STIs such as chlamydia, gonorrhea, and syphilis affect people across ages and countries, but the burden is uneven. In the US, young adults and specific communities face much higher rates—for example, Black females had 1,127.6 chlamydia cases per 100,000 in 2021. The page also highlights key forces behind spread, including sexual network patterns (like MSM accounting for 53% of primary/secondary syphilis cases in 2021) and antimicrobial resistance.
Key Takeaways
- 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
- 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
- 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
- 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
US chlamydia, gonorrhea, and syphilis rates remain high and worsening for key groups, fueling persistent STI transmission.
Related reading
01 · Category
Demographic Variations30 stats
01
Women 15-24 in US have chlamydia rates 4 times higher than older women
02
In 2021, US chlamydia rate for Black females was 1,127.6 per 100,000 vs 166.4 for White females
03
Gonorrhea rates in US Black males 15-24 were 2,026 per 100,000 in 2021
04
MSM accounted for 53% of primary/secondary syphilis cases in US 2021
05
US congenital syphilis highest among American Indian/Alaska Native at 291.2 per 100,000 live births 2021
06
Globally, adolescent girls aged 15–19 account for 21% of new HIV infections in Eastern and Southern Africa
07
In US, genital herpes seroprevalence HSV-2 is 15.7% in non-Hispanic Blacks vs 3.8% in non-Hispanic Whites
08
HPV prevalence higher in US Hispanic women at 47.3% vs 41.7% non-Hispanic White
09
In Europe 2022, gonorrhoea highest in men 20–24 years at 1,332 cases per 100,000
10
UK 2022 gonorrhoea diagnoses 82% in heterosexuals under 25
11
Australia chlamydia highest in 15-29 year olds, 70% of cases
12
Canada STI rates highest in Indigenous populations, 5 times national average for chlamydia
13
In South Africa, women 15-24 have HIV incidence 8 times higher than men same age
14
US syphilis rates 8 times higher in Black males than White males 2021
15
Globally, 50% of curable STIs in South-East Asia region among 15-24 year olds
16
In US, chlamydia positivity highest in 15-19 females at clinics 23.6%
17
MSM gonorrhea rates in UK 2022 were 1,040 per 100,000 vs 36 in heterosexual men
18
HPV vaccine uptake lower in US low-income groups, leading to higher cervical dysplasia
19
In Brazil, HIV prevalence 0.6% overall but 18% among transgender women
20
Europe syphilis 2022 highest in MSM at 92% of cases in some countries
21
US 2021 gonorrhea in adolescents 15-24 was 48% of total cases
22
Global HIV among sex workers averages 30-50% prevalence in many regions
23
In India, STI prevalence higher in urban migrants 12.5% vs rural 6%
24
Congenital syphilis in US Hispanics 2021 rate 100.8 per 100,000 live births
25
Australia syphilis rates 10 times higher in Aboriginal populations
26
In 15-24 year old US females, 40% have ever had HPV
27
MSM account for 69% of new HIV diagnoses in US 2021
28
Black youth 15-24 have syphilis rates 4x White youth in US
29
Women living with HIV globally outnumber men in adolescents
30
In US clinics, chlamydia rates highest in Black females 15-24 at 25.9%
Interpretation
Demographic Variations Interpretation
Demographic differences strongly shape STI burdens, with the most striking gaps showing up in young people and racial and ethnic groups such as 15 to 24 women having chlamydia rates four times higher than older women and Black females in 2021 facing 1,127.6 per 100,000 compared with 166.4 for White females.
02 · Category
Incidence Rates30 stats
01
In 2021, US chlamydia rate was 499.3 per 100,000 population
02
Gonorrhea incidence rate in US 2021 was 216.4 per 100,000
03
Syphilis total rate in US 2021 was 53.7 per 100,000
04
Globally, new syphilis infections total 8 million annually in 15-49 age group
05
Chlamydia incidence worldwide 129 million new cases per year
06
Gonorrhoea new cases globally 82 million yearly
07
Trichomoniasis incidence 156 million new cases annually worldwide
08
HIV new infections globally dropped to 1.5 million in 2022 from 2.1 million in 2010
09
In US MSM, gonorrhea rate was 8,040 per 100,000 in 2021
10
US women aged 15-24 account for nearly half of chlamydia cases, rate 3,067 per 100,000
11
Congenital syphilis rate in US 2021 was 59.9 per 100,000 live births
12
Europe gonorrhea incidence 48% increase in 2022 to 48 cases per 100,000
13
UK gonorrhea rate 2022 was 70.0 per 100,000
14
Australia chlamydia rate 2022 was 309.4 per 100,000
15
Canada chlamydia incidence 2022 was 273 per 100,000
16
HSV-2 incidence globally estimated at 23.6 million symptomatic episodes yearly
17
US primary/secondary syphilis rate among women 2021 was 25.5 per 100,000
18
Global HPV incidence linked to 620,000 cervical cancer cases yearly
19
Hepatitis C new infections worldwide 1.5 million per year
20
In 2022, UK syphilis diagnoses 8,724, rate 12.5 per 100,000
21
Australia's gonorrhea rate 2022 was 112.2 per 100,000
22
Canada gonorrhea rate 2022 64 per 100,000
23
In US, chlamydia rates highest in 20-24 year olds at 2,512 per 100,000 females
24
MSM primary/secondary syphilis rate US 2021 was 3,017 per 100,000
25
Global new HIV infections among young women 25% of total in 2022
26
Europe chlamydia cases 2022 216,508, stable
27
Trichomoniasis rate in US women higher, estimated 3.1 million prevalent cases
28
US gonorrhea rates in Black females 15-24 were 2,512 per 100,000 in 2021
29
Congenital syphilis in US increased 167% from 2017 to 2021
30
In the US, 2021 chlamydia cases among females were 1,065,132
Interpretation
Incidence Rates Interpretation
Within the incidence rates, the 2021 US burden is substantial at 499.3 chlamydia cases per 100,000 compared with 216.4 gonorrhea and 53.7 syphilis, and this national pattern mirrors the global scale where 129 million new chlamydia and 82 million gonorrhea cases occur each year.
03 · Category
Prevalence Statistics29 stats
01
In 2021, there were an estimated 2,512,391 cases of chlamydia, gonorrhea, and syphilis reported in the United States
02
Globally, more than 1 million STIs are acquired every day, mostly asymptomatic
03
In the US, chlamydia was the most common notifiable STI with 1,644,427 cases in 2021
04
Worldwide, 374 million new cases of four curable STIs (chlamydia, gonorrhoea, syphilis, trichomoniasis) occurred in 2020 among adults aged 15–49 years
05
In 2021, US gonorrhea cases reached 716,030, the highest number reported since 1991
06
Syphilis cases in the US totaled 176,713 in 2021, including 2,457 cases of congenital syphilis
07
In Europe, 2022 saw over 70,000 gonorrhoea cases reported, a 48% increase from 2021
08
UK reported 49,209 new gonorrhoea diagnoses in 2022, highest since 1918 records began
09
In Australia, 2022 chlamydia notifications were 85,825, stable from previous years
10
Canada reported 108,786 chlamydia cases in 2022
11
In 2020, an estimated 30.1% of new HIV infections globally were among key populations including sex workers
12
HPV prevalence among US females aged 14-59 is 42.5% based on NHANES 2013-2014
13
Trichomoniasis causes 156 million new cases annually worldwide
14
In sub-Saharan Africa, HSV-2 prevalence among adults is 31-48%
15
US primary and secondary syphilis rates were 53.7 per 100,000 in 2021
16
Globally, 6% of people aged 15-49 have syphilis
17
In 2021, congenital syphilis cases in US increased 30% to 2,457
18
Europe reported 37,889 syphilis cases in 2022, up 34% from 2021
19
Australia's 2022 syphilis notifications were 6,978
20
In the US, 2021 saw 11,941 cases of primary and secondary syphilis among MSM
21
Global HIV prevalence is 0.7% among adults 15-49 years, totaling 38.4 million people in 2021
22
Hepatitis B prevalence globally is 257 million chronic carriers
23
In the US, genital herpes prevalence is 11.9% for ages 14-49
24
WHO estimates 490 million non-viral STI cases yearly worldwide
25
In 2022, UK chlamydia diagnoses were 217,369
26
Canada's 2022 gonorrhea cases were 25,475
27
In India, estimated 31.5 million STI cases annually
28
Brazil reported 236,272 HIV cases cumulatively by 2022
29
South Africa has 7.5 million HIV positive people, prevalence 19.5% in adults
Interpretation
Prevalence Statistics Interpretation
From the prevalence perspective, the US saw 1,644,427 chlamydia cases in 2021 alongside 716,030 gonorrhea cases, showing how high-burden STIs remain widespread even as reporting reaches its highest gonorrhea level since 1991.
More related reading
04 · Category
Specific Sti Data30 stats
01
Gonorrhea multidrug-resistant strains 3.4% in US 2021
02
Chlamydia trachomatis causes 90% of bacterial STIs in young women
03
Neisseria gonorrhoeae azithromycin resistance 5.5% in US 2021
04
Treponema pallidum causes syphilis, with 7% neurosyphilis in primary/secondary cases
05
HIV-1 subtype B dominant in US, 80% of cases
06
Human papillomavirus types 16 and 18 cause 70% of cervical cancers
07
Herpes simplex virus type 2 responsible for 90% of genital herpes recurrences
08
Trichomonas vaginalis infection doubles HIV acquisition risk in women
09
Hepatitis B virus chronic infection in 5-10% adults post-acute infection
10
Hepatitis C virus genotype 1 prevalent in 60% US cases
11
Mycoplasma genitalium detected in 15-20% non-chlamydial NGU cases
12
Chlamydia screening positivity 10.5% in US family planning clinics 2021
13
Gonorrhea cephalosporin MIC creep to 0.5 ug/mL in 8.6% US isolates 2021
14
Syphilis RPR titers >1:32 in 25% primary cases
15
HIV viral load >100,000 copies/mL increases transmission 10-fold
16
HPV vaccination prevents 90% of HPV-related cancers with 3 doses
17
HSV-1 causes 50% of new genital herpes cases in US
18
Trichomoniasis metronidazole resistance 4-10% in US
19
HBV vaccine efficacy 95% in preventing perinatal transmission
20
HCV spontaneous clearance in 25-45% acute cases
21
M. genitalium macrolide resistance 40-50% globally
22
Chlamydia LGV serovars rare but increasing in MSM
23
Gonococcal pharyngeal infections 10-15% asymptomatic in MSM
24
Syphilis Jarisch-Herxheimer reaction in 10-20% treated early syphilis
25
HIV PrEP reduces acquisition by 99% with high adherence
26
HPV 6/11 cause 90% genital warts
27
HSV shedding asymptomatic 10-20% days in HSV-2 positive
28
Trichomoniasis prevalence 2.1% US females 14-49 NHANES
29
HBV HBsAg positivity 3.5% global adults
30
HCV RNA positivity 1% US adults NHANES 2011-2014
Interpretation
Specific Sti Data Interpretation
Across specific STI data, antimicrobial resistance and dominant pathogen types stand out, such as 3.4% multidrug resistant gonorrhea and 5.5% azithromycin resistance in the US in 2021 alongside HPV types 16 and 18 accounting for 70% of cervical cancers.
05 · Category
Trends And Interventions26 stats
01
US chlamydia cases decreased 5% from 2020 to 2021 but still high
02
Gonorrhea cases rose 28% in US adolescents 15-24 from 2018-2021
03
Syphilis cases increased 80% in US 2018-2022
04
Global HIV new infections declined 22% 2010-2021
05
HPV vaccination led to 88% drop in vaccine-type HPV in US teen girls 2006-2016
06
Condom use prevents 80-95% HIV transmission per act
07
PrEP use increased 50% in US 2020-2021
08
Europe STI surveillance shows 25% rise in STIs 2021-2022 post-COVID
09
UK chlamydia diagnoses fell 20% during COVID lockdowns, rebounded 2022
10
Australia Doxy-PEP trials show 65% reduction gonorrhea/chlamydia in MSM
11
Global syphilis elimination target 90% reduction by 2030 via WHO strategy
12
US congenital syphilis action plan aims 50% reduction by 2025
13
HIV treatment as prevention reduced incidence 50% in communities
14
HPV vaccine coverage 60% US teens complete series 2021
15
Antibiotic resistance in gonorrhea tripled 2000-2020 globally
16
Screening programs reduced chlamydia complications 20-30% in young women
17
PrEP awareness 80% but uptake 3% among US MSM at risk 2021
18
Global 95-95-95 HIV targets met in 25 countries by 2023
19
Canada STI rates stable but syphilis up 92% 2018-2022
20
Diphtheria PEP reduced bacterial STIs 66% in Australian trial MSM
21
US gonorrhea decreased 5% 2020-2021 due to COVID behaviors
22
WHO estimates need 10 million more syphilis tests yearly for elimination
23
HSV suppressive therapy reduces shedding 50%, transmission 48%
24
Trichomoniasis screening not routine but reduces preterm birth risk
25
HBV vaccination coverage 85% global infants by 2022
26
HCV cure rates 95% with DAAs, eliminated mother-to-child transmission in pilots
Interpretation
Trends And Interventions Interpretation
Across trends and interventions, prevention is clearly working in some places while other infections are still surging, as shown by the 88% drop in vaccine type HPV among US teen girls from 2006 to 2016 and the global 22% decline in new HIV infections from 2010 to 2021, alongside worsening US sexual health with syphilis up 80% from 2018 to 2022 and gonorrhea up 28% among adolescents 15 to 24 from 2018 to 2021.
Reference
Cite This Report
This report is designed to be cited. We maintain stable URLs and versioned verification dates. Copy the format appropriate for your publication below.
APA
Ryan Townsend. (2026, February 13). Sti Statistics. Gitnux. https://gitnux.org/sti-statistics
MLA
Ryan Townsend. "Sti Statistics." Gitnux, 13 Feb 2026, https://gitnux.org/sti-statistics.
Chicago
Ryan Townsend. 2026. "Sti Statistics." Gitnux. https://gitnux.org/sti-statistics.
Sources & references
11 datasets cited across this report · attribution is report-level