Table 1 Key Performance Indicators (KPI) framework evaluating the Catalan Contact Tracing (CT) program

1. Percentage of cases with identified CC

1.1. Number of confirmed cases

KPI1 is obtained from the division of 1.2 by 1.1, which are both direct outputs from MCC extractions. Results are stratified geographically and temporally

80%

Output indicator reflecting the system’s capacity to conduct case investigation and contact elicitation. The higher it is, the greater impact can the CT program have.

1.2. Number of confirmed cases with identified CC

2. Average number of CC per case

2.1. Number of identified CC

KPI2 is obtained from the division of 2.1 by 1.2. Both 2.1, 2.2 and 2.3 are direct outputs from MCC. Results are stratified by age, geo-temporally and setting of exposure

5

Output indicator translating both the quality and quantity of contact elicitation. Its disaggregation by setting of exposure informs other COVID-19 control measures, as well as facilitates index cases prioritization in case of high ratios of contacts per case, with the goal to prioritize high risk settings and timely detect potential clusters, trace CCs and avoid uncontrolled community transmission.

2.2. Median and interquartile range

2.3. Minimum and maximum

3. Percentage of CC traced and quarantined

3.1. Number of traced CC (“verified CC”)

KPI3 is obtained from the division of 3.2 by 3.1a. Both 3.1 (including a/b), 3.2 and 3.3 are direct outputs from MCC. Results are stratified geo-temporally

70%

Outcome indicator rendering the quality of contact tracers’ duty. Two aspects are assessed:

1. contact notification, quarantine instructions recommendation, social support needs identification and COVID-19-like symptoms investigation over tracing call at day 0 (through KPI 3.1–2);

2. contact adherence to quarantine during follow-up calls at day 7 and 14 (through KPI 3.3).

3.1a. CC verified accepting follow-up

3.1b. CC verified to be excluded from follow-up

3.2. Number of verified CC accepting quarantine and follow-up

3.3. Total amount of follow-up calls performed (day 0, 7 and 14)

4. Percentage of new cases that were a known CC

4.1. Number of followed-up CC developing COVID-19 symptoms at tracing call

4.1 is a direct output from MCC, 4.2 being calculated from the division of 4.1 by 3.2. 4.3 is a direct output from T19 platform, 4.4 being calculated from the division of 4.3 by the number of confirmed cases in T19 within the period of study. Results are stratified geo-temporally

80% with sustained and gradual increase over time

Outcome indicator elucidating the control over transmission chains. The more suspected cases identified early, as well as new cases reporting having been exposed to a known case, the greater the traceability and prevention of transmission in the community. KPI4 is an indirect measure of the secondary attack rate in our setting at the moment of the study

4.2. Percentage of contacts with symptoms at tracing call

4.3. Number of new cases that were a known CC