尋求超越設施以消除垂直傳播
資料來源：www.thelancet.com/hiv Vol 10 January 2023，財團法人台灣紅絲帶基金會編譯
在 The Lancet HIV 中，Goodluck Willey Lyatuu 及其同事對坦桑尼亞達-累斯-薩拉姆的 HIV 垂直傳播進行了大規模估計。作者前瞻性地追踪了 2015 年至 2017 年接受產前檢查的一組婦女，並估計了產後 18 個月內嬰兒的垂直傳播率。在此追踪期間的 13,251 名婦女中，有 159 名嬰兒被診斷出感染了 HIV，垂直傳播率低至 1·4%，令人印象深刻。與較差的求醫和順從性行為相關的因素與垂直傳播有最密切相關：遲到產前檢查、既往未使用 ART、晚期 HIV 疾病，和使用二線 ART 方案。
這個評價有很多優點。 首先，它解決了撒哈拉以南非洲垂直傳播這一重要而及時的話題。儘管許多撒哈拉以南非洲國家已經達到或超過 90-90-90 的成人治療里程碑，但它們在兒科治療結果和垂直傳播目標方面落後。其次，它是對垂直傳播的最大真實世界評估之一。 迄今為止，在東非最大城市達-累斯-薩拉姆226 家為 90% 的顧客提供垂直傳播預防服務的診所中，對婦女進行了檢查。第三，它追踪嬰兒進入產後期，從第一次產前檢查開始累計跟踪近 2 年。最後，作者將母嬰配對聯繫起來，以更好地了解母體因素如何影響嬰兒的結局。該分析強調了當母親開始治療並且她們和她們的嬰兒繼續參與照護時預防垂直傳播的照護計畫的有效性。
作者將他們的估計值 1·4% 與聯合國愛滋病規劃署在同一時期對坦桑尼亞的模型估計值 11% 進行了對比，形成了鮮明的差異。在 2016 年至 2017 年進行的具有全國代表性的坦桑尼亞愛滋病毒影響調查中觀察到類似的值 (10·5%)。這種差異是驚人的。坦桑尼亞是否準備好消除垂直傳播，還是需要大力加強努力？ 是什麼導致了這種巨大的差異？我們假設在此分析中未觀察到的母嬰配對有助於解釋這種差異。
在參加預防垂直傳播照護計畫的近 23,000 名感染愛滋病毒的孕婦中，近四分之三的人在 18 個月時沒有愛滋病毒結果數據。這些被排除的母嬰配對中有很大一部分 (42%) 有不良的嬰兒結局（流產、死產或死亡）、不良的孕產婦結局（孕產婦死亡或失訪），或者沒有記錄妊娠或 HIV 結局。當作者在敏感性分析中對這些失踪的嬰兒之 HIV 結果進行建模時，他們的結果明顯不同。他們沒有觀察到 1·4% 的垂直傳播率，而是估計了 7·4% 的比率，這個值更接近聯合國愛滋病規劃署的估計值。此外，在分析中包含的母嬰配對中，超過一半的母嬰在 18 個月結束時消失了。與接受觀察的嬰兒相比，不接受照護的嬰兒可能會有更糟糕的結果，包括新的 HIV 感染。
還有兩組的母嬰配對未被納入研究人群。首先，沒有開始 ART 的女性被排除在外。該組包括未進行產前檢查、未接受 HIV 檢測或拒絕接受 ART 的女性。儘管在每個亞組中的女性人數可能很少，但她們對垂直傳播的貢獻可能大得不成比例。此外，該分析似乎不包括在懷孕後期或母乳喂養期間感染 HIV 的女性，其與高得多的垂直傳播相關的事件，以及不成比例的垂直傳播事件。事實上，根據 Spectrum 的模型估計，坦桑尼亞只有一小部分垂直傳播源於開始並繼續接受 ART 的母親，即在此分析中被捕獲的人口。如果達-累斯-薩拉姆的感染分佈與坦桑尼亞的整體分佈相似，則分析中不會捕獲大多數垂直傳播。
這些發現意味著什麼？ 這個觀察世代中的低傳播率非常令人鼓舞，顯示預防垂直傳播的照護計畫對於那些參與和存留在照護的人來說運作得非常好。相比之下，該計畫的其他方面需要更多關注——確保所有感染 HIV 的孕婦開始抗反轉錄病毒治療，在計畫中丟失時重新參與照護，並在懷孕和哺乳期間能提供綜合預防（如果有風險）。這些活動將使坦桑尼亞和類似的預防垂直傳播的照護計畫能夠為實現消除愛滋病毒垂直傳播而走完最後一英哩路。
NER 部分由美國國家衛生研究院 (NIH) 透過贈款 R21MH125705 和 R01 MH124526 提供支持。
BHC 得到 NIH 資助 K24 AI120796 和 R01 AI131060 的支持。
我們聲明沒有競爭利益。
*Nora E Rosenberg,Benjamin H Chi Nora_Rosenberg@unc.edu
美國北卡羅來納州教堂山，北卡羅來納大學教堂山分校， 健康行為系 (NER)，婦產科 (BHC) 。
Looking beyond facilities to eliminate vertical transmission
www.thelancet.com/hiv Vol 10 January 2023
In The Lancet HIV, Goodluck Willey Lyatuu and colleagues present large-scale estimates of vertical HIV transmission in Dar es Salaam, Tanzania. The authors prospectively follow a cohort of women who presented for antenatal care from 2015 to 2017 and estimate vertical transmission rates in their infants up to 18-months post-partum. Of 13 251 women followed over this period, 159 infants were diagnosed with HIV, representing an impressively low vertical transmission rate of 1·4%. Factors related to poor care-seeking and adherence behaviours were most strongly associated with vertical transmission: late presentation to antenatal care, lack of previous ART use, advanced HIV disease, and use of second-line ART regimens.
This evaluation has many strengths. First, it addresses the important and timely topic of vertical transmission in sub-Saharan Africa. Although many sub-Saharan Africa countries have reached or exceeded 90-90-90 treatment milestones for adults, they lag behind on paediatric treatment outcomes and vertical transmission goals. Second, it is among the largest real-world evaluations of vertical transmission to date, examining women from 226 clinics, which serve 90% of clients for the prevention of vertical transmission in Dar es Salaam, the largest city in east Africa. Third, it follows infants well into the post-partum period, with nearly 2 years of cumulative follow-up from the first antenatal visit. Finally, the authors link mother–infant pairs to better understand how maternal factors affect infant outcomes. This analysis underscores the effectiveness of a care programme for the prevention of vertical transmission when mothers start treatment and they and their infants remain engaged in care.
The authors contrast their estimate of 1·4% to the UNAIDS modelled estimate of 11% for Tanzania during this same period, a stark difference. A similar value (10·5%) was observed in the nationally representative Tanzania HIV Impact Survey done from 2016 to 2017. This difference is striking. Is Tanzania poised to eliminate vertical transmission or does it need to dramatically intensify its efforts? What accounts for this large discrepancy? We hypothesise that mother–infant pairs who were not observed in this analysis help to explain this discrepancy.
Among almost 23,000 pregnant women living with HIV who were enrolled in the care programme for the prevention of vertical transmission, nearly three-quarters did not have HIV outcome data at 18 months. A large portion (42%) of these excluded mother–infant pairs had adverse infant outcomes (miscarriage, stillbirth, or death), adverse maternal outcomes (maternal death or loss to follow-up), or no pregnancy or HIV outcome recorded. When the authors modelled these missing infant HIV outcomes in a sensitivity analysis, their results were meaningfully different. Rather than observing a 1·4% vertical transmission rate, they estimated a 7·4% rate, a value much closer to the UNAIDS estimate. Additionally, of the mother–infant pairs who were included in the analysis, more than half were lost by the end of the 18-month period. Infants who defaulted from care probably had worse outcomes, including new HIV infection, compared with infants who were observed.
There are also two groups of mother–infant pairs who were not captured in the study population. First, women who did not start ART were omitted. This group includes women who did not have an antenatal visit, were not tested for HIV, or declined ART. Although the number of women in each of these subgroups is probably small, their contribution to vertical transmission might be disproportionately large. Additionally, the analysis does not appear to include women who acquired HIV later in pregnancy or during the breastfeeding period, events associated with much higher vertical transmission, and a disproportionate share of vertical transmission events. In fact, according to modelled estimates by Spectrum, only a small fraction of vertical transmissions in Tanzania stem from mothers who start and remain on ART, the population captured in this analysis. If the distribution of infections in Dar es Salaam is similar to the overall Tanzanian distribution, the majority of vertical transmissions would not have been captured in the analysis.
What are the implications of these findings? The low transmission rates in this observational cohort are highly encouraging and show that the care programme for the prevention of vertical transmission is functioning extremely well for those engaged and retained in care. In contrast, greater attention is needed in other dimensions of the programme— ensuring that all pregnant women living with HIV start ART, are re-engaged in care when lost, and offered combination prevention during the pregnancy and breastfeeding periods if at risk. Such activities will allow Tanzania and similar care programmes for the prevention of vertical transmission to go the last mile towards achieving elimination of vertical HIV transmission.
NER is supported, in part, through the National Institutes of Health (NIH) through grants R21MH125705 and R01 MH124526.
BHC is supported by NIH grants K24 AI120796 and R01 AI131060.
We declare no competing interests.
*Nora E Rosenberg,Benjamin H Chi Nora_Rosenberg@unc.edu
Department of Health Behavior (NER), Department of Obstetrics and Gynecology (BHC), University of North Carolina at Chapel Hill, Chapel Hill, NC,