Table 1. COVID-19 incidence, reported CICT program metrics, and CICT staff hours before and after CICT protocol change, Philadelphia, Pennsylvania, USA, 2021*.

Characteristic	Period 1, before protocol change	Period 2, after protocol change
Evaluation dates	Jun 23–Aug 17	Sep 1–Oct 26
COVID-19 incidence
Mean daily incidence, cases/100,000 persons†	9	18
Total no. reported cases	7,544	15,681
% Population fully vaccinated	58	65
CICT program performance metrics
No. case-patients reached for interviews‡	5,685	9,351
No. case-patients who completed interviews (% all case-patients)	3,172 (42)	4,537 (29)
No. interviewed case-patients naming >1 contact	852	1,074
No. contacts identified	1,922	2,375
No. contacts notified	1,372	1,853
No. contacts monitored§	883	1,234
Timing of case-patient interview, days after specimen collection¶	3	2
Timing of contact notification, days after specimen collection#	4	3
CICT staff hours
Average no. CICT staff per week	83	85
Total staff hours over the 8-wk period**	19,890	12,788

*CICT, case investigation and contact tracing. †Mean daily incidence for each of the 8-week evaluation periods. ‡Include case-patients who completed interviews, those who were reached but refused interview, and those who were reached but were unable to be interviewed because of other reasons (e.g., incarcerated, deceased, and language barriers). §Contacts who agreed to share symptom updates with the health department through text or phone calls. ¶Reported median days from specimen collection to positive test results reported to health departments. #Reported median days from specimen collection to contact notification. **On average, CICT staff spent 80% of their work (i.e., 30 h/wk) dedicated to CICT during period 1 and 50% during period 2 (i.e., 18.75 h/wk).