UK Health Security Agency South of England, Bristol, UK.
Population Health Sciences, University of Bristol, Bristol, UK
BMJ Open. 2023 Oct 12;13(10):e064982. doi: 10.1136/bmjopen-2022-064982.
In September 2020, 15 861 SARS-CoV-2 case records failed to upload from the Second Generation Surveillance System (SGSS) to the Contact Tracing Advisory Service (CTAS) tool, delaying the contact tracing of these cases. This study used CTAS data to determine the impact of this delay on population health outcomes: transmission events, hospitalisations and mortality. Previously, a modelling study suggested a substantial impact.
Observational study.
England.
Individuals testing positive for SARS-CoV-2 and their reported contacts.
Secondary attack rates (SARs), hospitalisations and deaths among primary and secondary contacts were calculated, compared with all other concurrent, unaffected cases. Affected SGSS records were matched to CTAS records. Successive contacts and cases were identified and matched to hospital episode and mortality outcomes.
Initiation of contact tracing was delayed by 3 days on average in the primary cases in the delay group (6 days) compared with the control group (3 days). This was associated with lower completion of contact tracing: 80% (95% CI: 79% to 81%) in delay group and 83% (95% CI: 83% to 84%) in control group. There was some evidence to suggest increased transmission to non-household contacts among those affected by the delay. The SAR for non-household contacts was higher among secondary contacts in the delay group than the control group (delay group: 7.9%, 95% CI: 6.5% to 9.2%; control group: 5.9%, 95% CI: 5.3% to 6.6%). There did not appear to be a significant difference between the delay and control groups in the odds of hospitalisation (crude OR: 1.1 (95% CI: 0.9 to 1.2)) or death (crude OR: 0.7 (95% CI: 0.1 to 4.0)) among secondary contacts.
Our analysis suggests that the delay in contact tracing had a limited impact on population health outcomes; however, contact tracing was not completed for all individuals, so some transmission events might not be captured.
2020 年 9 月，第二代监测系统（SGSS）有 15861 例 SARS-CoV-2 病例记录未能上传至接触者追踪咨询服务（CTAS）工具，导致这些病例的接触者追踪工作延迟。本研究使用 CTAS 数据来确定这种延迟对人群健康结果的影响：传播事件、住院和死亡。此前的一项建模研究表明，这种延迟将产生重大影响。
观察性研究。
英格兰。
SARS-CoV-2 检测呈阳性的个体及其报告的接触者。
初级和次级接触者的二次感染率（SAR）、住院和死亡情况与所有其他同时发生的、未受影响的病例进行比较。受影响的 SGSS 记录与 CTAS 记录相匹配。识别连续接触者和病例，并将其与住院和死亡结局相匹配。
与对照组（3 天）相比，延迟组中初级病例的接触者追踪平均延迟 3 天（6 天）。这与接触者追踪完成率较低有关：延迟组为 80%（95%CI：79%至 81%），对照组为 83%（95%CI：83%至 84%）。有证据表明，延迟组中接触者追踪对非家庭接触者的传播有所增加。延迟组中非家庭接触者的 SAR 高于对照组（延迟组：7.9%，95%CI：6.5%至 9.2%；对照组：5.9%，95%CI：5.3%至 6.6%）。在次级接触者中，住院（粗 OR：1.1（95%CI：0.9 至 1.2））或死亡（粗 OR：0.7（95%CI：0.1 至 4.0））的可能性，在延迟组和对照组之间似乎没有显著差异。
我们的分析表明，接触者追踪的延迟对人群健康结果的影响有限；然而，并非所有个体的接触者追踪都已完成，因此可能无法捕捉到一些传播事件。
