in 2023. The trend shows no sign of inflecting, and absent a substantial increase in screening of pregnant people and their partners, public health models project continued increases through at least 2026.

Why most STIs go undiagnosed

The gap between true STI prevalence and reported case counts is large and well-documented. The Kreisel et al. (2021) study estimated that fewer than half of the estimated 26 million new STIs per year in the US enter the surveillance system. This gap has clinical, behavioral, and structural causes that operate simultaneously — and understanding them is necessary for closing the testing gap that underlies the entire epidemic.

The most fundamental cause is asymptomatic infection. The CDC estimates that approximately 70% of chlamydia infections in women produce no symptoms whatsoever. In men, approximately 50% of chlamydia infections and a substantial fraction of urethral gonorrhea infections are asymptomatic. Pharyngeal and rectal gonorrhea infections are almost universally asymptomatic. Syphilis in its primary stage produces a single painless genital ulcer (chancre) that can go unnoticed, heals on its own within three to six weeks, and is followed by an asymptomatic latent period during which the infection is still transmissible. This biology makes symptom-driven testing — waiting until something hurts or looks abnormal — a fundamentally inadequate detection strategy.

Beyond the biology, a series of structural and behavioral barriers suppress testing rates even for people who know they should be tested. The CDC estimates that fewer than one in five sexually active adults was tested for STIs in the past year. Cost and insurance concerns play a significant role: STI testing can cost $100–$300 out of pocket without insurance, and many insured people avoid using coverage because an explanation of benefits document mailed to their household will reveal the test to family members. Fear of positive results and the social stigma associated with STI diagnoses also function as active barriers — research consistently shows that perceived stigma, not cost, is the single largest reported barrier to STI testing in surveys of sexually active adults.

The cost of untreated STIs in the United States

Untreated STIs impose costs that go far beyond the infection itself — costs measured in permanent health consequences, complicated pregnancies, transmitted infections, and dollars. The American Sexual Health Association (ASHA) estimates the total direct healthcare cost of STIs in the United States at approximately $16 billion per year — a figure that captures only the direct medical expenditure and excludes indirect costs like lost productivity and the long-term burden of HIV.

Infertility is the most common non-HIV long-term consequence of bacterial STIs. Untreated chlamydia ascends to cause pelvic inflammatory disease in an estimated 10–15% of untreated women; PID causes tubal scarring that results in infertility in approximately 20% of cases and ectopic pregnancy — a life-threatening medical emergency — in 9% of cases. The CDC estimates that 20,000 US women become infertile each year as a direct result of undetected, untreated chlamydia or gonorrhea.

Congenital syphilis carries severe and largely preventable health consequences including stillbirth (occurring in approximately 40% of pregnancies with untreated maternal syphilis), premature birth, low birth weight, neonatal neurological damage, bone and organ abnormalities, and death. The average direct treatment cost for a single case of congenital syphilis — including the extended hospitalization typically required — exceeds $16,000. At 3,882 cases in 2023, the minimum healthcare cost of congenital syphilis alone approached $62 million annually, not counting lifetime disability costs.

STIs dramatically increase HIV transmission risk. Genital ulcer diseases (herpes, syphilis, chancroid) disrupt the mucosal barrier and increase both HIV acquisition and transmission risk by an estimated 2–5 times. Gonorrhea and chlamydia cause local inflammatory responses that concentrate HIV-susceptible CD4+ T cells at mucosal sites. The interaction between STI burden and HIV transmission is not incidental — it is a core reason why the geographic patterns of syphilis and HIV overlap so closely, and why STI control is considered an integral component of HIV prevention strategy by the CDC.

• Pelvic inflammatory disease: estimated 1 million PID cases per year in the US, the majority attributable to chlamydia and gonorrhea; 20% of affected women experience infertility
• Ectopic pregnancy: 9% of PID cases result in ectopic pregnancy; leading cause of pregnancy-related first-trimester mortality in the US
• Epididymitis: untreated chlamydia and gonorrhea in men causes testicular inflammation; estimated 600,000 cases/year in the US
• Congenital syphilis: 3,882 cases in 2023; stillbirth in ~40% of untreated pregnancies; $16,000+ per case in direct treatment costs
• HIV co-infection risk: active STI increases HIV acquisition and transmission risk 2–5 times
• HPV-attributable cancers: 36,000 per year in the US; largely preventable with vaccination and screening

Testing remains the primary intervention

The scale of the US STI epidemic — 20 million new infections per year, rising syphilis, antibiotic-resistant gonorrhea, a congenital syphilis surge — can make the problem seem intractable. It is not. Every STI discussed in this article is either curable with antibiotics or controllable with medication to the point where transmission is eliminated. The gap between the epidemic as it exists and the epidemic as it could be is almost entirely explained by a single variable: testing. Infections that are tested are diagnosed. Infections that are diagnosed are treated. Infections that are treated stop transmitting.

Routine, risk-appropriate STI screening is the single highest-impact intervention available to individual sexually active adults. The USPSTF provides screening recommendations grounded in the strongest available evidence — annual chlamydia and gonorrhea screening for sexually active women under 25, HIV screening for all adults at least once, syphilis screening in pregnancy. For sexually active adults with new or multiple partners, testing every 3–6 months is appropriate. If you're not sure what tests apply to your situation, this guide maps your exposures to the right tests. For how often to get tested, frequency depends on risk profile and partner count. Finding a confidential testing location is the first step — search for STD testing near you to get started.