Unprotected sex affects different groups in different ways, from young people to communities facing greater disparities. In the US, rates are higher for young women and for people in rural areas, while HIV from unprotected sex concentrates in specific populations. Globally, unprotected vaginal sex is a major driver of HIV transmission in heterosexual couples, and many young people report recent unprotected sex. This page brings together who is affected, where risks are highest, and the real-world outcomes, including HIV, other STIs, and unintended pregnancy costs.
Key Takeaways
- US women aged 15-24 have 2.5 times higher unprotected sex rates than older, CDC
- Black Americans 13% of population but 42% of new HIV from unprotected sex, CDC 2022
- Women in rural US 1.8 times more likely to have unprotected sex than urban, NSFG
- Globally, unprotected vaginal sex accounts for 80-90% of HIV transmissions in heterosexual couples according to UNAIDS data
- In the US, 2021 CDC data shows 36,136 new HIV diagnoses, with 67% attributed to male-to-male sexual contact without consistent condom use
- Chlamydia infection rates from unprotected sex rose 5% in Europe from 2019-2022, affecting 1 in 20 young adults, per ECDC surveillance
- Unprotected sex leads to $16 billion annual US STI treatment costs, CDC 2021
- Lifetime HIV cost per person from unprotected sex $400,000+ in US, CDC
- Unintended pregnancies cost EU €11.6 billion yearly in health/social services, WHO Europe
- 23.8% of US women aged 15-44 had unprotected sex at last intercourse, NSFG 2015-2019
- Globally, 40% of sexually active youth report unprotected sex in past month, WHO 2022
- In US high schools, 30% of students had sex without condom last time, YRBS 2021
- In the US, 45% of pregnancies among teens aged 15-19 are unintended due to unprotected sex, per Guttmacher Institute 2023
- Globally, 121 million unintended pregnancies occur yearly from unprotected sex, adding 73 million abortions, Lancet 2022
- Unprotected sex leads to 6 million unintended pregnancies annually in the US, CDC 2021 data
Unprotected sex drives major HIV and STI burdens and millions of unintended pregnancies, especially among young people.
Related reading
01 · Category
Demographic Variations30 stats
01
US women aged 15-24 have 2.5 times higher unprotected sex rates than older, CDC
02
Black Americans 13% of population but 42% of new HIV from unprotected sex, CDC 2022
03
Women in rural US 1.8 times more likely to have unprotected sex than urban, NSFG
04
MSM account for 69% of new US HIV diagnoses from unprotected sex, CDC
05
Latinas in US have 20% higher unintended pregnancy from unprotected sex, Guttmacher
06
Adolescents 10-19 represent 12% global population but 28% unsafe sex risks, WHO
07
Low-income US households 40% more unprotected sex incidents, NSFG data
08
Transgender women 49 times higher HIV risk from unprotected sex vs cis men, CDC
09
In sub-Saharan Africa, girls 15-24 3 times more HIV from unprotected sex than boys, UNAIDS
10
US Native Americans 2.1 times higher chlamydia rates from unprotected sex, IHS
11
Elderly 50+ MSM 20% report unprotected sex, higher than expected, CDC NHBS
12
Single parents 35% more likely to engage in unprotected casual sex, Pew Research
13
College-educated US adults 25% less unprotected sex than non-college, NSFG
14
Immigrants in Europe 1.5 times higher STI from unprotected sex, ECDC
15
US Southern states 30% higher teen unprotected sex rates, CDC
16
Bisexual women 2x unprotected sex partners vs straight, NSFG
17
Prisoners post-release 5x higher unprotected sex risk, BJS
18
LGBTQ+ youth 25% more unprotected sex than hetero peers, CDC YRBS
19
Overweight US adults 15% higher unprotected sex frequency, NHANES
20
Married US couples 60% report unprotected sex regularly, NSFG
21
Refugee women 40% higher unintended pregnancy from unprotected sex, UNHCR
22
Military personnel 22% report unprotected sex abroad, DoD surveys
23
Disabled adults 30% less condom use i.e. more unprotected, CDC
24
Urban poor in India 45% unprotected sex rate vs 20% urban rich, NFHS
25
Heterosexual men over 50 18% unprotected with younger partners, Kinsey
26
Asian Americans lowest unprotected sex rates at 12%, NSFG disparities
27
Sex workers clients 50% demand unprotected sex, UNAIDS
28
In US, men 25-34 peak unprotected sex age group at 28%, NSFG
29
Lesbians report 10% higher unprotected sex with toys sharing, NSFG
30
Rural African American women 3x higher HIV from unprotected sex, CDC
Interpretation
Demographic Variations Interpretation
Demographic differences sharply shape unprotected sex outcomes, such as US women aged 15 to 24 having rates 2.5 times higher than older groups and adolescents 10 to 19 making up just 12% of the global population while accounting for 28% of unsafe sex risks.
02 · Category
Hiv/sti Risks30 stats
01
Globally, unprotected vaginal sex accounts for 80-90% of HIV transmissions in heterosexual couples according to UNAIDS data
02
In the US, 2021 CDC data shows 36,136 new HIV diagnoses, with 67% attributed to male-to-male sexual contact without consistent condom use
03
Chlamydia infection rates from unprotected sex rose 5% in Europe from 2019-2022, affecting 1 in 20 young adults, per ECDC surveillance
04
Gonorrhea cases linked to unprotected anal sex increased by 28% among MSM in the UK between 2020-2023, British Health Security Agency reports
05
Syphilis transmission via unprotected sex surged 74% in the US from 2017-2021, with 176,713 cases in 2021 per CDC
06
HPV-related cancers from persistent unprotected sex infections cause 36,000 cases annually in the US, CDC estimates
07
Herpes simplex virus type 2 prevalence from unprotected sex is 11.9% globally in adults 15-49, WHO 2020 data
08
Unprotected sex contributes to 50% of bacterial vaginosis cases in women aged 15-44, per NIH studies
09
Trichomoniasis from unprotected sex infects 156 million people yearly worldwide, CDC global health data
10
Unprotected oral sex increases HPV transmission risk by 3.4 times in partners, per Journal of Infectious Diseases study
11
Hepatitis B from unprotected sex accounts for 20-30% of chronic cases in high-prevalence areas, WHO
12
Unprotected sex with multiple partners raises gonorrhea acquisition risk 5-fold, per Lancet Infectious Diseases
13
Mycoplasma genitalium from unprotected sex detected in 1-6% of asymptomatic women, ECDC data
14
Unprotected sex linked to 40% of pelvic inflammatory disease cases leading to infertility, ACOG
15
HIV viral load >100,000 copies/ml from unprotected sex increases transmission risk 10-fold, per NEJM
16
Unprotected receptive anal sex has 18 times higher HIV risk than vaginal, CDC estimates
17
Chlamydia reinfection from repeated unprotected sex occurs in 20% within 6 months, CDC
18
1 in 6 Americans aged 14-49 has genital herpes from unprotected sex history, CDC 2018
19
Unprotected sex drives 85% of new HIV infections in sub-Saharan Africa among young women, UNAIDS
20
Syphilis congenital transmission from maternal unprotected sex affects 1 in 10 cases, WHO
21
Unprotected sex with infected partner gives 0.08% per-act HIV risk for insertive vaginal, CDC
22
Gonorrhea antimicrobial resistance from unprotected sex spread rose 10% globally 2018-2022, WHO
23
HPV vaccination reduces unprotected sex-related cervical cancer by 90%, CDC
24
Unprotected sex causes 374 million new curable STI cases yearly worldwide, WHO 2020
25
Bacterial STIs from unprotected sex increase HIV acquisition 2-5 times, per meta-analysis in AIDS
26
Unprotected sex prevalence correlates with 25% higher STI rates in urban youth, CDC YRBS 2021
27
Receptive penile-oral HIV risk from unprotected sex is 0.04% per act, CDC
28
Unprotected sex with asymptomatic carriers spreads chlamydia in 70% of cases undetected, NIH
29
Global syphilis cases from unprotected sex hit 7.1 million in 2020 among 15-49 year olds, WHO
30
Unprotected anal sex HIV risk for bottom partner is 1.38% per act, CDC meta-analysis
Interpretation
Hiv/sti Risks Interpretation
Across regions, the STI and HIV burden linked to unprotected sex is rising fast, like syphilis transmissions surging 74% in the US from 2017 to 2021 with 176,713 cases in 2021, reinforcing that HIV/STI risks remain strongly tied to inconsistent protection.
03 · Category
Health And Economic Impacts20 stats
01
Unprotected sex leads to $16 billion annual US STI treatment costs, CDC 2021
02
Lifetime HIV cost per person from unprotected sex $400,000+ in US, CDC
03
Unintended pregnancies cost EU €11.6 billion yearly in health/social services, WHO Europe
04
Chlamydia complications from unprotected sex cost US $516 million annually, CDC
05
Global economic loss from HIV via unprotected sex $1 trillion by 2025, UNAIDS
06
Infertility treatment post-unprotected sex PID costs $2 billion US yearly, ASRM
07
HPV cancers from unprotected sex healthcare burden $8 billion US lifetime, CDC
08
Lost productivity from STIs $15.5 billion US 2018, adjusted for unprotected sex, CDC
09
Maternal mortality from unintended high-risk pregnancies post-unprotected sex: 800 women/day globally, WHO
10
US teen births from unprotected sex cost $9.4 billion public annually, HHS
11
Gonorrhea treatment resistance from unprotected spread adds $1 billion US costs, CDC
12
HIV PrEP prevents 37% infections but unprotected sex non-adherence costs $5 billion saved missed, CDC
13
Cervical cancer screening/treatment post-HPV unprotected sex: $6 billion US/year, NCI
14
Global contraception investment averts $5.6per $1 from unprotected sex pregnancies, Guttmacher
15
Syphilis outbreak response from unprotected sex surges US costs to $38 million in 2021 alone, CDC
16
Mental health burden: 20% depression increase post-STI from unprotected sex, JAMA Psychiatry
17
US Medicaid spends $2.1 billion on STI services linked to unprotected sex, KFF
18
Long COVID-like chronic fatigue in 10% post-herpes reactivation from unprotected sex, NIH
19
Abortion services post-unprotected sex unintended pregnancy: $1.2 billion US 2021, Guttmacher
20
Partner notification programs for STIs from unprotected sex cost $300 million EU yearly, ECDC
Interpretation
Health And Economic Impacts Interpretation
For the health and economic impacts of unprotected sex, the burden is massive and ongoing, with US STI treatment alone costing $16 billion each year and HIV driving $400,000 plus lifetime costs per person, while worldwide economic losses from HIV are projected to reach $1 trillion by 2025.
More related reading
04 · Category
Prevalence Rates30 stats
01
23.8% of US women aged 15-44 had unprotected sex at last intercourse, NSFG 2015-2019
02
Globally, 40% of sexually active youth report unprotected sex in past month, WHO 2022
03
In US high schools, 30% of students had sex without condom last time, YRBS 2021
04
19% of US adults aged 18-44 report recent unprotected sex with casual partners, Kinsey Institute
05
Europe: 37% of young adults 18-24 had unprotected sex past year, ESSENSE study
06
In India, 24% of married women aged 15-49 report unprotected sex always, NFHS-5
07
US college students: 42% engaged in unprotected sex last 30 days, per NCHA 2022
08
Globally, 222 million women in unions have unmet condom needs leading to unprotected sex, UN
09
UK: 1 in 5 young people 16-24 report unprotected sex with new partners, Natsal-3
10
In Brazil, 35% of MSM report unprotected anal sex past 6 months, IBGE survey
11
US adults: 15% always use condoms, meaning 85% have unprotected sex episodes, NSFG
12
Africa: 28% of adolescent girls report first sex unprotected, DHS surveys
13
Australia: 22% of sexually active 16-29 year olds had unprotected sex last week, ABS
14
In China, 60% of unmarried youth report unprotected premarital sex, Lancet study
15
US women: 12% report unprotected sex with non-steady partner past year, NSFG 2019
16
Globally, alcohol-influenced unprotected sex reported by 25% of youth, WHO
17
Canada: 31% of 15-24 year olds had unprotected sex past year, CCHS
18
In South Africa, 38% of adults report inconsistent condom use i.e. unprotected sex, HSRC
19
US MSM: 44% report unprotected anal sex past 12 months, CDC NHBS 2022
20
Europe: 20% of women 18-49 report unprotected sex at conception of last child, Eurostat
21
Mexico: 27% of youth 15-19 had unprotected sex debut, ENSANUT
22
Drug use correlates with 50% higher unprotected sex rates among US youth, SAMHSA
23
In Russia, 45% of young adults report frequent unprotected sex, RLMS-HSE
24
Global average: 1 in 4 sexual encounters unprotected among unmarried, DHS analysis
25
US Hispanics: 28% report unprotected sex last 3 months, NHANES
26
Japan: 15% of unmarried adults 18-39 report unprotected casual sex, JGSS
27
18% of US adults 25-44 never use condoms, leading to unprotected sex, NSFG 2023 update
28
In Nigeria, 41% of women 15-49 report unprotected sex with husband last time, DHS 2018
29
Teen girls in US: 21% had unprotected sex past 3 months, YRBS 2023
30
Lifetime unprotected sex exposure 70% among sexually experienced US adults 18-59, NHANES
Interpretation
Prevalence Rates Interpretation
Across multiple regions, the prevalence of unprotected sex is high and persistent, with figures like 40% of sexually active youth globally reporting unprotected sex in the past month and 30% of US high school students reporting no condom at last sex.
05 · Category
Unintended Pregnancy29 stats
01
In the US, 45% of pregnancies among teens aged 15-19 are unintended due to unprotected sex, per Guttmacher Institute 2023
02
Globally, 121 million unintended pregnancies occur yearly from unprotected sex, adding 73 million abortions, Lancet 2022
03
Unprotected sex leads to 6 million unintended pregnancies annually in the US, CDC 2021 data
04
49% of pregnancies in women under 30 are unplanned from inconsistent condom use, Guttmacher
05
In low-income countries, unprotected sex causes 60% of maternal deaths via unintended high-risk pregnancies, WHO
06
US teen pregnancy rate from unprotected sex dropped 75% since 1991 to 13.5 per 1,000 in 2021, CDC
07
75% of unintended pregnancies in Europe result from no contraception or incorrect use during sex, EU data
08
Unprotected sex accounts for 85% of repeat pregnancies in US adolescents within 2 years, JAMA Pediatrics
09
Globally, 218 million women have unmet need for contraception leading to unprotected sex pregnancies, UN 2022
10
In India, 50% of women aged 15-24 report unprotected sex in last intercourse, NFHS-5 survey
11
US abortion rate 11.0 per 1,000 women aged 15-44 in 2021 mostly from unprotected sex, Guttmacher
12
Unintended pregnancies cost US $21 billion yearly in public funds from unprotected sex, NASHP
13
4 in 10 US pregnancies are unintended, highest among 18-24 year olds from unprotected sex, Guttmacher 2022
14
In sub-Saharan Africa, unprotected sex leads to 28 unintended pregnancies per 100 women yearly, Guttmacher
15
Emergency contraception post-unprotected sex prevents 75-89% of expected pregnancies, WHO
16
30% of US women experience unintended pregnancy by age 20 from unprotected sex, CDC NSFG
17
Latin America sees 35 million unintended pregnancies yearly from low condom use, Lancet
18
Unprotected sex during ovulation doubles pregnancy risk per cycle to 30%, fertility studies
19
62% of unintended US pregnancies end in birth or abortion from condom failure, Guttmacher
20
In Australia, 1 in 3 pregnancies unintended due to unprotected sex, AIHW 2022
21
Unprotected sex causes 50% higher unintended pregnancy rates in unmarried couples, NSFG data
22
Canada reports 25% unintended pregnancy rate from inconsistent protection, CIHI
23
41% of unintended pregnancies worldwide occur in 15-24 year olds from unprotected sex, UNFPA
24
Perfect-use condom failure leads to 2/100 women pregnant yearly from unprotected acts, CDC
25
In the US, Black women have 1.5 times higher unintended pregnancy rate from unprotected sex disparities, CDC
26
Globally, withdrawal method during unprotected sex fails 22% yearly, WHO
27
55% of pregnancies after rape are from unprotected sex assaults, per RAINN data
28
US fertility rate decline to 1.64 births per woman partly due to more protected sex, CDC 2023
29
Unprotected sex in first trimester increases miscarriage risk by 15% if unintended, ACOG
Interpretation
Unintended Pregnancy Interpretation
Even though the US teen pregnancy rate tied to unprotected sex has fallen 75% since 1991 to 13.5 per 1,000 in 2021, unprotected sex still drives huge unintended pregnancy numbers including 45% of teen pregnancies in the US and 121 million worldwide each year.
Reference
Cite This Report
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APA
Stefan Wendt. (2026, February 13). Unprotected Sex Statistics. Gitnux. https://gitnux.org/unprotected-sex-statistics
MLA
Stefan Wendt. "Unprotected Sex Statistics." Gitnux, 13 Feb 2026, https://gitnux.org/unprotected-sex-statistics.
Chicago
Stefan Wendt. 2026. "Unprotected Sex Statistics." Gitnux. https://gitnux.org/unprotected-sex-statistics.
Sources & references
48 datasets cited across this report · attribution is report-level