全球分析發現，跨性別女性感染HIV的可能性是男性的66倍，而跨性別男性的可能性是近7倍

資料來源：Krishen Samuel / 2022 年 3 月 14 日/aidsmap news

The Gender Spectrum Collection. Images are for illustrative purposes only.

根據馬斯特里赫特大學的 Sarah Stutterheim 博士及其同事在PLOS ONE上發表的一項系統評價，更新的盛行率估計顯示，不僅跨性別女性比以前所認為的更容易感染HIV，而且跨性別男性的風險也比一般人口中的男性高得多。

跨性別者——尤其是跨性別女性——感染HIV的風險增加。包括跨性別恐懼症在內的結構性因素導致歧視、有限的工作機會、獲得醫療服務的機會減少、心理健康上的法律障礙和挑戰。這些因素會影響行為風險因素，包括接受性的無套肛交、性交易和共用針具進行荷爾蒙注射等。

雖然之前已建立的全球盛行率估計顯示，跨性別女性感染HIV的風險要高得多，但關於跨性別男性的數據很有限。目前尚不清楚跨性別男性感染HIV的風險實質上是否比一般成年人口高得多。許多先前的研究要麼將跨性別女性和男性的HIV盛行率結合起來，要麼便是將跨性別女性與男男性行為者 (MSM) 納在一起研究。

此外，根據如何測量 HIV 的存在之數字上存在著差異——無論是基於自我報告數據還是實驗室確認的檢測。也有人提出，跨性別女性盛行率估計值如此之高的一個可能原因是，許多研究人員嚴重依賴便利抽樣等方法，最終可能會對跨性別女性性工作者進行過度抽樣，從而誇大其盛行率。先前的研究也無法提供世界不同地區跨性別者其HIV盛行率的估計值。

研究

研究人員對 2000 年至 2019 年間發表的有關跨性別者HIV盛行率的所有研究進行了系統回顧和薈萃分析。它們包括來自 34 個國家的 98 項研究，以任何語言發表，包括實驗室確認的 HIV 盛行率。大多數研究（78 項）涉及跨性別女性，其中 4 項與跨性別男性相關，16 項與跨性別男性與女性兩者相關。總共包括來自 34 個國家的 48,604 名跨性別女性和來自六個國家（澳大利亞、巴西、加拿大、意大利、西班牙和美國）的 6,460 名跨性別男性。相對於僅僅匯總盛行率的方式，他們根據數據收集年份之國家層級 HIV 盛行率去計算標準化盛行率。這是在全球範圍內且針對不同地理區域進行的。研究人員還特別考慮了不同類型的抽樣所產生的盛行率估計之差異，以及美國 PrEP 前和 PrEP 後的盛行率估計值。

全球和區域性的HIV盛行率

在全球範圍內，跨性別女性的總體標準化 HIV 盛行率為 19.9%（95% 信賴區間 [CI] 14.7% – 25.1%），跨性別男性為 2.56%（95% CI 0.0% – 5.9%）。與普通人群中之 15 歲及以上人群的HIV盛行率相比，跨性別女性感染HIV的勝算比高達驚人的 66 倍，而跨性別男性則高達 6.8 倍。

對於跨性別女性，區域分析顯示，在撒哈拉以南非洲 1,192 人的樣本中，標準化 HIV 盛行率為 29.9%（95% CI 22.5% – 37.3%），感染比例是普通人群的 21.5 倍。在拉丁美洲，盛行率為 25.9%（95% CI 20.0% – 31.8%），在 7,917 人的樣本中其感染 HIV 的機率高達 95.6 倍。在亞洲，在 14,798 人的樣本中，HIV盛行率為 13.5%（95% CI 2.3% – 17.7%），機率高達 68 倍。最後，在澳大利亞、歐洲和北美，標準化 HIV 盛行率為 17.1%（95% CI 13.1% – 21.1%），在 24,697 人樣本中的勝算比為 48.4。

最常用的抽樣方法提供了相似範圍內的盛行率估計值。在 33 項研究中使用了基於關聯個體網絡的受訪者驅動抽樣，與最高的盛行率23.3% 相關（95% CI 18.0% – 28.4%）。當盛行率係基於性病 STI 診所的患者（用於 26 項研究）時，標準化盛行率較低，為 17.4%（95% CI 12.2% – 22.7%）。基於容易發現可觸及跨性別人群的便利抽樣——例如在專門的跨性別健康診所進行——得出的盛行率與跨性別女性的總體估計相似，為 19.7%（95% CI 14.8% – 24.5%）。

有趣的是，研究人員沒有發現在美國引入 PrEP 後盛行率降低的證據。事實上，跨性別女性的盛行率從 PrEP 前時期（1997 年至 2011 年）的 18.4%（95% CI 14.8% – 22.0%）增加到 2012 年至  2017 年期間的 23.7%（95% CI 20.2% – 27.2%）. 這可能與在引入 PrEP 後只有六項關於盛行率的研究有關，導致估計有所偏差。研究人員還指出，迄今為止，為跨性別女性提供的 PrEP 仍是有限的。

結論

「這項系統評價和薈萃分析證實，跨性別者受到不成比例的HIV影響，不僅跨性別女性個體如此，跨性別男性個體也是如此。在使用比以往任何時候都更大的匯總樣本，我們確認與 15 歲以上的其他人相比，跨性別男性感染 HIV 的可能性幾乎是其他人的 7 倍，而跨性別女性感染 HIV 的可能性是其他人的 66 倍」，作者總結道。 

「此外，基於來自主要地理區域的 34 個國家的數據，我們發現跨性別者有不成比例的HIV負擔是一種全球現象，並且在非洲和拉丁美洲等某些地區可能受到的影響更比別人多，這一論點得到了支持」。

Trans women 66 times more likely to have HIV, with trans men nearly 7 times more likely, global analysis finds

資料來源：Krishen Samuel / 14 March 2022/ aidsmap news

The Gender Spectrum Collection. Images are for illustrative purposes only.

Updated prevalence estimates based on a systematic review by Dr Sarah Stutterheim and colleagues at Maastricht University published in PLOS ONE show that not only are trans women much more likely to acquire HIV than previously thought, trans men are also at a substantially higher risk than the general population.

Transgender individuals – especially trans women – are at an increased risk of HIV infection. Structural factors, including transphobia, result in discrimination, limited work opportunities, reduced access to healthcare services, legal barriers and challenges with mental health. These factors influence behavioural risk factors, including condomless anal receptive sex, transactional sex, and sharing needles for hormone injections.

While previous global prevalence estimates established that trans women are at a dramatically higher risk of getting HIV, there are limited data on trans men. It has been unclear if trans men have a substantially higher risk of acquiring HIV than the general adult population. Many previous studies have either combined HIV prevalence for trans women and men, or have included trans women with men who have sex with men (MSM).

Additionally, there are discrepancies in figures based on how the presence of HIV is measured – whether this is based on self-report data or laboratory-confirmed testing. It has also been suggested that a possible reason that prevalence estimates for trans women are so high is because many researchers rely heavily on methods such as convenience sampling, and may end up over-sampling trans female sex workers, thereby inflating prevalence. Prior research has also been unable to provide estimates of HIV prevalence for trans people in different world regions.

The study

The researchers conducted a systematic review and meta-analysis of all studies published between 2000 and 2019 pertaining to HIV prevalence among trans people. They included 98 studies from 34 countries published in any language that included laboratory-confirmed HIV prevalence. Most studies (78) pertained to trans women, four related to trans men and 16 to both. In total, 48,604 trans women from 34 countries and 6,460 trans men from six countries (Australia, Brazil, Canada, Italy, Spain and the US) were included.

As opposed to merely pooling prevalence rates, they calculated standardised prevalence rates based on country-level HIV prevalence by year of data collection. This was done globally and for different geographic regions. The researchers also considered prevalence estimate differences generated by different types of sampling and estimated prevalence in the pre-PrEP and post-PrEP periods in the US specifically.

Global and regional HIV prevalence

Globally, overall standardised HIV prevalence was 19.9% (95% Confidence Interval [CI] 14.7% – 25.1%) for trans women and 2.56% (95% CI 0.0% – 5.9%) for trans men. Trans women had a staggering 66 times higher odds of being infected with HIV compared with HIV rates for with people 15 years and older in the general population, while for trans men, this was 6.8 times higher.

For trans women, regional analysis revealed that standardised HIV prevalence was at 29.9% (95% CI 22.5% – 37.3%) in a sub-Saharan African sample of 1,192 individuals, with 21.5 times higher odds of infection compared to the general population. In Latin America, prevalence was 25.9% (95% CI 20.0% – 31.8%), with a 95.6 times higher chance of having HIV in a sample of 7,917 individuals. In Asia, HIV prevalence was 13.5% (95% CI 2.3% – 17.7%) among a sample of 14,798 people, with 68 times higher odds. Lastly, in Australia, Europe, and North America standardised HIV prevalence was 17.1% (95% CI 13.1% – 21.1%), with an odds ratio of 48.4 in a sample of 24,697 individuals.

The most commonly used sampling methods provided prevalence estimates in similar ranges. Respondent-driven sampling, which is based on networks of connected individuals, was used in 33 studies, and was associated with the highest prevalence at 23.3% (95% CI 18.0% – 28.4%). When prevalence rates were based on patients at STI clinics (used in 26 studies), standardised prevalence was lower at 17.4% (95% CI 12.2% – 22.7%). Convenience sampling, based on finding easily accessible groups of trans people – such as at a dedicated trans health clinic – yielded a similar prevalence to the overall estimate for trans women, at 19.7% (95% CI 14.8% – 24.5%).

Interestingly, the researchers did not find evidence of reduced prevalence after the introduction of PrEP in the US. In fact, prevalence increased among trans women from 18.4% (95% CI 14.8% – 22.0%) in the pre-PrEP period (1997 to 2011) to 23.7% (95% CI 20.2% – 27.2%) for the period 2012 to 2017. This could have to do with there only being six studies on prevalence conducted after the introduction of PrEP, leading to a skewed estimate. The researchers also note that PrEP provision for trans women has been limited so far.

Conclusion

“This systematic review and meta-analysis affirms that transgender individuals are disproportionately burdened by HIV, and that this is the case for not only trans feminine individuals, but also for trans masculine individuals. Using a larger pooled sample than ever compiled before, we ascertained that trans masculine individuals almost seven times more likely to have HIV, and trans feminine individuals are 66 times more likely to have HIV, than other individuals over 15 years of age,” the authors concluded.

“Additionally, based on data from 34 countries across major geographic regions, we found support for the contention that the disproportionate burden for HIV carried by transgender individuals is a worldwide phenomenon, and that some regions, such as Africa and Latin America, may be impacted more than others.”

References

Stutterheim S et al. The worldwide burden of HIV in transgender individuals: An updated systematic review and meta-analysis. PLOS ONE 16: e0260063, 2021 (open access).

https://doi.org/10.1371/journal.pone.0260063