What are the Chances of Catching an STD when Traveling?

Instead of asking how possible it is to get an STD while traveling, it would be better to ask how possible it is to catch an STD per unprotected encounter with an infected partner. Women are known to have a higher risk of getting an STD than men due to the lining in the vagina being more susceptible to foreign bacterial development. Another factor to keep in mind is that most STDs are asymptomatic, where patients experience minimal or no symptoms at all. Current statistics show the chances of STDs per heterosexual encounter broken down by each condition:

Chlamydia: One of the most frequently reported in the United States, chlamydia has proven to be common among younger generations ages between 15 to 24. (2) Current studies rate the probability of someone getting the STD at 4.5% per sex act for both men and women. (3) Learn more about chlamydia from The Call-On-Doc Guide to Chlamydia. 

Gonorrhea: One of the most common STDs to be reported, gonorrhea has a high transmission rate in both men and women, being 20% to 30% and 60% to 90%, respectively, per sexual encounter. (4) Learn more about gonorrhea from The Call-On-Doc Guide to Gonorrhea. 

Herpes: Herpes is believed to have infected billions of people globally, with a significant percentage of people in the United States already infected with either HSV-1 or HSV-2. While male to female is up to 31% chance of transmission, female to male has a 4% chance. (5) While asymptomatic cases have a lower chance of passing on the STD, it's well documented that most cases are passed on while the infected partner is asymptomatic. Learn more about herpes from The Call-On-Doc Guide to Herpes. 

Human Immunodeficiency Viruses: In the United States and globally, HIV is responsible for hundreds of thousands of deaths annually, being the cause of the global AIDS pandemic of the 80’s and 90’s. While exposure per sexual encounter is currently measured at less than 1%, the condition has no cure and severely reduces a person’s quality of life if left untreated. (6) Learn more about the human immunodeficiency virus from The Call-On-Doc Guide to HIV. 

Human Papillomavirus: The most common sexually transmitted infection in the United States and globally, HPV runs a 3.5% chance for women and a 5.6% chance for men. (7) While research is still being conducted on the HPV transmission rate, the explanation for its aggressive transmission rate falls upon it being difficult to notice and often asymptomatic. Learn more about HPV from The Call-On-Doc Guide to Genital Warts. 

Mycoplasma Genitalium: Compared to other STDs, M. Genitalium was discovered relatively recently in the 1980s. It is considered a fastidious bacteria, meaning it grows slowly in the body after transmission. Often asymptomatic, it can result in complications when left untreated in some patients and is closely monitored by healthcare professionals due to its resistance to many antibiotics. While it has a relatively low transmission rate of 2.3% for women and 1.1% for men per sexual encounter, couples are known to have a higher chance of catching the STD due to the lack of initial symptoms for most people. (8) Learn more about M. genitalium from The Call-On-Doc Guide to Mycoplasma Genitalium. 

Syphilis: An STD closely monitored by the Department of Health and other agencies monitoring public health due to how it can develop in the human body, syphilis has recently experienced a resurgence in cases by around 80% more than normal between 2018 and 2022 among all age groups. In context, such numbers have not been seen since the 1950s, which is a major concern due to how the STD can damage everything from the brain, to the heart, internal organs, and more. (9) Having a high chance of spreading when a person has it, the transmission rate per sexual act can be as high as 20% to 30%. (10) Learn more about syphilis from The Call-On-Doc Guide to Syphilis. 

Trichomoniasis: Known to increase the chance of catching other STDs like HIV due to it inflaming the genitals, trichomoniasis often shows up as asymptomatic. (11) Unlike other STDs, which spread virally or bacterially, trichomoniasis is a parasite called Trichomonas vaginalis that mainly attacks the lower genital tract in women and the urethra in men. Spreading aggressively in most populations, the infection rate of the parasite is estimated to be 3.2% per sexual encounter. (12) Learn more about trichomoniasis from The Call-On-Doc Guide to Trichomoniasis. 

Alcohol and Drugs: Someone under the influence of substances like alcohol, stimulants, and opiates will struggle to control their impulses. (13) When relating it to STD transmission, such substances can influence a person’s ability to consider situations that may make them more vulnerable, like unprotected sex with someone you do not know or something similar. (14)

Gender: Women are far more vulnerable to sexually transmitted diseases than men due to differences in anatomy. Put simply, the vaginal microbiome is an easy place for bacteria to grow and flourish, while for men, bacteria have to travel through the longer urethra to gain entry. Additionally, the lining in the vagina is easy to access for an STD, being directly accessible during vaginal intercourse. (15)

Immune System Health: Like any other disease and infection, your immune system plays a crucial role in protecting your body from STDs. A healthy immune system can help recognize and fight off pathogens, including bacteria and viruses responsible for STIs, reducing the likelihood and severity of infection. Conversely, a compromised immune system, such as that seen in individuals with conditions like HIV/AIDS or those undergoing immunosuppressive therapy, may weaken the body's ability to defend against STIs, leading to an increased risk of infection and potential complications.

Multiple Partners: The more partners a person has sexual relations with, the greater the likelihood they will contract an STD. (16) 

Not Getting Tested: Young people ages 15 to 25 make up half of all STD cases, yet the vast majority of those in such an age group don’t seek out testing. (17) When it comes to when a person should be tested, the CDC recommends: 

• All adults and adolescents aged 13-64 should be tested for HIV at least once.
• Sexually active women under 25 should get tested annually for gonorrhea and chlamydia.
• Women aged 25 and older with risk factors (e.g., multiple partners) should also be tested annually.
• Pregnant individuals should be tested for syphilis, HIV, hepatitis B, and hepatitis C early in pregnancy. Chlamydia and gonorrhea testing is recommended for those at risk.
• Gay, bisexual, and other men who have sex with men should be tested annually for syphilis, chlamydia, and gonorrhea, with more frequent testing for those with multiple partners. HIV testing should be done at least annually. 
• Hepatitis C testing is recommended annually for MSM living with HIV.
• Anyone engaging in risky sexual behavior or sharing injection drug equipment should be tested for HIV annually.
• Individuals who have had oral or anal sex should discuss throat and rectal testing options with their healthcare provider.

Types of Sexual Activity: While it might be common knowledge, it should still be stated that a person can catch an STD not just by vaginal sex but also via oral and anal sex. In fact, unprotected anal sex increases the chance of catching an STD, especially HIV, chlamydia, and gonorrhea.

Unprotected Sex: Choosing to avoid the use of condoms, dental dams, and other forms of protection leaves a person directly susceptible to catching a sexually transmitted disease. Not just featuring a high protection rating against getting pregnant, condoms also block direct exposure to bodily fluids carrying the bacteria that spread STDs. 

According to the CDC, STD care cost Americans around the country a total of $16 billion due to treatment, testing, and care in 2018. (18) In the same fact sheet, the current top STDs in the United States include the following: 

• HPV
• HSV-2
• Trichomoniasis 
• Chlamydia
• Gonorrhea
• HIV
• HBV
• Syphilis

As per a U.S. News report analyzing STD statistics from 2022, the overall spread of sexually transmitted diseases had decreased from the previous year by 1.5%. (19) In the same report, the top 10 states with the highest STD rates included: 

1. Mississippi
2. Louisiana
3. South Dakota
4. Alaska
5. Georgia
6. South Carolina
7. Alabama
8. North Carolina
9. Arkansas
10. Arizona

• Practice Safe Sex: Use condoms consistently and correctly during all sexual encounters. 
• Carry Condoms: Ensure the availability of condoms by carrying them with you.
• Limit Partnerships: Restrict the number of sexual partners and avoid risky sexual behavior.
• Pre-Travel Testing: Get tested for STIs before traveling, especially if you anticipate sexual activity.
• Open Communication: Discuss STI prevention and testing openly with potential partners.
• Avoid Substance Abuse: With how alcohol and many drugs affect a person’s judgment, its best to avoid them when a sexual interaction is possible.
• Know Local Resources: Familiarize yourself with local healthcare and STD testing options.
• Prompt Medical Attention: Seek medical help if experiencing STD symptoms or concerns.
• Consider PrEP and PEP: Discuss HIV prevention options, like PrEP, with a healthcare provider before travel.
• Get Tested for STDs Weeks After Returning: To best match the window period per each STD, it's best to get tested two to three weeks after returning, except for cases of HIV and syphilis. HIV should be tested for 90 days after a potential interaction, and syphilis should be tested 90 days after a potential interaction. 

When it comes to sex and traveling, there’s always a chance of catching an STD from someone you do not know and additionally a chance from someone you do who has multiple partners. That’s why if you do decide to have intercourse on a trip, make sure to practice safe sex and get tested regularly. Call-On-Doc offers not only treatment but also testing and forms of prevention for the most common sexually transmitted diseases but also options for testing as well through a discreet and easy-to-access process.

1. “Sexually Transmitted Infections | Travelers' Health | CDC.” CDC, https://wwwnc.cdc.gov/travel/page/std.
2. “Chlamydia infection - PAHO/WHO.” Pan American Health Organization, https://www.paho.org/en/topics/chlamydia-infection.
3. Althaus C, Low NP1-S5.02 Towards more robust estimates of the per sex act transmission probability of Chlamydia trachomatis Sexually Transmitted Infections 2011;87:A175.
4. “The Odds of Getting Gonorrhea - STDcenterNY.” STD Center NYC, https://stdcenterny.com/odds-getting-gonorrhea.html.
5. Fuzayloff, Slava. “Transmission rate for genital herpes: Odds and Statistics.” STD Center NYC, 6 May 2023, https://stdcenterny.com/odds-of-getting-herpes.html.
6. Wilton, James. “Risk of Exposure to HIV/AIDS.” Stanford Health Care, https://stanfordhealthcare.org/medical-conditions/sexual-and-reproductive-health/hiv-aids/causes/risk-of-exposure.html.
7. Malagón T, MacCosham A, Burchell AN, El-Zein M, Tellier PP, Coutlée F, Franco EL; HITCH Study Group. Sex- and Type-specific Genital Human Papillomavirus Transmission Rates Between Heterosexual Partners: A Bayesian Reanalysis of the HITCH Cohort. Epidemiology. 2021 May 1, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8012224/. 
8. Andersen, Berit et al. “Mycoplasma genitalium: prevalence and behavioural risk factors in the general population.” Sexually transmitted infections vol. 83,3 (2007), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2659104/. 
9. Mohtasham, Diba. “Syphilis cases surge in the U.S., CDC says.” NPR, 31 January 2024, https://www.npr.org/2024/01/31/1228195107/syphilis-cases-soar-in-us-cdc-says.
10. Schmidt, Rebecca et al. “Resurgence of Syphilis in the United States: An Assessment of Contributing Factors.” Infectious diseases vol. 12 1178633719883282. 16 Oct. 2019, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6798162/. 
11. “STD Facts - Trichomoniasis.” Centers for Disease Control and Prevention, https://www.cdc.gov/std/trichomonas/stdfact-trichomoniasis.htm.
12. Plasner, Scott, and Jessica A. Schumann. “Trichomoniasis - StatPearls.” NCBI, https://www.ncbi.nlm.nih.gov/books/NBK534826/.
13. Kozak, Karolina et al. “The neurobiology of impulsivity and substance use disorders: implications for treatment.” Annals of the New York Academy of Sciences vol. 1451,1 (2019), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6450787/. 
14. Llamosas-Falcón, Laura et al. “A systematic review on the impact of alcohol use on sexually transmitted infections.” International journal of alcohol and drug research vol. 11,1 (2023), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10270666/. 
15. Dean, Hazel. “Sexually Transmitted Infections: What Women Need to Know.” Office on Women's Health, 28 April 2014, https://www.womenshealth.gov/blog/sexually-transmitted-infections.
16. N, Wilson Chialepeh, and Sathiyasusuman A. “Associated Risk Factors of STIs and Multiple Sexual Relationships among Youths in Malawi.” PloS one vol. 10,8 e0134286. 6 Aug. 2015, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4527764/. 
17. Andrews, Michelle. “Young people at risk for STDs often don't get tested, study says.” PBS, 4 June 2016, https://www.pbs.org/newshour/health/young-people-at-risk-for-stds-often-dont-get-tested-study-says.
18. “Incidence, Prevalence, and Cost of Sexually Transmitted Infections in the United States | Fact Sheets | Newsroom | NCHHSTP | CDC.” Centers for Disease Control and Prevention, 16 March 2022, https://www.cdc.gov/nchhstp/newsroom/fact-sheets/std/STI-Incidence-Prevalence-Cost-Factsheet.html.
19. Johnson, Ross. “10 States With the Highest STD Rates | Healthiest Communities Health News | U.S. News.” USNews.com, 31 January 2024, https://www.usnews.com/news/health-news/slideshows/10-states-with-the-highest-std-rates.