翻譯人員: Alice Choy
研究顯示doxyPEP對預防性病具長期效果
越來越多的研究證實，性行為後服用強力黴素doxycycline（稱為doxyPEP）能降低性傳播感染 (Sexually Transmitted Infection, STI）的風險。最近在2025年逆轉錄病毒與機會性感染會議（CROI 2025）上，有兩項研究探討了在舊金山這個首個推行doxyPEP的城市中，長期使用doxyPEP的效果。
doxycycline暴露後預防措施（doxyPEP）包括在性行為後72小時內服用一劑200毫克的強力黴素。2022年國際愛滋病大會首次公布的DoxyPEP試驗結果顯示，doxyPEP可以降低男同志及跨性別女性中的HIV感染者或正在服用暴露前預防（PrEP）藥物，感染衣原體和梅毒的風險。結果顯示，對於淋病的風險也有較小但仍顯著的下降。然而，2023年報告的dPEP肯尼亞試驗發現，這一方法對非洲順性別女性的效果不佳。
這兩項新的研究分析了舊金山愛滋病基金會旗下Magnet性健康診所的doxyPEP實施情況，該診所主要服務同性戀、雙性戀和性別多元人群。
2022年10月，舊金山成為首個推薦使用doxyPEP的城市。根據去年CROI會議和《JAMA內科醫學》報導，儘管預防性使用doxycycline對淋病的影響較小，但似乎有助於該城市衣原體和梅毒發病率下降50%。
doxyPEP與性病發病率
舊金山愛滋病基金會的醫學主任Hyman Scott博士及其同事評估了doxyPEP對性病發病率的影響，並進行了為期兩年的研究。他之前曾在2024年CROI會議上報告過一年的數據。
Magnet性健康診所於2022年11月開始推廣doxyPEP，向所有接受HIV PrEP或其他性健康服務的客戶推廣doxyPEP。doxyPEP接受度頗高，初期doxyPEP需求和使用率都很高。
本次分析納入了截至2024年9月為止的2,524名接受服用doxyPEP處方的人—這個數字是去年報告的兩倍—以及2,068名未服用者。對於服用者，研究人員收集了最多五個季度的處方前後的數據。對於未服用者，分析了2023年4月前後的數據。
使用者中約90%為順性別男性，約10%為跨性別或非二元性別者，中位年齡為35歲。大約三分之一為白人，24%為拉美裔，16%為亞裔，13%為多種族，4%為黑人。（相比之下，舊金山的人口約38%為非西班牙裔白人，37%為亞裔，16%為拉美裔，6%為黑人。）兩組的基本人口特徵相似，超過90%的使用者有服用HIV PrEP，主要是每日口服藥物。
在開始服用doxyPEP之前，使用者感染性病風險是非使用者的近四倍。在服用doxyPEP開始前，服用者的性病發病率急劇上升，而未服用者的發病率則在下降。在服用doxyPEP開始後，服用者的性病發病率大幅下降，而未使用者則呈現持續緩慢下降，因此兩組之間的差距縮小。
服用doxyPEP者，梅毒下降了89%、衣原體下降了81%、淋病下降了44%。這三項下降均具有統計學意義，並且在後續追蹤期間保持穩定。Scott博士指出，這是首個顯示淋病下降近50%的現實世界數據，與DoxyPEP試驗結果一致。
研究人員總結道，「doxyPEP的服用持續增加，且服用doxyPEP者的細菌性性病發病率整體顯著下降，包括淋病在內，顯示doxyPEP在現實世界中的持續高效。」這些發現表明，那些最能從doxyPEP中受益的人正在選擇這項措施，Scott博士補充道。
當被問及為何此研究顯示doxyPEP對淋病的效果優於其他研究時，Scott博士認為，長期追蹤可能起到了關鍵作用。此外，儘管doxyPEP指南指出可在性行為後最多72小時內服用doxycycline，Magnet性健康診所建議客戶在24小時內服用——作為“當晚最後一次的活動”，這樣能更有效。
doxyPEP的照護連續性
在第二項研究中，Michael Barry博士(公共衛生碩士)及其同事，分析了舊金山愛滋病基金會在Magnet性健康診所提供的doxyPEP照護連續性，該診所的客戶符合舊金山公共衛生部門的doxyPEP使用指導方針，並在2022年12月到2024年12月期間至少有兩次就診。
在7,436名符合的人群中，59%收到了處方，根據其醫療記錄顯示。其中61%（即總體符合資格的36%）報告表示曾服用至少一劑doxycycline。這些人中有61%（即符合資格者的22%）報告表示有高服用持續性，即每次性行為後72小時內持續使用。
研究人員注意到，照護連續性中存在一些顯著的群體差異。在符合人群中，36到44歲的人比14到29歲的人更有可能接受處方（64%對53%）。跨性別女性最有可能被處方doxyPEP（69%），而跨性別男性最不可能（39%）。有穩定住房的人群中有60%接受處方，而無家可歸或住房不穩定者為48%。 HIV陰性且服用PrEP的人比未服用PrEP或HIV感染者更有可能接受doxyPEP（分別為71%、44%和56%）。
在接受doxyPEP處方的人中，36到44歲的群體比年輕群體（66%對57%）更有可能至少服用一次。白人更有可能開始服用doxyPEP，相比之下黑人較少（63%對55%）；有穩定住房的人比無穩定住房的人更有可能服用（62%對47%）；非HIV患者且服用PrEP的人比HIV感染者更有可能服用（62%對50%）。
在至少服用了doxycycline一次的群體中，45歲及以上的人群維持高服用持續性的可能性較年輕群體高（68%對58%）；非HIV患者且服用PrEP的人也比HIV感染者有較高的服用持續性（63%對50%）。
Barry博士指出，儘管使用者的服用持續性相對較低，但Scott報告的性病顯著下降，仍顯示出“doxyPEP在整體人群中的影響”。他表示：“我們看到了因為doxyPEP的使用，對整體人群產生的影響，但若服用持續性更高，效果可能會更好。”
會後，研究人員討論了如何正確定義doxyPEP的良好服用持續性，因為並非所有性行為都需要使用此藥物。例如，有些人可能在性派對後服用doxyPEP，但在與固定伴侶的性行為後則不服用。
Barry博士在會議中簡報時表示：「我認為我們的患者非常聰明，能夠知道哪些伴侶、哪些情況或哪些性行為會受益於使用這種藥物。」
Studies Show Longer-Term Benefits of doxyPEP for STI Prevention
San Francisco clinic sees significant drop in sexually transmitted infections despite quite low adherence to doxycycline prophylaxis over time.
March 24, 2025 • By Liz Highleyman
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A growing body of research confirms that taking the antibiotic doxycycline after sex—an approach known as doxyPEP—reduces the risk of sexually transmitted infections (STIs). Two studies presented at the recent Conference on Retroviruses and Opportunistic Infections (CROI 2025) looked at longer-term doxyPEP use in San Francisco, the city that rolled it out first.
Doxycycline post-exposure prophylaxis involves taking a single 200 milligram dose of the antibiotic within 72 hours after sex. Results from the DoxyPEP trial, first presented at the 2022 International AIDS Conference, showed that it lowered the risk for chlamydia and syphilis among gay men and transgender women who were either living with HIV or on pre-exposure prophylaxis (PrEP); results showed a smaller but still significant decline in the risk for gonorrhea. However, the dPEP Kenya trial, reported the following year, found that this approach did not work well for cisgender women in Africa.
The two new studies looked at doxyPEP implementation at the San Francisco AIDS Foundation’s Magnet sexual health clinic in the Castro neighborhood, which primarily serves gay and bisexual men and gender-diverse people.
In October 2022, San Francisco was the first city to recommend doxyPEP. As reported at last year’s CROI and in JAMA Internal Medicine, prophylactic doxycycline appears to have contributed to a 50% decline in chlamydia and syphilis citywide, though there was little effect on gonorrhea.
DoxyPEP and STI Rates
Hyman Scott, MD, MPH, medical director at the San Francisco AIDS Foundation, and colleagues evaluated the sustained impact of doxyPEP on STI incidence over a two-year period. He previously reported one-year data at CROI 2024.
Magnet began rolling out doxyPEP in November 2022, offering it to all clients who received HIV PrEP or other sexual health services at the clinic. The reception was enthusiastic, and initial doxyPEP demand and uptake were high.
This analysis included 2,524 people who were prescribed doxyPEP at any time through September 2024—about double the number in last year’s report—along with 2,068 nonusers. For users, the researchers included data from up to five quarters before and after the initial prescription; for nonusers, they looked at data for up to five quarters before and after April 2023.
About 90% were cisgender men, about 10% were transgender or nonbinary and the median age was 35 years. About a third were white, 24% were Latino, 16% were Asian, 13% were multiracial and 4% were Black. (For comparison, San Francisco’s population is approximately 38% non-Hispanic white, 37% Asian, 16% Latino and 6% Black.) Demographic characteristics were similar between the two groups. More than 90% were on HIV PrEP, mostly daily pills.
Before starting doxyPEP, users had nearly a fourfold higher risk of STIs compared with nonusers. In the pre-doxyPEP period, STIs were rising steeply among users and falling among nonusers. In the post-doxyPEP period, there was a substantial drop in STIs among doxyPEP users while nonusers saw an ongoing shallow decline, so the difference between the two groups diminished.
Among doxyPEP users, syphilis declined by 89%, chlamydia by 81% and gonorrhea by 44%. All three reductions were statistically significant and sustained throughout the follow-up period. Scott noted that this is the first real-world data showing a nearly 50% decline in gonorrhea, in line with the DoxyPEP trial.
“DoxyPEP uptake continues to increase, and bacterial STI incidence among doxyPEP users declined significantly overall and for each STI, including gonorrhea, demonstrating sustained high impact of this intervention in a real-world setting,” the researchers concluded. These findings indicate that those who could benefit most from doxyPEP are choosing it, according to Scott.
Asked why this study showed better efficacy against gonorrhea than others, Scott suggested that longer follow-up may play a role. In addition, although doxyPEP guidelines say doxycycline can be taken up to 72 hours after sex, Magnet advises that clients take it within 24 hours—as the “last load of the night”—when it’s more likely to be effective.
DoxyPEP Care Continuum
In the second study, Michael Barry, PhD, MPH, and colleagues at the SF AIDS Foundation looked at the doxyPEP continuum of care among Magnet clients who were eligible for doxycycline prophylaxis according to San Francisco Department of Public Health guidelines and had at least two visits between December 2022 and December 2024.
Among the 7,436 clients with a doxyPEP indication, 59% received a prescription, according to their medical records. Of these, 61% (or 36% of the total eligible group) reported taking at least one dose of doxycycline. Of those, 61% (or 22% of the eligible group) reported high adherence, defined as consistent use within 72 hours after sex since their last visit.
The researchers saw some notable demographic differences across the continuum. Among people eligible for doxyPEP, those between ages 36 and 44 were more likely to receive a prescription than those ages 14 to 29 (64% versus 53%). Transgender women were most likely to be prescribed doxyPEP (69%) and trans men the least likely (39%). While 60% of people with stable housing were prescribed doxyPEP, this fell to 48% for those who were unstably housed or homeless. HIV-negative PrEP users were more likely to receive doxyPEP than the smaller groups of HIV-negative people not on PrEP or HIV-positive people (71%, 44% and 56%, respectively).
Among those prescribed doxyPEP, the 36–44 age group was more likely to take it at least once compared with younger people (66% versus 57%). White people were more likely to start doxyPEP compared with Black people (63% versus 55%), stably housed people were more likely to do so than those without stable housing (62% versus 47%), and HIV-negative people on PrEP were more likely to do so than HIV-positive people (62% versus 50%).
Among those who took at least one dose of doxycycline, those ages 45 and older were more likely to maintain high adherence compared to the youngest group (68% versus 58%), as were HIV-negative PrEP users compared to HIV-positive people (63% versus 50%).
Looking at the total population with a doxyPEP indication, high adherence was less likely among young people (17%), Black people (19%), unstably housed or homeless people (13%) and people living with HIV (14%).
Barry noted that the dramatic declines in STIs reported by Scott occurred despite “somewhat low adherence” to doxyPEP over time. “We’re seeing population-level impacts very likely due to doxyPEP uptake, but it could be even higher,” he said. “To ensure equitable population-level impacts of doxyPEP, we might consider giving these patients special consideration.”
After the presentation, researchers in the audience discussed how best to define good adherence to doxyPEP, as it might not be needed for all sexual encounters. For example, someone might use doxyPEP after a sex party but not after sex with a regular partner.
“I think our patients are very savvy at knowing which partners or which situations or which encounters will benefit from using this medication,” Barry said at a conference news briefing.
Click here for a POZ feature on doxyPEP.
Click here for more news about STIs.
Click here for more reports from CROI 2025
雖然doxyPEP能降低性傳播感染的風險，但使用保險套仍是防治性病的主要方式。
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原文連結:
https://www.poz.com/article/studies-show-longerterm-benefits-doxypep-sti-prevention
