Toronto East Health Network, Michael Garron Hospital, 825 Coxwell Avenue, Toronto, Ontario M4C 3E7, Canada.
Sunnybrook Health Sciences Centre, 2075 Bayview Ave, Toronto, Ontario M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, King's College Cir, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
J Infect. 2022 Dec;85(6):666-670. doi: 10.1016/j.jinf.2022.10.027. Epub 2022 Oct 22.
SARS-CoV-2 shedding has changed as new variants have emerged. It is important to understand the trajectory of PCR positivity due to Omicron in vaccinated populations.
Double- or triple-vaccinated adult household contacts of individuals with COVID-19 self-collected oral-nasal swabs for 14 days. A hierarchical linear model estimated viral load trajectories and an exploratory logistic regression model assessed for factors associated with viral detection before symptom onset.
Forty-one participants developed COVID-19 with 37 (90%) symptomatic. Viral load peaked 3 days after symptom onset at a median concentration of 8.83 log copies/milliliter (range 5.95-10.32) and the mean difference between participants with two or three COVID-19 vaccine doses was 0.02 log copies/milliliter (95% CI -0.13 to 0.16). PCR positivity began with a range of 4 days prior to 3 days after symptom onset and was positive on the day of symptom onset in 76% (28/37). SARS-CoV-2 detection on the day of symptom onset was less likely among those with 2 vaccine doses (OR 0.13, 95%CI 0.02-0.79). 68% (25/37) of infected participants had detectable SARS-CoV-2 with Ct<30 at 7 days after symptom onset.
Peak viral load and duration of PCR positivity were similar in participants with COVID-19 after two versus three COVID-19 vaccine doses. Onset of viral detection relative to symptom onset was variable.
随着新变体的出现，SARS-CoV-2 的脱落情况发生了变化。了解接种疫苗人群中奥密克戎导致的 PCR 阳性轨迹非常重要。
COVID-19 患者的双剂或三剂疫苗接种成年家庭接触者自行采集口咽拭子 14 天。使用分层线性模型估计病毒载量轨迹，并使用探索性逻辑回归模型评估与症状出现前病毒检测相关的因素。
41 名参与者发生 COVID-19，其中 37 名（90%）有症状。病毒载量在症状出现后第 3 天达到峰值，中位数浓度为 8.83 对数拷贝/毫升（范围 5.95-10.32），两剂和三剂 COVID-19 疫苗接种者之间的平均差异为 0.02 对数拷贝/毫升（95%CI-0.13 至 0.16）。PCR 阳性在症状出现前 4 天至症状出现后 3 天之间开始，在 76%（28/37）的病例中在症状出现当天呈阳性。两剂疫苗接种者在症状出现当天检测到 SARS-CoV-2 的可能性较低（OR 0.13，95%CI 0.02-0.79）。在症状出现后 7 天，68%（25/37）的感染参与者的 SARS-CoV-2 可检测到 Ct<30。
在两剂和三剂 COVID-19 疫苗接种后发生 COVID-19 的参与者中，病毒载量峰值和 PCR 阳性持续时间相似。与症状出现相比，病毒检测的起始时间是可变的。
