AIDS Epidemic Reference Laboratory, National Institute of Health, Lisbon, Portugal.
HIV Med. 2009 Mar;10(3):182-90. doi: 10.1111/j.1468-1293.2008.00669.x. Epub 2009 Jan 7.
A prospective study was carried out to assess HIV-1 and HIV-2 mother-to-child transmission (MTCT) rates in Portugal between 1999 and 2005 by analysing the proportion of diagnosed infected children born to HIV-positive mothers.
Serial blood samples were collected from 1315 children at risk of HIV-1 infection, 131 children at risk of HIV-2 infection and six children at risk of both HIV-1 and HIV-2 infections attending 25 Health Institutions. HIV proviral DNA was detected by nested polymerase chain reaction (PCR) and statistical analysis was performed using spss.
DNA PCR using HIV-1 and HIV-2 long terminal repeat (LTR) primers amplified 92.5% and 75% of maternal HIV infections, respectively. Overall, MTCT occurred in 3.4% [95% confidence interval (CI) 2.5-4.6%] of HIV-1 and 1.5% (95% CI 0.2-5.4%) of HIV-2 mother-child pairs. A significant decrease in HIV-1 MTCT was observed with time, from 7.0% (95% CI 2.6-14.6%) in 1999 to 0.5% (95% CI 0.0-2.5%) in 2005. HIV MTCT was associated with an absence of antiretroviral therapy in infected pregnant women (P<0.0001). Of the 48 infected children (46 with HIV-1 and two with HIV-2), the schedule of blood sample collection was followed for only 26 children. In 14 (53.8%) of those 26 children the infections were diagnosed in the first sample collected before they were 48 h old, suggesting in utero transmission. Despite the national recommendations for antenatal HIV testing, a high overall proportion (22.2% for HIV-1 and 44.3% for HIV-2) of mothers did not access any MTCT prevention measures, mostly because of late diagnosis in pregnancy. A small but significant proportion of HIV-2 infection was found in mothers with no identifiable link with West Africa.
HIV-2 transmission rates are low (1.5% in this study), and this may have led to a lower uptake of interventions, but in the absence of interventions transmission does occur. HIV-1 transmission was also associated with a lack of intervention, mostly as a result of late presentation. Use of primers restricted to a single sequence led to false-negative maternal results in a significant proportion of cases. In part this may have been attributable to very low HIV DNA loads as well as primer template mismatches. HIV infection was not documented in children born to mothers with negative HIV DNA PCR results.
通过分析确诊的 HIV 阳性母亲所生感染儿童的比例，对 1999 年至 2005 年期间葡萄牙的 HIV-1 和 HIV-2 母婴传播（MTCT）率进行前瞻性研究。
在 25 家医疗机构中，对 1315 名有感染 HIV-1 风险的儿童、131 名有感染 HIV-2 风险的儿童和 6 名有感染 HIV-1 和 HIV-2 双重风险的儿童采集连续血样。采用巢式聚合酶链反应（PCR）检测 HIV 前病毒 DNA，并使用 spss 进行统计分析。
使用 HIV-1 和 HIV-2 长末端重复（LTR）引物的 DNA PCR 分别扩增了 92.5%和 75%的母体 HIV 感染。总体而言，HIV-1 母婴传播率为 3.4%[95%置信区间（CI）2.5-4.6%]，HIV-2 母婴传播率为 1.5%（95%CI 0.2-5.4%）。随着时间的推移，HIV-1 MTCT 显著下降，从 1999 年的 7.0%（95%CI 2.6-14.6%）降至 2005 年的 0.5%（95%CI 0.0-2.5%）。感染孕妇未接受抗逆转录病毒治疗与 HIV MTCT 相关（P<0.0001）。在 48 名感染儿童（46 名感染 HIV-1，2 名感染 HIV-2）中，只有 26 名儿童按规定采集了血样。在这 26 名儿童中，有 14 名（53.8%）在 48 小时前采集的第一份血样中被诊断出感染，提示宫内传播。尽管有全国性的 HIV 产前检测建议，但仍有相当大比例（HIV-1 为 22.2%，HIV-2 为 44.3%）的母亲未采取任何 MTCT 预防措施，主要是因为在妊娠晚期才确诊。在没有明确与西非有关联的母亲中发现了少量但意义重大的 HIV-2 感染。
HIV-2 传播率较低（本研究为 1.5%），这可能导致干预措施的采用率较低，但如果不采取干预措施，传播仍会发生。HIV-1 传播也与缺乏干预措施有关，主要是由于就诊较晚。使用仅针对单一序列的引物会导致相当一部分母体结果呈假阴性。这在一定程度上可能归因于 HIV DNA 载量非常低以及引物模板不匹配。在 HIV DNA PCR 结果为阴性的母亲所生的儿童中，没有记录到 HIV 感染。
