Impact of COVID-19 contact monitoring on health outcomes

in a recent study published in medRxiv* Prepress server, investigators evaluated the impact of delayed contact monitoring of coronavirus disease 2019 (COVID-19) cases on health outcomes of transmissions, hospitalizations and deaths of acute acute respiratory syndrome in England in severe coronary artery syndrome (SARS-CoV-2).

Study: Assessing the impact of COVID-19 on the outcome of a follow-up contact with the health outcomes of an incident. Image credit: bob boz / Shutterstock

Contact tracing has been instrumental in assessing the health responses of the general population to SARS-CoV-2 and for identifying contacts with SARS-CoV-2-positive individuals and providing advice on self-isolation to reduce SARS-CoV-2 transmission.

In September 2020, 15,861 COVID-19 case records from the Second Generation Laboratory Surveillance System (SGSS) could not be uploaded to the Contact Tracking Advisory Service (CTAS) data tool and then delayed the contact tracking of COVID-19 cases.

SGSS records contain demographic and diagnostic information from laboratory test reports for patients who tested positive for SARS-CoV-2, and CTAS records show excerpts from SARS-CoV-2 cases, including information on case movements during the infection period, their contacts, and demographic and clinical characteristics. .

About the exam

In this observational study, researchers from the UK Health Safety Agency, the University of Bristol and the University of Cambridge assessed the impact of contact delay in COVID-19 cases on SARS-CoV-2 transmission and hospitalization and death in England. .

The UK Health Safety Agency (UKHSA) issued SGSS records that matched the CTAS records to validate the cases caused by the incident, and successive contacts and cases were identified. The study used CTAS data from SARS-CoV-2-positive individuals and their contacts for the study.

The merger was done in several shifts based on identifier combinations, such as the National Health Service (NHS) number. Unique SGSS identifier, date of birth (DOB). name, surname and postal code.

The CTAS data set included the first cases that caused the incident and these cases have been referred to as the “delay group” and the first cases in the same period (September 30 to October 5, 2020) have not been affected. the event formed a ‘control group’.

Graphs describing the time required to start and complete the case and contact tracking of delay and control groups

Graphs describing the time required to start and complete the case and contact tracking of delay and control groups

People who were in contact with an individual in the first case and people who were in contact with a primary case were described as secondary cases between the 2nd and 14th day after the onset of symptoms, or between the date of the test between secondary cases.

In addition, the contact data set was linked to the COVID-19 data set created at UKHSA Hospital, released on 22 November 2021, and retrieves daily data from two national data sets, the Second Use Services (SUS) data set and Emergency Care. Data. A set that describes patient hospitalizations and the use of emergency services (ECDS), respectively.

The main outcome measures included secondary assault rates (SAR), hospitalizations, and deaths between first-contact and secondary-contact at the same time and compared to unaffected cases.


A total of 15,861 SGSS records were detected as a result of the incident, of which 98% (15,467) matched CTAS records. After clearing the data, 96% (15,285) of the first cases caused by the delay were eligible for analysis. The control team had 43,742 simultaneous cases of primary contact, including all CTAS records unaffected by the incident.

The start of contact tracing was delayed by three days compared to controls in the first contact cases between the delay group compared to the incomplete contact tracing of contacts in the first group of delays (80%) and control cases (83%).

The delay increased the transmission of the virus to non-domestic contacts. Non-home contacts had higher SARs among secondary contacts (7.9%) compared to delay group controls (5.9%). Among the secondary contacts, there were no statistically significant differences between individuals in the delay group and controls in terms of hospitalization (gross odds ratio 1) and death (gross odds ratio 0.7).

Generally, the results of the study revealed that the delay in tracing contacts for COVID-19 cases affected their health.

* Important note

medRxiv it publishes preliminary scientific reports that are not peer-reviewed and therefore should not be considered decisive, do not guide clinical practice / health-related behavior or should not be treated as established information.

Magazine reference:

  • Assessing the impact of COVID-19 case contact delay on the health outcomes of an event, including Lucy Findlater, Livia Pierotti, Charlie Turner, Adrian Wensley, Cong Chen, Shaun Seaman, Pantelis Samartsidis, Andre Charlett, Charlotte Anderson, Gareth Hughes, Matt Hickman, Obaghe Edeghere, Isabel Oliver, medRxiv preprint 2022, DOI:


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