PrEP、保險套使用和性傳播疾病之間的關係是什麼？
資料來源：2019年7月17日；aidsmap news；財團法人台灣紅絲帶基金會編譯
愛滋病專家和專業人士一致認為，暴露前預防（PrEP）是愛滋病預防的一個有價值的補充，但根據上個月發表於健康與疾病社會學的一項研究，對於PrEP、減少保險套使用和性傳播感染（STI）之間的關係則有不同看法。
澳洲新南威爾斯大學的Martin Holt教授及其同事仔細研究了減少保險套使用和STI「被構建為政策問題」的方法。他們指出了一個「令人擔憂和震驚的觀點」，一個「中立和正常的立場」，以及一個「樂觀和批評的立場」等三種不同態度。
這三位作者說：「所有這三種立場都有選擇性地表現其證據，強調某些因素，忽視或淡化其他因素」。
2017年在澳大利亞對21名專業人士進行了訪談。其中有9名參與者是從事政策或政策/倡導工作，5名是從事臨床工作，5名是從事研究工作，2名是從事健康促進工作。
臨床醫生或政府政策制定者經常表達出擔憂和驚慌的觀點 – 鼓勵專業的團體預測風險以盡量減少風險。這些受訪者傾向於認為PrEP和STI之間的關聯是不言而喻的：「證據就在那裡，我們的臨床醫生告訴我們，我們需要做好準備，我們將增加性傳播感染。我們非常關心我們有一個，我們，你知道梅毒爆發流行了嗎？我們非常關注抗生素耐藥性淋病，我國對淋病的抗生素耐藥率最高。是啊。所以這些都是，是的，作為引入PrEP的後果或副產品，我們已經意識到這一點，所以我們需要注意回應這一點」。對不受控制或無法治癒的性傳播感染流行的恐懼以及對公共健康的潛在威脅，是這一觀點的基礎。就如同耐藥性淋病，受訪者還談到了未經確診的梅毒和其他不尋常病例的嚴重併發症。
Holt及其同事指出，雖然我們確實知道PrEP使用者不經常使用保險套並且高比率的被診斷為STI，但在澳大利亞和PrEP使用者當中抗生素耐藥性之情形是很少的。
相較之下，另有許多參與者表達了更溫和的觀點，經常質疑PrEP與減少使用保險套和增加性傳播感染明顯的關聯，而這些中立和正常化的認定涉及大量相同的證據，但亦將這些影響定位為可預測和可控制的。受訪者經常描述長期趨勢：「在PrEP到來之前，我們還看到了長達十多年的性傳播感染成長趨勢，以及圍繞保險套使用可能長達十多年下降的趨勢。因此PrEP在這個時刻可能正好表現像促進劑…… 但我沒有擔心。這是另一個新來到的工具，這是關於我們如何有效地將其整合納入我們的預防反應中」。這些受訪者表示，PrEP的好處超過了任一風險。他們強調PrEP的主要目的是預防愛滋病毒，但有時補充說，它還有其他好處：「當然，其中一個主要問題是，其他性傳播感染會出現大幅飆升，因為人們確實會停止使用保險套，我知道，在某些地區我們肯定會有保險套的使用輕微的、輕微的下降，但這是，這總是將會發生的。而且有時候總會有些人決定不或選擇不使用保險套。而現實情況是，他們更多地參與了他們所信任的健康服務，因此任何可能傳播的性傳播疾病無論如何都會被提前偵測到」。
然而，Holt評論說，保險套使用的變化是否「輕微」是值得商榷的。他自己的研究已經發現澳大利亞同性戀和雙性戀男性的性行為發生了大規模的變化。
第三和最後的立場被描述為樂觀的和批判的。表達這些想法的人傾向於針對PrEP對性傳播感染的益處持樂觀態度，並批評第一組受訪者的「性消極」和「保守的」觀點。這些受訪者最常是在社區組織或學術研究中工作。他們的樂觀主義基於以下信念：PrEP將促進對性傳播感染的定期篩檢：「我想很多人都會明白，實際上有大量愛滋病毒陰性的同性戀男性可以定期地接受檢測，這實際上是一件非常好的事情，實際上很難以其他方式實現。因此PrEP具有這種積極作用…… CDC對於此點有一些有趣的建模，這可能是一種情況就是二級預防的效果足以降低性傳播感染的發生率」。
然而，作者評論說，這些樂觀情景和數學模型研究是一個未經證實的未來。 正如之前描述的「最壞情況」之情景，實際上並未發生一樣，在PrEP使用者或已接受PrEP的社區中這些「最佳情況」之情景，亦未被觀察到。於此同時，PrEP已經從成為愛滋病預防技術轉變成為同時兼具提高STI測試兩種功能的技術。
同樣的受訪者傾向於批評所謂的「對增加性傳播感染的瘋狂恐懼」。他們指出，這種擔憂往往集中在男同性戀者而不是任何其他群體，並指出它與自愛滋病開始流行以來對男同性戀者的性行為進行審查方式的相似之處。
受訪者表示，男性之間的性行為已經「病態化」。雖然PrEP有可能減輕男同性戀者對愛滋病的持續恐懼，但這已經激發了一種退回：「我認為這也是你會聽到這些爭論的部分原因，你知道，「有關性傳染病將會怎麼樣？」或「每個人都將會成為『賤人』」。在那幾十年的病態化過程中，這種揮之不去的影響，我真的不認為可以被低估」。
代表意涵
研究人員表示，了解這些關係運作的方式對未來PrEP的推出及其使用者的體驗有影響。
令人擔憂和震驚的態度表明PrEP存在著問題。這意味著在推廣PrEP方面需要更加謹慎， PrEP的使用者應該被鼓勵去使用保險套，並且PrEP可能更佳地應定位為適合那些不能使用保險套者使用之工具。此外，應謹慎監測和處理PrEP使用者的行為。
中立和正常化的立場表明了一種「觀望」的態度，支持持續的、合標準的推出PrEP。由於PrEP主要是被視為愛滋病毒的預防工具，保險套和性傳播感染的趨勢則應該是相當程度予以區分。
樂觀和批評的立場意味著應該更積極地去促進PrEP，以幫助處理愛滋病毒和性傳染病之流行。它還建議PrEP的積極架構應該被用於鼓勵攝取，並包括慶祝PrEP使用者所經歷的緩解和愉悅。
What’s the relationship between PrEP, condom use and STIs? 17 July 2019
HIV experts and professionals agree that pre-exposure prophylaxis (PrEP) is a valuable addition to HIV prevention, but have varied views of the relationship between PrEP, reduced condom use and sexually transmitted infections (STIs), according to a study published last month in the Sociology of Health & Illness.
Professor Martin Holt of the University of New South Wales and colleagues closely examined the ways in which reduced condom use and STIs “were constructed as policy problems”. They identified a concerned and alarmed perspective, a neutral and normalising stance, and an optimistic and critical position.
“All three stances were selective in the way they performed evidence, emphasising some elements and ignoring or downplaying others,” the authors say.
Twenty one Australian professionals were interviewed in 2017. Nine of the participants worked in policy or policy/advocacy roles, five in clinical roles, five in research and two in health promotion.
Concerned and alarmed views were most often expressed by clinicians or by government policymakers – a professional group who are encouraged to anticipate risks in order to minimise them. These interviewees tended to see the link between PrEP and STIs as self-evident:
“The evidence is there and our clinicians are telling us we need to be prepared that we’re going to get an increase in STIs. We’re very concerned we’ve got a, we, you’re aware of the syphilis outbreak? We’re very concerned about antibiotic-resistant gonorrhoea. We have the highest rate of antibiotic resistance for gonorrhoea in the country. Yeah. So these are, yeah, these are quite, you know, we’re aware of this, as a consequence or by-product of introducing PrEP, so we need to be mindful of responding to that.”
The fear of uncontrolled or untreatable STI epidemics and the potential threat to public health underpinned this viewpoint. As well as resistant gonorrhoea, interviewees talked about serious complications of undiagnosed syphilis and other unusual cases.
Holt and colleagues point out that while we do know that PrEP users use condoms infrequently and are diagnosed with STIs at high rates, antibiotic resistance is rare in Australia and among PrEP users.
In contrast, many participants expressed more tempered views, often questioning the self-evident linking of PrEP, reduced condom use and increased STIs. These neutral and normalizing accounts engaged with much of the same evidence, but positioned these effects as predictable and manageable. Interviewees often described longer-term trends:
“We’ve also seen a decade-long, trend increase in STIs prior to PrEP’s arrival as well as probably a decade-long trend down around condom use. So PrEP is acting maybe as an accelerant at this moment in time … I don’t have concerns. It’s another tool that’s arrived and it’s about how we effectively incorporate it within our prevention response.”
These interviewees said the benefits of PrEP outweighed any risks. They emphasised that PrEP’s main purpose was to prevent HIV, but sometimed added that it has other benefits:
“Of course, one of the primary concerns was that there’d be this massive spike in other STIs because people would stop using condoms where certainly we’re, you know, in some areas there seems to be a slight, a slight decrease in condom use but that’s, that was always gonna happen. And there are people that will sometimes, you know, decide not to or choose not to use condoms anyway. And the reality is that they’re more engaged with a health service that they trust and so any STIs that might be transmitted are getting picked up earlier anyway.”
However, Holt comments that it is debatable whether changes in condom use are ‘slight’. His own research has identified large-scale shifts in sexual practices among gay and bisexual men in Australia.
The third and final stance is described as optimistic and critical. People expressing these ideas tended to be both optimistic about PrEP’s benefits for STIs and critical of the ‘sex negative’ and ‘reactionary’ views of the first group of interviewees. These respondents most often worked in community organisations or in academic research. Their optimism was based on beliefs that PrEP would facilitate regular screening for STIs:
“I think a lot of people will understand that actually having large numbers of HIV-negative, gay men who can be regularly tested is actually a really good thing that’s actually quite difficult to achieve in other ways. So PrEP has that positive effect… There’s some interesting modelling out of the CDC on this, it might be the case that the effect of secondary prevention is enough that it will drive down incidence of STIs.”
However the authors comment that these optimistic scenarios and mathematical modelling studies are an unproven future. Just as the ‘worst case’ scenarios described earlier have not actually happened, these ‘best case’ scenarios have not been observed among PrEP users or in communities that have embraced PrEP. At the same time, PrEP has been transformed from being an HIV prevention technology into being both that and a technology to increase STI testing.
The same respondents tended to be critical of what one described as a “frenzied fear about increased STIs”. They noted that such concerns tend to focus on gay men rather than any other group, noting parallels with the ways in which the sexual behaviour of gay men has been scrutinised since the beginning of the HIV epidemic.
Interviewees said that sex between men has been ‘pathologised’. While PrEP has the potential to relieve gay men of a persistent fear of HIV, this has inspired a push back:
“I think that’s partly why you also hear these arguments about, you know, ‘What about STIs?’ or ‘Everyone’s gonna be a ‘slut’’. It’s sort of the lingering effects of that, of those decades of pathologisation, which I really don’t think can be underestimated.”
Implications
The researchers say that the ways in which these relationships are understood have implications for the future rollout of PrEP and the experience of its users.
The concerned and alarmed approach suggests that PrEP is problematic. This implies greater caution in promoting PrEP, that PrEP users should be encouraged to use condoms and that PrEP might be better positioned as a niche tool for those who can’t use condoms. Moreover, the behaviour of PrEP users should be monitored and treated with caution.
The neutral and normalising stance suggests a ‘wait and see’ approach that supports the continued, measured rollout of PrEP. As PrEP is primarily seen as an HIV prevention tool, condom and STI trends should be considerably separately.
The optimistic and critical stance implies that PrEP should be promoted more enthusiastically to help with HIV and STI epidemics. It also suggests that positive framings of PrEP should be used to encourage uptake, including celebrating the relief and pleasure experienced by people using PrEP.
References
Holt M et al. HIV pre‐exposure prophylaxis and the ‘problems’ of reduced condom use and sexually transmitted infections in Australia: a critical analysis from an evidence‐making intervention perspective. Sociology of Health & Illness, early view, 18 June 2019. (Abstract).