Department of Mathematics and Institute of Applied Mathematics, University of British Columbia, Vancouver, BC V6T 1Z2, Canada.
British Columbia Centre for Disease Control, 655 W 12th Ave., Vancouver, BC V5Z 4R4, Canada.
Epidemics. 2017 Sep;20:73-83. doi: 10.1016/j.epidem.2017.03.002. Epub 2017 Mar 11.
HIV infection cannot be detected immediately after exposure because plasma viral loads are too small initially. The duration of this phase of infection (the "eclipse period") is difficult to estimate because precise dates of exposure are rarely known. Therefore, the reliability of clinical HIV testing during the first few weeks of infection is unknown, creating anxiety among HIV-exposed individuals and their physicians. We address this by fitting stochastic models of early HIV infection to detailed viral load records for 78 plasma donors, taken during the period of exposure and infection. We first show that the classic stochastic birth-death model does not satisfactorily describe early infection. We therefore apply a different stochastic model that includes infected cells and virions separately. Since every plasma donor in our data eventually becomes infected, we must condition the model to reflect this bias, before fitting to the data. Applying our best estimates of unknown parameter values, we estimate the mean eclipse period to be 8-10 days. We further estimate the reliability of a negative test t days after potential exposure.
HIV 感染后不能立即被检测到，因为最初血浆中的病毒载量很小。感染的这个阶段（“潜伏期”）持续时间很难估计，因为接触的确切日期很少被知晓。因此，在感染的最初几周内进行 HIV 临床检测的可靠性尚不清楚，这给 HIV 暴露者及其医生带来了焦虑。我们通过为 78 名血浆供体在感染期和暴露期采集的详细病毒载量记录拟合早期 HIV 感染的随机模型来解决这个问题。我们首先表明，经典的随机生死模型不能令人满意地描述早期感染。因此，我们应用一种不同的随机模型，分别包含受感染的细胞和病毒颗粒。由于我们数据中的每个血浆供体最终都被感染，因此在对数据进行拟合之前，我们必须对模型进行条件处理，以反映这种偏差。应用我们对未知参数值的最佳估计，我们估计平均潜伏期为 8-10 天。我们进一步估计在潜在暴露后的 t 天进行阴性检测的可靠性。
