STDs and HIV – CDC Fact Sheet
People who have STDs are more likely to get HIV, when compared to people who do not have STDs.
Basic Fact Sheet | Detailed Version
Detailed fact sheets are intended for physicians and individuals with specific questions about sexually transmitted diseases. Detailed fact sheets include specific testing and treatment recommendations as well as citations so the reader can research the topic more in depth.
STDs and HIV.
People who have an STD may be at an increased risk of getting HIV. One reason is the behaviors that put someone at risk for one infection (not using condoms, multiple partners, anonymous partners) often put them at risk for other infections. Also, because STD and HIV tend to be linked, when someone gets an STD it suggests they got it from someone who may be at risk for other STDs and HIV. Finally, a sore or inflammation from an STD may allow infection with HIV that would have been stopped by intact skin.
STDs can increase the risk of spreading HIV.
HIV-infected persons are more likely to shed HIV when they have urethritis or a genital ulcer.4, 5 When HIV-infected persons get another STD such as gonorrhea or syphilis, it suggests that they were having sex without using condoms. If so, they may have spread HIV to their partners.
Some STDs are more closely linked to HIV than others.
In the US, both syphilis and HIV are highly concentrated epidemics among men who have sex with men.6, 7 In 2017, MSM accounted for 79.6% of all primary and secondary syphilis cases among males in which sex of sex partner was known.8 In Florida, in 2010, among all persons diagnosed with infectious syphilis 42% were also HIV infected.9 Men who get syphilis are at very high risk of being diagnosed with HIV in the future; among HIV-uninfected men who got syphilis in Florida in 2003, 22% were newly diagnosed with HIV by 2011.2 HIV is more closely linked to gonorrhea than chlamydia (which is particularly common among young women).10 Herpes is also commonly associated with HIV; a meta-analysis found persons infected with HSV-2 are at 3-fold increased risk for acquiring HIV infection.11, 12
Some activities can put people at increased risk for both STDs and HIV.
- Having anal, vaginal, or oral sex without a condom;
- Having multiple sex partners;
- Having anonymous sex partners;
- Having sex while under the influence of drugs or alcohol can lower inhibitions and result in greater sexual risk taking.
Does treating STDs prevent HIV?
Not by itself. Given the close link between STD and HIV in many studies, it seems obvious that treating STDs should reduce the risk of HIV. However, studies that have lowered the risk of STD in communities have not necessarily lowered the risk of HIV. Risk of HIV was lowered in one community trial, but not in 3 others.
- In Mwanza (Tanzania), improved STD treatment lowered 2-year HIV incidence by 40% in the intervention towns (1.2%) compared to other towns (1.9%).13
- In Rakai (Uganda), a more intensive intervention (mass treatment and improved STD control) was done, leading to lower rates of syphilis and trichomoniasis, but the incidence of HIV was the same in intervention and comparison towns (1.5% per year).14
- A third community trial found no difference in HIV incidence when behavioral plus STD control interventions were compared to usual services (Incidence rate ratio = 1.00), despite lower rates of syphilis (rate ratio 0.52) and gonorrhea (rate ratio 0.25).15
- A fourth community trial found HIV incidence was slightly higher in communities that received a combination of interventions including improved STD treatment when compared to control communities (incidence rate ratio 1.27, not statistically significant).16
Treating individuals for STDs has also not necessarily lowered their risk of acquiring HIV.
- One study found there was slightly lower risk of HIV seroconversion among female sex workers who had monthly exams for STD (5.3%) compared to sex workers who were examined when they had symptoms (7.6%, P=0.5); their rates of infection were lower for trichomonas (14% vs 7% P=0.07) but not for gonorrhea, chlamydia, or genital ulcers.17
- A second trial in female sex workers found a slightly higher incidence of HIV among women who received monthly treatment with azithromycin (4%) compared to women who did not (3.2%, P=0.5) despite major differences in the incidence of infection with gonorrhea (relative risk RR 0.46), chlamydia (RR 0.38), and trichomoniasis (RR 0.56).18
Three placebo-controlled trials have assessed the benefit to individuals from treatment with acyclovir to suppress genital herpes ulcers:
- One enrolled female sex workers who were infected with HSV but not HIV; it found no impact on HIV incidence in the acyclovir group (4.29%) compared to the placebo group (4.25%), though it also found no difference in reported episodes of genital ulceration or in measured HSV shedding.19
- A second study of HIV acquisition among persons infected with HSV-2 included women and men who have sex with men; HIV incidence was similar in the acyclovir group (3.9%) and the placebo group (3.3%) despite a 47% reduction in observed genital ulcers in the acyclovir group.20
- The third study looked at the effect of acyclovir on HIV transmission from heterosexuals infected with both HIV and HSV-2 to their HIV-uninfected partners; after removing 29% of new infections that were apparently acquired from an outside partner, the incidence was similar in the acyclovir group (1.8%) and the placebo group (1.9%, P=0.69) despite major reductions in genital ulcer disease (risk ratio 0.39).21
Screening for STDs can help assess a person’s risk for getting HIV. Treatment of STDs is important to prevent the complications of those infections, and to prevent transmission to partners, but it should not be expected to prevent spread of HIV.
What can people do to reduce their risk of getting STDs and HIV?
The only way to avoid STDs is to not have vaginal, anal, or oral sex. If people are sexually active, they can do the following things to lower their chances of getting STDs and HIV:
- Choose less risky sexual behaviors;
- Use condoms consistently and correctly;
- Reduce the number of people with whom they have sex;
- Limit or eliminate drug and alcohol use before and during sex;
- Have an honest and open talk with their healthcare provider and ask whether they should be tested for STDs and HIV.
- Talk with their healthcare provider and find out if pre-exposure prophylaxis, or PrEP, is a good option for them to prevent HIV infection.
If someone already has HIV, and subsequently gets an STD, does that put their sex partner(s) at an increased risk for getting HIV?
It can. HIV-negative sex partners are at greater risk of getting HIV from someone who is HIV-positive and acquires another STD. The HIV-negative sex partners of persons who are HIV-positive are less likely to get HIV if:
- HIV-positive persons use antiretroviral therapy (ART). ART reduces the amount of virus (viral load) in blood and body fluids. ART can keep HIV-positive persons healthy for many years, and greatly reduce the chance of transmitting HIV to sex partners if taken consistently.
- Sex partners take pre-exposure prophylaxis (PrEP) after discussing this option with his/her healthcare provider and determining whether it is appropriate.
- Choose less risky sexual behaviors.
- Use condoms consistently and correctly.
Will treating someone for STDs prevent them from getting HIV?
No. It’s not enough. Screening for STDs can help assess a person’s risk for getting HIV. Treatment of STDs is important to prevent the complications of those infections, and to prevent transmission to partners, but it should not be expected to prevent spread of HIV.
If someone HIV-positive is diagnosed with an STD, they should receive counseling about risk reduction and how to protect their sex partner(s) from getting re-infected with the same STD or getting HIV.
Health care providers with STD consultation requests can contact the STD Clinical Consultation Network (STDCCN). This service is provided by the National Network of STD Clinical Prevention Training Centers and operates five days a week. STDCCN is convenient, simple, and free to health care providers and clinicians. More information is available at www.stdccn.orgExternal.
Where can I get more information?
Sexually Transmitted Diseases – Home Page
HIV/AIDS and STDs – Topic Page
CDC-INFO Contact Center
TTY: (888) 232-6348
CDC National Prevention Information Network (NPIN)
P.O. Box 6003
Rockville, MD 20849-6003
American Sexual Health Association (ASHA)External
P. O. Box 13827
Research Triangle Park, NC 27709-3827
3. Pathela P, Braunstein SL, Blank S, Schillinger JA. HIV incidence among men with and those without sexually transmitted rectal infections: estimates from matching against an HIV case registry. Clin Infect Dis 2013;57:1203-1209.
4. Cohen MS, Hoffman IF, Royce RA, et al. Reduction of concentration of HIV-1 in semen after treatment of urethritis: implications for prevention of sexual transmission of HIV-1. Lancet 1997;349:1868-1873.
6. Pathela P, Braunstein SL, Schillinger JA, Shepard C, Sweeney M, Blank S. Men who have sex with men have a 140-fold higher risk for newly diagnosed HIV and syphilis compared with heterosexual men in New York City. J Acquir Immune Defic Syndr 2011;58:408-416.
8. Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance, 2017. Atlanta, GA: Department of Health and Human Services; September 2018.
9. Florida trends and statistics. Available at: http://www.doh.state.fl.us/disease_ctrl/std/trends/florida.htmlExternal accessed 9/2/13
10. Peterman TA, Newman DR, Maddox L, Schmitt K, Shiver S. Risk for HIV following a diagnosis of syphilis, gonorrhoea or chlamydia: 328,456 women in Florida, 2000–2011. Int J STD AIDS 2014; published online 8 April DOI: 10.1177/0956462414531243
12. Freeman EE, Weiss HA, Glynn JR, Cross PL, Whitworth JA, Hayes RJ. Herpes simplex virus 2 infection increases HIV acquisition in men and women: systematic review and meta-analysis of longitudinal studies. AIDS 2006;20:73-83.
15. Kamali A, Quigley M, Nakiyingi J, et al. Syndromic management of sexually-transmitted infections and behavior change interventions on transmission of HIV-1 in rural Uganda: a community randomized trial. Lancet 2003;361:645-652.
16. Gregson S, Adamson S, Papaya S, et al. Impact and process evaluation of integrated community and clinic-based HIV-1 control: a cluster-randomised trial in eastern Zimbabwe. PLoS Medicine 2007;4:e102.
18. Kaul R, Kimani J, Nagelkerke NJ, et al. Monthly antibiotic chemoprophylaxis and incidence of sexually transmitted infections and HIV-1 infection in Kenyan sex workers: a randomized controlled trial. JAMA 2004;291:2555-2562.
20. Celum C, Wald A, Hughes J, et al. Effect of acyclovir on HIV-1 acquisition in herpes simplex virus 2 seropositive women and men who have sex with men: a randomized, double-blind, placebo-controlled trial. Lancet 2008;371:2109-2119.