CDC COVID-19 Response Team.
J Public Health Manag Pract. 2022;28(1):16-24. doi: 10.1097/PHH.0000000000001420.
The implementation of case investigation and contact tracing (CICT) for controlling COVID-19 (caused by SARS-CoV-2 virus) has proven challenging due to varying levels of public acceptance and initially constrained resources, especially enough trained staff. Evaluating the impacts of CICT will aid efforts to improve such programs.
Estimate the number of COVID-19 cases and hospitalizations averted by CICT and identify CICT processes that could improve overall effectiveness.
We used data on the proportion of cases interviewed, contacts notified or monitored, and days from testing to case and contact notification from 14 jurisdictions to model the impact of CICT on cumulative case counts and hospitalizations over a 60-day period. Using the Centers for Disease Control and Prevention's COVIDTracer Advanced tool, we estimated a range of impacts by assuming either contacts would quarantine only if monitored or would do so upon notification of potential exposure. We also varied the observed program metrics to assess their relative influence.
Performance by jurisdictions varied widely. Jurisdictions isolated between 12% and 86% of cases (including contacts that became cases) within 6 to 10 days after infection. We estimated that CICT-related reductions in transmission ranged from 0.4% to 32%. For every 100 remaining cases after other nonpharmaceutical interventions were implemented, CICT averted between 4 and 97 additional cases. Reducing time to case isolation by 1 day increased averted case estimates by up to 15 percentage points. Increasing the proportion of cases interviewed or contacts notified by 20 percentage points each resulted in at most 3 or 6 percentage point improvements in averted cases.
We estimated that CICT reduced the number of COVID-19 cases and hospitalizations among all jurisdictions studied. Reducing time to isolation produced the greatest improvements in impact of CICT.
实施病例调查和接触者追踪（CICT）以控制 COVID-19（由 SARS-CoV-2 病毒引起）由于公众接受程度不同和最初资源有限，尤其是足够的训练有素的工作人员，这一措施面临挑战。评估 CICT 的影响将有助于努力改进此类计划。
估计 CICT 避免的 COVID-19 病例和住院人数，并确定可以提高整体效果的 CICT 流程。
我们使用了来自 14 个司法管辖区的关于接受访谈的病例比例、通知或监测的接触者以及从检测到病例和接触者通知的天数的数据，来模拟 CICT 对 60 天内累积病例数和住院人数的影响。使用疾病控制和预防中心的 COVIDTracer 高级工具，我们通过假设接触者仅在监测时或在接到潜在暴露通知时进行隔离，来估计了一系列的影响。我们还改变了观察到的项目指标，以评估它们的相对影响。
各司法管辖区的表现差异很大。各司法管辖区在感染后 6 至 10 天内隔离了 12%至 86%的病例（包括成为病例的接触者）。我们估计，CICT 相关的传播减少幅度在 0.4%至 32%之间。在实施其他非药物干预措施后，每 100 例剩余病例中，CICT 避免了 4 至 97 例额外病例。将病例隔离时间缩短 1 天，可使避免的病例估计值增加多达 15 个百分点。将接受访谈的病例比例或通知的接触者比例各提高 20 个百分点，最多可使避免的病例数提高 3 或 6 个百分点。
我们估计 CICT 减少了所有研究司法管辖区的 COVID-19 病例和住院人数。缩短隔离时间可最大程度地提高 CICT 的影响。
