Data from: Optimizing prevention of HIV mother to child transmission: duration of antiretroviral therapy and viral suppression at delivery among pregnant Malawian women

Background: Effective antiretroviral therapy during pregnancy minimizes the risk of vertical HIV transmission. Some women present late in their pregnancy for first antenatal visit; whether these women achieve viral suppression by delivery and how suppression varies with time on ART is unclear. Methods: We conducted a prospective cohort study of HIV-infected pregnant women initiating antiretroviral therapy for the first time from June 2015 to November 2016. Multivariable Poisson models with robust variance estimators were used to estimate risk ratios (RR) and 95% confidence intervals (CI) of the association between duration of ART and both viral load (VL) ≥1000 copies/ml and VL ≥40 copies/ml at delivery. Results: Of the 252 women who had viral load testing at delivery, 40 (16%) and 78 (31%) had VL ≥1000 copies/ml and VL ≥40 copies/ml, respectively. The proportion of women with poor adherence to ART was higher among women who were on ART for ≤12 weeks (9/50 = 18.0%) than among those who were on ART for 13-35 weeks (18/194 = 9.3%). Compared to women who were on ART for ≤12 weeks, women who were on ART for 13-20 weeks (RR = 0.52; 95% CI: 0.36-0.74) or 21-35 weeks (RR = 0.26; 95% CI: 0.14-0.48) had a lower risk of VL ≥40 copies/ml at delivery. Similar comparisons for VL ≥1000 copies/ml at delivery showed decrease in risk although not significant for those on ART 13-20 weeks. Conclusion: Longer duration of ART during pregnancy was associated with suppressed viral load at delivery. Early ANC attendance in pregnancy to facilitate prompt ART initiation for HIV-positive women is essential in the effort to eliminate HIV vertical transmission.

背景：妊娠期接受有效的抗逆转录病毒治疗（antiretroviral therapy, ART）可最大限度降低HIV垂直传播风险。部分孕妇直至妊娠晚期才首次接受产前检查，此类孕妇能否在分娩前实现病毒抑制，以及病毒抑制状态随抗逆转录病毒治疗时长的变化规律尚不明确。
方法：本研究于2015年6月至2016年11月期间，针对首次启动抗逆转录病毒治疗的HIV感染孕妇开展前瞻性队列研究。采用稳健方差估计的多变量泊松模型，估算抗逆转录病毒治疗时长与分娩时病毒载量（viral load, VL）≥1000拷贝/ml、VL≥40拷贝/ml两者间关联的风险比（risk ratios, RR）及95%置信区间（confidence intervals, CI）。
结果：252名于分娩时接受病毒载量检测的孕妇中，分别有40名（16%）、78名（31%）的分娩时病毒载量≥1000拷贝/ml、≥40拷贝/ml。抗逆转录病毒治疗时长≤12周的孕妇，其ART治疗依从性不佳的比例（9/50=18.0%）高于治疗时长13~35周的孕妇（18/194=9.3%）。与治疗时长≤12周的孕妇相比，治疗时长13~20周（RR=0.52；95%CI：0.36~0.74）或21~35周（RR=0.26；95%CI：0.14~0.48）的孕妇，分娩时VL≥40拷贝/ml的风险显著更低。针对分娩时VL≥1000拷贝/ml的类似对比显示，风险有所降低，但对于治疗时长13~20周的孕妇，该差异未达到统计学显著性。
结论：妊娠期抗逆转录病毒治疗时长越长，分娩时病毒载量得到抑制的比例越高。为HIV感染孕妇尽早提供产前检查以实现抗逆转录病毒治疗的及时启动，对于消除HIV垂直传播至关重要。