Use of public data to describe COVID-19 contact tracing in Hubei Province and non-Hubei provinces in China between 20 January and 29 February 2020

@#Objective: Contact tracing has been used in China and several other countries in the WHO Western Pacific Region as part of the COVID-19 response. We describe COVID-19 cases and the number of contacts traced and quarantined per case as part of COVID-19 emergency public health response activities in China. Methods: We abstracted publicly available, online aggregated data published in daily COVID-19 situational reports by China’s National Health Commission and provincial health commissions between 20 January and 29 February 2020. The number of new contacts traced by report date was computed as the difference between total contacts traced in consecutive reports. A proxy for the number of contacts traced per case was computed as the number of new contacts traced divided by the number of new cases. Results: During the study period, China reported 80 968 new COVID-19 cases and 659 899 contacts. In Hubei Province, there were 67 608 cases and 264 878 contacts, representing 83% and 40% of the total, respectively. Non-Hubei provinces reported tracing 1.5 times more contacts than Hubei Province; the weekly number of contacts traced per case was also higher in non-Hubei provinces than in Hubei Province and increased from 17.2 in epidemiological week 4 to 115.7 in epidemiological week 9. Discussion: More contacts per case were reported from areas and periods with lower COVID-19 case counts. With other non-pharmaceutical interventions used in China, contact tracing and quarantining large numbers of potentially infected contacts probably contributed to reducing SARS-CoV-2 transmission.

Use of Public Data to Describe COVID-19 Contact Tracing in China during January 20-February 29, 2020

ObjectiveAlthough contact tracing is generally not used to control influenza pandemics, China and several countries in the Western Pacific Region employed contact tracing as part of COVID-19 response activities. To improve understanding on the use of contact tracing for COVID-19 emergency public health response activities, we describe reported COVID-19 contacts traced and quarantined in China and a proxy for number of reported contacts traced per reported case. MethodsWe abstracted publicly available online aggregate data reported from Chinas National Health Commission and provincial health commissions COVID-19 daily situational reports for January 20-February 29, 2020. The number of new contacts traced by report date was computed as the difference between total contacts traced on consecutive reports. A proxy for the number of contacts traced per case was computed as the number of new contacts traced divided by the number of new cases. ResultsDuring January 20-February 29, 2020, China reported 80,968 new COVID-19 cases (Hubei Province = 67,608 [83%]), and 659,899 contacts traced (Hubei Province = 265,617 [40%]). Non-Hubei provinces reported more contacts traced per case than Hubei Province; this difference increased over time. DiscussionAlong with other NPI used in China, contact tracing likely contributed to reducing SARS-CoV-2 transmission by quarantining a large number of potentially infected contacts. Despite reporting only 15% of total cases, non-Hubei provinces had 1.5 times more reported contacts traced compared to Hubei Province. Contract tracing may have been more complete in areas and periods with lower case counts.