The Centers for Disease Control and Prevention's June 2024 clinical guideline says 200 mg of doxycycline taken within 72 hours after sex reduces chlamydia and syphilis infections by more than 70 percent and gonorrhea infections by approximately 50 percent, based on three large randomized trials. The pivotal US trial that drove the guideline enrolled 501 participants, 67 percent of whom were White and 7 percent of whom were Black (Luetkemeyer 2023, NEJM).
Two years after CDC published the guideline, the most recent peer-reviewed US uptake study of men who have sex with men with HIV (827 participants across 46 states, DC, and Puerto Rico) does not report a Black-MSM-specific awareness or uptake figure in its abstract. It does report that doxy-PEP awareness and uptake are significantly lower in the Midwest, Mountain, and South regions compared with the Pacific (Martinson 2025, AIDS). The South holds 56 percent of the US Black population as of 2023, per Pew Research Center analysis of Census American Community Survey data.
That is the Black-MSM doxy-PEP story so far. Trial-grade evidence is strong. Real-world implementation in San Francisco and Kaiser Permanente Northern California is strong. Black-MSM-specific access data, with verbatim race-stratified numbers from federal surveillance, the pivotal trial, or the mainstream uptake literature, is largely absent.
What CDC actually recommends
CDC's guideline is narrow. It applies to MSM and transgender women who have had a syphilis, chlamydia, or gonorrhea diagnosis in the past 12 months. "CDC recommends that MSM and TGW who have had a bacterial STI (specifically syphilis, chlamydia, or gonorrhea) diagnosed in the past 12 months should receive counseling that doxy PEP can be used as postexposure prophylaxis to prevent these infections," the guideline reads (Bachmann 2024, MMWR Recomm Rep). The dose is 200 mg of doxycycline within 72 hours after oral, vaginal, or anal sex, not to exceed 200 mg per 24 hours.
CDC does not recommend doxy-PEP for cisgender women. The only randomized trial in cisgender women, conducted in 449 Kenyan women aged 18 to 30 on HIV PrEP, showed no significant difference in incident STIs between the doxy-PEP and standard-care arms (relative risk 0.88, 95 percent confidence interval 0.60 to 1.29, P = 0.51). Two alternative explanations dominate: only 29 percent of hair samples from a random subset showed doxycycline detection, and all gonorrhea isolates in the trial were tetracycline-resistant (Stewart 2023, NEJM).
The guideline also requires that anyone prescribed doxy-PEP be tested for bacterial STIs at all anatomic sites of exposure at baseline and every 3 to 6 months thereafter (Bachmann 2024). Doxy-PEP is not a substitute for HIV PrEP, for condom use, or for routine STI screening. It is part of a sexual-health visit, not a stand-alone strategy.
What the trials show, and who they enrolled
The US trial that anchors CDC's recommendation is Luetkemeyer 2023, published in the New England Journal of Medicine. Researchers in San Francisco and Seattle enrolled 501 MSM and transgender women who had had gonorrhea, chlamydia, or syphilis in the year before enrollment. The HIV-negative PrEP cohort showed an absolute reduction of 21.2 percentage points in any quarterly STI (relative risk 0.34, 95 percent confidence interval 0.24 to 0.46, P less than 0.001). The HIV-positive cohort showed an 18.7 percentage-point reduction (relative risk 0.38, 95 percent confidence interval 0.24 to 0.60, P less than 0.001).
The trial reported its racial composition verbatim: "Of 501 participants (327 in the PrEP cohort and 174 in the PLWH cohort), 67% were White, 7% Black, 11% Asian or Pacific Islander, and 30% Hispanic or Latino." That is roughly 35 Black participants in a US-pivotal trial of a CDC-recommended prevention strategy. No race-stratified subgroup effect size was reported in the primary publication. The published evidence base does not yet answer whether the Luetkemeyer effect sizes hold across racial groups in the United States.
The gonorrhea result deserves its own caveat. In Luetkemeyer, 5 of 13 gonorrhea isolates in doxycycline arms were tetracycline-resistant, compared with 2 of 16 in standard-care arms. CDC's guideline framing of approximately 50 percent reduction in gonococcal infections reflects the meta-trial average. Real-world implementation in jurisdictions where tetracycline-resistant Neisseria gonorrhoeae is already common appears to weaken or reverse the gonorrhea benefit, which the next section quantifies.
Chlamydia and syphilis fall sharply, gonorrhea is the unresolved question
Two large 2025 studies in JAMA Internal Medicine tested doxy-PEP at population and cohort scale in California. Both confirm trial-grade chlamydia and syphilis reductions. Both confirm the gonorrhea caveat.
San Francisco's interrupted time-series analysis of all reported chlamydia, gonorrhea, and early syphilis cases among MSM and transgender women from July 2021 through November 2023 found a 49.6 percent reduction in chlamydia cases and a 51.4 percent reduction in early syphilis cases over the 13 months after the city's October 2022 doxy-PEP guideline release. Gonorrhea cases rose 1.77 percent per month relative to projection over the same window (95 percent confidence interval 0.87 to 2.67) (Sankaran 2025, JAMA Intern Med).
The Kaiser Permanente Northern California PrEP cohort, which included 11,551 PrEP users between November 2022 and December 2023, found that quarterly chlamydia positivity among doxy-PEP recipients dropped from 9.6 percent before starting doxy-PEP to 2.0 percent after, a 79 percent reduction. Gonorrhea positivity moved from 10.2 percent to 9.0 percent (relative risk 0.88, 95 percent confidence interval 0.77 to 1.00, P = 0.048), a modest decline driven by site-specific reductions at rectal and urethral sites (Traeger 2025, JAMA Intern Med).
Buried in the Traeger paper is an insurance-coverage signal worth pulling forward. Among doxy-PEP recipients, 92.8 percent had commercial insurance. Among non-recipients, 88.9 percent did. Both numbers are high because Kaiser is an integrated managed-care system, but the gap suggests that even inside a well-resourced system, the patients getting doxy-PEP skew toward commercial coverage rather than Medi-Cal. That is the first quantitative signal in the published US literature that doxy-PEP uptake tracks insurance type.
Where the Black-MSM access story sits
The Black-MSM specific story has four pieces, none of which fits cleanly inside the trial-and-surveillance evidence chain.
The first is the trial sample. Seven percent of Luetkemeyer 2023 enrollees were Black. No race-stratified Luetkemeyer subgroup effect size has been published. The Atlanta InvolveMENt cohort (562 HIV-negative MSM, 843 person-years of follow-up) documented that rectal bacterial STI was significantly associated with subsequent HIV acquisition in propensity-score-weighted adjusted analyses (adjusted hazard ratio 2.7, 95 percent confidence interval 1.2 to 6.4), with a population attributable fraction for rectal STI of 14.6 (95 percent confidence interval 6.8 to 31.4). The Atlanta cohort was racially stratified and explicitly designed to measure bacterial STI burden in Black MSM compared with White MSM (Kelley 2015, AIDS Res Hum Retroviruses). The population with the highest documented bacterial STI burden and the strongest STI-to-HIV-acquisition pathway is also the population whose subgroup effect size from the pivotal doxy-PEP trial has not been published.
The second is the geography of uptake. Martinson 2025 enrolled 827 US MSM with HIV across 46 states, DC, and Puerto Rico and found that doxy-PEP awareness and uptake were lower in the Midwest, Mountain, and South regions than in the Pacific (awareness inverse-variance weighted adjusted odds ratio 0.81, 95 percent confidence interval 0.76 to 0.86; uptake adjusted odds ratio 0.86, 95 percent confidence interval 0.82 to 0.90). Among the 360 participants who met CDC eligibility criteria, 20 percent were prescribed doxy-PEP, 49 percent had heard of it but were not on it, and 31 percent had not heard of it (and 95 percent of that 31 percent expressed interest after the survey explained it). Martinson does not report a Black-MSM-specific awareness or uptake number in the abstract. The South-region underperformance is the available proxy.
The third is the clinical setting where the Black-MSM uptake story is being measured. Us Helping Us, a Black-MSM-led community health organization in Washington DC, published a case-control study in Sexually Transmitted Infections examining predictors of doxy-PEP prescription receipt in its patient population (Ogunbajo 2024, Sex Transm Infect). Ade Ogunbajo, PhD, MPH, Director of Research at Us Helping Us, led the analysis. DeMarc Hickson, the organization's Executive Director, was last author. The letter format compresses the abstract; the full text is one of the only publicly available windows into Black-MSM doxy-PEP uptake inside a Black-MSM-serving clinic.
The fourth is structural-coverage. Most state Medicaid programs do not publish a doxy-PEP-specific coverage policy. The National Coalition of STD Directors maintains a sample-policies compendium (NCSD doxy-PEP sample policies, last updated July 2023) that catalogs more than a dozen state and local health-department guidance documents but does not specify Medicaid coverage status. The Black-MSM uninsured rate is roughly twice the White-MSM rate per KFF analysis of American Community Survey microdata. The Traeger 92.8 percent commercial-insurance signal lands in that context.
Naming what is absent is the accountability beat. The Black-MSM doxy-PEP access story is not visible in the trial data because the trial did not enroll a representative Black-MSM sample. It is not visible in the surveillance data because the 2024 CDC STI surveillance report is published as provisional national totals only, with race and ethnicity stratification deferred to the final 2024 publication (see CDC's STI surveillance index). It is partially visible in regional uptake data and inside one Black-MSM-led DC clinic. The published evidence base reflects what has been studied, not what is true on the ground.
What you can do
If you are a Black man who has sex with men, a transgender woman, or your sexual partner is, and you have had a syphilis, chlamydia, or gonorrhea diagnosis in the past 12 months, you meet CDC's 2024 doxy-PEP eligibility criteria. Three specific asks you can take to a sexual-health visit:
Ask your primary care clinician, an infectious-disease specialist, or a sexual-health clinic whether doxy-PEP is right for you, and ask them to walk through the CDC 2024 guideline language rather than their own paraphrase. The eligibility criteria are narrow and specific. Ask them to document the prescribing decision in your chart.
Ask whether your state Medicaid program covers doxycycline as post-exposure prophylaxis. If your state does not cover it for that indication, ask for the cash price of generic doxycycline 200 mg, which sits on the lower-tier generic price band at most US pharmacies; cash price varies by pharmacy chain, prescription discount, and supply duration. Ask whether the clinic has a sliding-scale program for the visit itself.
Ask the clinic about their bacterial STI testing cadence. CDC requires testing at all anatomic sites of exposure at baseline and every 3 to 6 months (Bachmann 2024). A clinic that prescribes doxy-PEP without committing to quarterly site-specific testing is not following the guideline.
You can search our provider directory for clinicians who specialize in sexual and reproductive health for Black communities. We list verified license and NPI for every provider on the site.
If you work in a state legislature, a state Medicaid office, a community health center, or a public-health department, the absence of a Black-MSM-specific doxy-PEP coverage and uptake tracker is one of the cheapest data investments available right now. A state-by-state coverage tracker, race-stratified uptake data from Medicaid claims, and a Black-MSM-led implementation study like the Us Helping Us case-control replicated in three to five other regions would close most of the data gap this article describes.
Citations
- Bachmann LH, Barbee LA, Chan P, Reno H, Workowski KA, Hoover K, Mermin J, Mena L. "CDC Clinical Guidelines on the Use of Doxycycline Postexposure Prophylaxis for Bacterial Sexually Transmitted Infection Prevention, United States, 2024." MMWR Recomm Rep. 2024 Jun 6;73(2):1-8. PMID 38833414. https://pubmed.ncbi.nlm.nih.gov/38833414/
- Luetkemeyer AF, Donnell D, Dombrowski JC, et al. "Postexposure Doxycycline to Prevent Bacterial Sexually Transmitted Infections." N Engl J Med. 2023 Apr 6;388(14):1296-1306. PMID 37018493. https://pubmed.ncbi.nlm.nih.gov/37018493/
- Stewart J, Oware K, Donnell D, et al. "Doxycycline Prophylaxis to Prevent Sexually Transmitted Infections in Women." N Engl J Med. 2023 Dec 21;389(25):2331-2340. PMID 38118022. https://pubmed.ncbi.nlm.nih.gov/38118022/
- Sankaran M, Glidden DV, Kohn RP, et al. "Doxycycline Postexposure Prophylaxis and Sexually Transmitted Infection Trends." JAMA Intern Med. 2025 Mar 1;185(3):266-272. PMID 39761052. https://pubmed.ncbi.nlm.nih.gov/39761052/
- Traeger MW, Leyden WA, Volk JE, et al. "Doxycycline Postexposure Prophylaxis and Bacterial Sexually Transmitted Infections Among Individuals Using HIV Preexposure Prophylaxis." JAMA Intern Med. 2025 Mar 1;185(3):273-281. PMID 39761062. https://pubmed.ncbi.nlm.nih.gov/39761062/
- Martinson T, Heise MJ, Sassaman K, et al. "Interest and disparities in awareness and uptake of doxycycline postexposure prophylaxis among US MSM with HIV." AIDS. 2025 Jul 15;39(9):1191-1196. PMID 40162974. https://pubmed.ncbi.nlm.nih.gov/40162974/
- Ogunbajo A, Henry C, Barney A, Anderson T, Brown J, Hickson D. "Predictors of receiving a doxycycline postexposure prophylaxis (Doxy-PEP) prescription for the prevention of bacterial sexually transmitted infections (STIs) in a community-based clinic: a case-control study." Sex Transm Infect. 2025 Jan 29;101(1):68-69. PMID 39256030. https://pubmed.ncbi.nlm.nih.gov/39256030/
- Kelley CF, Vaughan AS, Luisi N, et al. "The Effect of High Rates of Bacterial Sexually Transmitted Infections on HIV Incidence in a Cohort of Black and White Men Who Have Sex with Men in Atlanta, Georgia." AIDS Res Hum Retroviruses. 2015 Jun;31(6):587-592. PMID 25719950. https://pubmed.ncbi.nlm.nih.gov/25719950/
- CDC. "Sexually Transmitted Infections Surveillance, 2024 (Provisional)." Atlanta: US Department of Health and Human Services, CDC. https://www.cdc.gov/sti-statistics/annual/index.html
- National Coalition of STD Directors. "Doxy- and STI-PEP Sample Policies." https://www.ncsddc.org/resource/doxy-and-sti-pep-sample-policies/
- Pew Research Center. "Facts about the U.S. Black population." (Analysis of US Census Bureau American Community Survey data through 2023.) https://www.pewresearch.org/social-trends/fact-sheet/facts-about-the-us-black-population/
- KFF. "Key Data on Health and Health Care by Race and Ethnicity." https://www.kff.org/racial-equity-and-health-policy/issue-brief/key-data-on-health-and-health-care-by-race-and-ethnicity/
