Contact tracing for COVID-19

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Countries should follow the latest Finding ECDC contacts advice.

To learn more, please take the online course “Contact Tracing in the Context of the COVID-19 Response”.

Principles of contact tracing

The goal of identifying and managing contacts of COVID-19 cases is to promote early diagnosis and interrupt transmission by quickly identifying and managing any secondary cases that may arise as a result of transmission to from primary cases. This is achieved by

  • quickly identify contacts of a case of COVID-19;
  • providing contacts with information on self-quarantine, good hand hygiene and respiratory etiquette, and advice on what to do if they develop symptoms;
  • test all contacts who have been exposed to high-risk COVID-19 cases, whether symptomatic or not, as soon as possible after their identification to allow for more in-depth contact tracing;
  • test all contacts who have had low risk exposure to cases of COVID-19 in settings where transmission is likely and / or the population is vulnerable to severe COVID-19;
  • test all contacts that become symptomatic.

Contact tracing is a key tool in breaking the chains of transmission. For countries with high transmission, contact tracing will complement other measures, such as physical distancing, and help reduce transmission. For countries with lower transmission levels, contact tracing is key to managing epidemics and controlling transmission.

For contact tracing to be effective, it must be fast. This includes testing cases as soon as possible after symptoms appear, which requires a high level of public awareness and easy access to testing. Test turnaround time should be minimized and contacts sought as soon as possible after a positive result. While waiting for their test results, symptomatic people may be encouraged to inform their loved ones and suggest that they observe physical distancing measures until the result is known.

Below you will find more information about the different settings.

Contact tracing for variants of concern (VOCs)

The ECDC Rapid Risk Assessment contains regularly updated information and each risk assessment has a section on contact tracing. The latest risk assessment is available here.

When a case is suspected of being infected with a VOC, contact tracing can help prevent the establishment of the VOC in the country. It can also be used to investigate the source of infection of a newly identified case – known as ‘backward contact tracing’. It may also allow the identification of other cases related to the source of the infection. Additional contact tracing can then take place in these additional cases.

For cases suspected of being infected with a VOC (for example following laboratory pre-screening or an epidemiological link), reinforced contact tracing measures may be considered. These enhanced measures are described in the ECDC risk assessment Risk related to the spread of new variants of SARS-CoV-2 of concern in the EU / EEA – first update.

Countries using mobile applications to support contact tracing are encouraged to monitor the number of contacts tested positive among those notified, or to apply similar measures to understand if parameter settings require calibration – for example due to of a more transmissible variant. The ECDC guidance on mobile applications contains more details on the evaluation and calibration of parameters.

Contact tracing for vaccinated people

Interim guidance on contact tracing recommendations for people who have been vaccinated can be found here.

As indicated in the interim guidelines above, vaccinated contacts who have been exposed to a confirmed case should continue to be managed according to existing ECDC guidelines. However, health authorities may consider conducting a risk assessment on a case-by-case basis and subsequently classifying some fully vaccinated individuals as low-risk contacts. In the assessment, factors that should be taken into consideration include the local epidemiological situation in terms of circulating variants; the type of vaccine received; age of contact or risk of further transmission to vulnerable people through contact.

Monitoring

ECDC and WHO encourage countries to monitor the effectiveness of their contact tracing operations to identify areas where coverage or timeliness needs to be improved (see the ECDC publication Monitoring Framework and assessment of COVID-19 response activities in the EU / EEA and the UK). To learn more about the transmissibility and characteristics of VOCs, countries are encouraged to collect and analyze contact tracing data from these cases and share the results with ECDC, WHO and other countries in the world. ‘EU / EEA.

Data gathering

This reporting protocol describes the collection of data regarding contact tracing. The data collection aims to help assess the effectiveness and efficiency of contact tracing operations, provide information on the transmission of SARS-CoV-2, and provide contextual information on the progression of the pandemic to adapt response measures.

Mobile app

Countries using mobile applications for contact tracing are also encouraged to refer to the ECDC guidelines on mobile applications in support of contact tracing and to monitor their effectiveness using the indicator framework. joint WHO-ECDC.

Regarding VOCs, countries are encouraged to monitor the number of contacts tested positive among those notified, or to apply similar measures in order to understand if the parameter settings require calibration, for example due to a more variant. transmissible. The ECDC guidance on mobile applications contains more details on the evaluation and calibration of parameters.

Passenger tracking forms

On May 27, 2021, the European Commission published Implementing Decision 2021/858 describing the function of the Digital Passenger Tracking Form (dPLF) in the EU / EEA.

Additional contact tracing materials, including those related to particular contexts or populations

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