ConTESSA: Interactive Tool to Estimate Impact of Contact Tracing

ConTESSA: Interactive Tool to Estimate Impact of Contact Tracing >> Measuring and Maximizing Impact of COVID-19 Contact Tracing

The Shire has implemented a contact tracing program to reduce the spread of SARS-CoV-2. They estimate that in the last four weeks, they had an average of 6,250 confirmed cases of COVID-19 per week, and recorded 200 total deaths due to COVID-19 in the last two weeks. Contact tracers were able to successfully isolate an average of 4,375 individuals per week with known SARS-CoV-2 infection, on average within 3 days of symptom onset. Sample collection for testing typically occurred the day after symptom onset.

Household contact tracing was very successful: 90% of household contacts were reached and quarantined on the same day that the case was isolated. Community contact tracing was more challenging. Only 35% of community contacts were identified and quarantined, normally 2 days after the case was isolated.

Shire epidemiologists believe that about 0.75% of infected individuals die of COVID-19, and that on average, individuals live with 3 other people and report 2 to 4 contacts outside of the household in the last two weeks.

Use the worksheet to prepare the ConTESSA inputs according to the Shire’s scenario described above. Then enter these inputs into ConTESSA in order to answer quiz questions below.

What percentage of infections in the community were detected (hint: derived from S1 and S2 in ConTESSA)?

Please enter only numerals – the % symbol is not required.

1 point

The reproductive number should not change, because only the delay from symptom onset to isolation is affected.

The reproductive number should decrease, because more individuals would be isolated following sample collection.

The reproductive number should decrease, because individuals would on average be isolated more quickly.

The reproductive number should decrease, because contacts would on average be quarantined more quickly.

The reproductive number should not change, because decreasing the delay to isolation by 1 day would have a negligible effect.

The file can be downloaded to your local device by clicking here:

contessa-inputs-module2.yaml

Use the interactive figures in the Dashboard to assess the impact of each of the changes described below. Recall that the figures in the dashboard allow you to explore how the impact of your program would change if any one particular metric value changes, keeping all of the other values constant. In this example scenario, which of the following changes would have the greatest impact on the reproductive number?

1 point

Reducing the delay to quarantine of household contacts, such that household contacts are on average quarantined on the same day as the case is isolated, 7 days after symptom onset of the case.

Providing additional support and incentives for household members to remain in quarantine, such that 90% of household contacts are identified and quarantined.

Increasing availability of community testing, such that the proportion of infections in the community detected and isolated through surveillance increases to 30%.

Dedicating more staff members towards identifying community contacts, such that 70% of community contacts are identified and quarantined.

Asking individuals to begin isolation on the day of sample collection, such that the average number of days between symptom onset of a case and when they are told to isolate is 5 days. The timing for identification and quarantine of contacts, which is initiated only after a positive test result is returned, is unaffected.

ConTESSA: Interactive Tool to Estimate Impact of Contact Tracing >> Measuring and Maximizing Impact of COVID-19 Contact Tracing

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