While millions silently carry infections without knowing it, our world saw nearly two and a half million cases of just three common STIs reported in the United States in 2021 alone.
Key Takeaways
- In 2021, there were an estimated 2,512,391 cases of chlamydia, gonorrhea, and syphilis reported in the United States
- Globally, more than 1 million STIs are acquired every day, mostly asymptomatic
- In the US, chlamydia was the most common notifiable STI with 1,644,427 cases in 2021
- In 2021, US chlamydia rate was 499.3 per 100,000 population
- Gonorrhea incidence rate in US 2021 was 216.4 per 100,000
- Syphilis total rate in US 2021 was 53.7 per 100,000
- Women 15-24 in US have chlamydia rates 4 times higher than older women
- In 2021, US chlamydia rate for Black females was 1,127.6 per 100,000 vs 166.4 for White females
- Gonorrhea rates in US Black males 15-24 were 2,026 per 100,000 in 2021
- Gonorrhea multidrug-resistant strains 3.4% in US 2021
- Chlamydia trachomatis causes 90% of bacterial STIs in young women
- Neisseria gonorrhoeae azithromycin resistance 5.5% in US 2021
- US chlamydia cases decreased 5% from 2020 to 2021 but still high
- Gonorrhea cases rose 28% in US adolescents 15-24 from 2018-2021
- Syphilis cases increased 80% in US 2018-2022
STIs are a global crisis, with millions of new infections occurring silently each year.
Demographic Variations
- Women 15-24 in US have chlamydia rates 4 times higher than older women
- In 2021, US chlamydia rate for Black females was 1,127.6 per 100,000 vs 166.4 for White females
- Gonorrhea rates in US Black males 15-24 were 2,026 per 100,000 in 2021
- MSM accounted for 53% of primary/secondary syphilis cases in US 2021
- US congenital syphilis highest among American Indian/Alaska Native at 291.2 per 100,000 live births 2021
- Globally, adolescent girls aged 15–19 account for 21% of new HIV infections in Eastern and Southern Africa
- In US, genital herpes seroprevalence HSV-2 is 15.7% in non-Hispanic Blacks vs 3.8% in non-Hispanic Whites
- HPV prevalence higher in US Hispanic women at 47.3% vs 41.7% non-Hispanic White
- In Europe 2022, gonorrhoea highest in men 20–24 years at 1,332 cases per 100,000
- UK 2022 gonorrhoea diagnoses 82% in heterosexuals under 25
- Australia chlamydia highest in 15-29 year olds, 70% of cases
- Canada STI rates highest in Indigenous populations, 5 times national average for chlamydia
- In South Africa, women 15-24 have HIV incidence 8 times higher than men same age
- US syphilis rates 8 times higher in Black males than White males 2021
- Globally, 50% of curable STIs in South-East Asia region among 15-24 year olds
- In US, chlamydia positivity highest in 15-19 females at clinics 23.6%
- MSM gonorrhea rates in UK 2022 were 1,040 per 100,000 vs 36 in heterosexual men
- HPV vaccine uptake lower in US low-income groups, leading to higher cervical dysplasia
- In Brazil, HIV prevalence 0.6% overall but 18% among transgender women
- Europe syphilis 2022 highest in MSM at 92% of cases in some countries
- US 2021 gonorrhea in adolescents 15-24 was 48% of total cases
- Global HIV among sex workers averages 30-50% prevalence in many regions
- In India, STI prevalence higher in urban migrants 12.5% vs rural 6%
- Congenital syphilis in US Hispanics 2021 rate 100.8 per 100,000 live births
- Australia syphilis rates 10 times higher in Aboriginal populations
- In 15-24 year old US females, 40% have ever had HPV
- MSM account for 69% of new HIV diagnoses in US 2021
- Black youth 15-24 have syphilis rates 4x White youth in US
- Women living with HIV globally outnumber men in adolescents
- In US clinics, chlamydia rates highest in Black females 15-24 at 25.9%
Demographic Variations Interpretation
These statistics expose a harsh reality: our sexual health outcomes are shamefully stratified, not by personal responsibility alone, but by the intersecting vectors of age, race, ethnicity, sexual orientation, and socioeconomic access, revealing a pandemic of inequity hiding in plain sight.
Incidence Rates
- In 2021, US chlamydia rate was 499.3 per 100,000 population
- Gonorrhea incidence rate in US 2021 was 216.4 per 100,000
- Syphilis total rate in US 2021 was 53.7 per 100,000
- Globally, new syphilis infections total 8 million annually in 15-49 age group
- Chlamydia incidence worldwide 129 million new cases per year
- Gonorrhoea new cases globally 82 million yearly
- Trichomoniasis incidence 156 million new cases annually worldwide
- HIV new infections globally dropped to 1.5 million in 2022 from 2.1 million in 2010
- In US MSM, gonorrhea rate was 8,040 per 100,000 in 2021
- US women aged 15-24 account for nearly half of chlamydia cases, rate 3,067 per 100,000
- Congenital syphilis rate in US 2021 was 59.9 per 100,000 live births
- Europe gonorrhea incidence 48% increase in 2022 to 48 cases per 100,000
- UK gonorrhea rate 2022 was 70.0 per 100,000
- Australia chlamydia rate 2022 was 309.4 per 100,000
- Canada chlamydia incidence 2022 was 273 per 100,000
- HSV-2 incidence globally estimated at 23.6 million symptomatic episodes yearly
- US primary/secondary syphilis rate among women 2021 was 25.5 per 100,000
- Global HPV incidence linked to 620,000 cervical cancer cases yearly
- Hepatitis C new infections worldwide 1.5 million per year
- In 2022, UK syphilis diagnoses 8,724, rate 12.5 per 100,000
- Australia's gonorrhea rate 2022 was 112.2 per 100,000
- Canada gonorrhea rate 2022 64 per 100,000
- In US, chlamydia rates highest in 20-24 year olds at 2,512 per 100,000 females
- MSM primary/secondary syphilis rate US 2021 was 3,017 per 100,000
- Global new HIV infections among young women 25% of total in 2022
- Europe chlamydia cases 2022 216,508, stable
- Trichomoniasis rate in US women higher, estimated 3.1 million prevalent cases
- US gonorrhea rates in Black females 15-24 were 2,512 per 100,000 in 2021
- Congenital syphilis in US increased 167% from 2017 to 2021
- In the US, 2021 chlamydia cases among females were 1,065,132
- Gonorrhea cases in US males 2021: 462,634
- Chlamydia accounts for 75% of STI clinic diagnoses in US adolescents
- In US, syphilis rates among Black males 15-24 were 131.6 per 100,000 in 2021
- Global syphilis incidence rate 0.5% in 15-49 year olds
Incidence Rates Interpretation
While it’s genuinely encouraging to see global HIV infections declining, the sheer volume of other STIs screaming from these statistics suggests humanity is, on the whole, being profoundly careless with a baffling dedication to ignoring both condoms and common sense.
Prevalence Statistics
- In 2021, there were an estimated 2,512,391 cases of chlamydia, gonorrhea, and syphilis reported in the United States
- Globally, more than 1 million STIs are acquired every day, mostly asymptomatic
- In the US, chlamydia was the most common notifiable STI with 1,644,427 cases in 2021
- Worldwide, 374 million new cases of four curable STIs (chlamydia, gonorrhoea, syphilis, trichomoniasis) occurred in 2020 among adults aged 15–49 years
- In 2021, US gonorrhea cases reached 716,030, the highest number reported since 1991
- Syphilis cases in the US totaled 176,713 in 2021, including 2,457 cases of congenital syphilis
- In Europe, 2022 saw over 70,000 gonorrhoea cases reported, a 48% increase from 2021
- UK reported 49,209 new gonorrhoea diagnoses in 2022, highest since 1918 records began
- In Australia, 2022 chlamydia notifications were 85,825, stable from previous years
- Canada reported 108,786 chlamydia cases in 2022
- In 2020, an estimated 30.1% of new HIV infections globally were among key populations including sex workers
- HPV prevalence among US females aged 14-59 is 42.5% based on NHANES 2013-2014
- Trichomoniasis causes 156 million new cases annually worldwide
- In sub-Saharan Africa, HSV-2 prevalence among adults is 31-48%
- US primary and secondary syphilis rates were 53.7 per 100,000 in 2021
- Globally, 6% of people aged 15-49 have syphilis
- In 2021, congenital syphilis cases in US increased 30% to 2,457
- Europe reported 37,889 syphilis cases in 2022, up 34% from 2021
- Australia's 2022 syphilis notifications were 6,978
- In the US, 2021 saw 11,941 cases of primary and secondary syphilis among MSM
- Global HIV prevalence is 0.7% among adults 15-49 years, totaling 38.4 million people in 2021
- Hepatitis B prevalence globally is 257 million chronic carriers
- In the US, genital herpes prevalence is 11.9% for ages 14-49
- WHO estimates 490 million non-viral STI cases yearly worldwide
- In 2022, UK chlamydia diagnoses were 217,369
- Canada's 2022 gonorrhea cases were 25,475
- In India, estimated 31.5 million STI cases annually
- Brazil reported 236,272 HIV cases cumulatively by 2022
- South Africa has 7.5 million HIV positive people, prevalence 19.5% in adults
Prevalence Statistics Interpretation
While these numbers paint a grim picture of a global silent epidemic, it's clear that our collective complacency is being outmatched by the relentless spread of sexually transmitted infections.
Specific STI Data
- Gonorrhea multidrug-resistant strains 3.4% in US 2021
- Chlamydia trachomatis causes 90% of bacterial STIs in young women
- Neisseria gonorrhoeae azithromycin resistance 5.5% in US 2021
- Treponema pallidum causes syphilis, with 7% neurosyphilis in primary/secondary cases
- HIV-1 subtype B dominant in US, 80% of cases
- Human papillomavirus types 16 and 18 cause 70% of cervical cancers
- Herpes simplex virus type 2 responsible for 90% of genital herpes recurrences
- Trichomonas vaginalis infection doubles HIV acquisition risk in women
- Hepatitis B virus chronic infection in 5-10% adults post-acute infection
- Hepatitis C virus genotype 1 prevalent in 60% US cases
- Mycoplasma genitalium detected in 15-20% non-chlamydial NGU cases
- Chlamydia screening positivity 10.5% in US family planning clinics 2021
- Gonorrhea cephalosporin MIC creep to 0.5 ug/mL in 8.6% US isolates 2021
- Syphilis RPR titers >1:32 in 25% primary cases
- HIV viral load >100,000 copies/mL increases transmission 10-fold
- HPV vaccination prevents 90% of HPV-related cancers with 3 doses
- HSV-1 causes 50% of new genital herpes cases in US
- Trichomoniasis metronidazole resistance 4-10% in US
- HBV vaccine efficacy 95% in preventing perinatal transmission
- HCV spontaneous clearance in 25-45% acute cases
- M. genitalium macrolide resistance 40-50% globally
- Chlamydia LGV serovars rare but increasing in MSM
- Gonococcal pharyngeal infections 10-15% asymptomatic in MSM
- Syphilis Jarisch-Herxheimer reaction in 10-20% treated early syphilis
- HIV PrEP reduces acquisition by 99% with high adherence
- HPV 6/11 cause 90% genital warts
- HSV shedding asymptomatic 10-20% days in HSV-2 positive
- Trichomoniasis prevalence 2.1% US females 14-49 NHANES
- HBV HBsAg positivity 3.5% global adults
- HCV RNA positivity 1% US adults NHANES 2011-2014
- M. genitalium 1-6% prevalence general population, higher in STI clinics
Specific STI Data Interpretation
The sobering truth behind these numbers is that our most intimate moments are now a complex battlefield where bacteria and viruses are rapidly outmaneuvering our medical defenses, demanding smarter prevention, sharper diagnostics, and more resilient treatments.
Trends and Interventions
- US chlamydia cases decreased 5% from 2020 to 2021 but still high
- Gonorrhea cases rose 28% in US adolescents 15-24 from 2018-2021
- Syphilis cases increased 80% in US 2018-2022
- Global HIV new infections declined 22% 2010-2021
- HPV vaccination led to 88% drop in vaccine-type HPV in US teen girls 2006-2016
- Condom use prevents 80-95% HIV transmission per act
- PrEP use increased 50% in US 2020-2021
- Europe STI surveillance shows 25% rise in STIs 2021-2022 post-COVID
- UK chlamydia diagnoses fell 20% during COVID lockdowns, rebounded 2022
- Australia Doxy-PEP trials show 65% reduction gonorrhea/chlamydia in MSM
- Global syphilis elimination target 90% reduction by 2030 via WHO strategy
- US congenital syphilis action plan aims 50% reduction by 2025
- HIV treatment as prevention reduced incidence 50% in communities
- HPV vaccine coverage 60% US teens complete series 2021
- Antibiotic resistance in gonorrhea tripled 2000-2020 globally
- Screening programs reduced chlamydia complications 20-30% in young women
- PrEP awareness 80% but uptake 3% among US MSM at risk 2021
- Global 95-95-95 HIV targets met in 25 countries by 2023
- Canada STI rates stable but syphilis up 92% 2018-2022
- Diphtheria PEP reduced bacterial STIs 66% in Australian trial MSM
- US gonorrhea decreased 5% 2020-2021 due to COVID behaviors
- WHO estimates need 10 million more syphilis tests yearly for elimination
- HSV suppressive therapy reduces shedding 50%, transmission 48%
- Trichomoniasis screening not routine but reduces preterm birth risk
- HBV vaccination coverage 85% global infants by 2022
- HCV cure rates 95% with DAAs, eliminated mother-to-child transmission in pilots
Trends and Interventions Interpretation
While we celebrate the victories of vaccines and treatments in our fight against STIs, the sobering surge of syphilis and gonorrhea alongside persistent barriers to prevention tools like PrEP reveals a critical and ongoing battle where complacency is not an option.
Sources & References
- Reference 1CDCcdc.govVisit source
- Reference 2WHOwho.intVisit source
- Reference 3ECDCecdc.europa.euVisit source
- Reference 4GOVgov.ukVisit source
- Reference 5HEALTHhealth.gov.auVisit source
- Reference 6HEALTH-INFOBASEhealth-infobase.canada.caVisit source
- Reference 7UNAIDSunaids.orgVisit source
- Reference 8NCBIncbi.nlm.nih.govVisit source
- Reference 9GOVgov.brVisit source
- Reference 10NICDnicd.ac.zaVisit source
- Reference 11TGAtga.gov.auVisit source